This patch enables software single stepping if the targets support it,
to do while-stepping actions.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (single_step): New function.
(linux_resume_one_lwp_throw): Call single_step.
(start_step_over): Likewise.
This patch in preparation for software single step support on ARM. It refactors
breakpoint_reinsert_addr into get_next_pcs so that multiple location can be
returned.
When software single stepping there can be multiple possible next addresses
because we're stepping over a conditional branch instruction, for example.
The operation get_next_pcs handles that by returning a vector of all the
possible next addresses.
Software breakpoints are installed at each location returned.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (the_low_targets): Rename
breakpoint_reinsert_addr to get_next_pcs.
* linux-arm-low.c (the_low_targets): Likewise.
* linux-bfin-low.c (the_low_targets): Likewise.
* linux-cris-low.c (the_low_targets): Likewise.
* linux-crisv32-low.c (the_low_targets): Likewise.
* linux-low.c (can_software_single_step): Likewise.
(install_software_single_step_breakpoints): New function.
(start_step_over): Use install_software_single_step_breakpoints.
* linux-low.h: New CORE_ADDR vector.
(struct linux_target_ops) Rename breakpoint_reinsert_addr to
get_next_pcs.
* linux-mips-low.c (the_low_targets): Likewise.
* linux-nios2-low.c (the_low_targets): Likewise.
* linux-sparc-low.c (the_low_targets): Likewise.
Since we now rely on PTRACE_EVENT_CLONE being available (added in
Linux 2.5.46), we're relying on NPTL.
This commit removes the support for older LinuxThreads, as well as the
workarounds for vendor 2.4 kernels with NPTL backported.
- Rely on tkill being available.
- Assume gdb doesn't get cancel signals.
- Remove code that checks the LinuxThreads restart and cancel signals
in the inferior.
- Assume that __WALL is available.
- Assume that non-leader threads report WIFEXITED.
- Thus, no longer need to send signal 0 to check whether threads are
still alive.
- Update comments throughout.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
* configure.ac: Remove tkill checks.
* configure, config.in: Regenerate.
* linux-nat.c: Remove HAVE_TKILL_SYSCALL check. Update top level
comments.
(linux_nat_post_attach_wait): Remove 'cloned' parameter. Use
__WALL.
(attach_proc_task_lwp_callback): Don't set the cloned flag.
(linux_nat_attach): Adjust.
(kill_lwp): Remove HAVE_TKILL_SYSCALL check. No longer fall back
to 'kill'.
(linux_handle_extended_wait): Use __WALL. Don't set the cloned
flag.
(wait_lwp): Use __WALL. Update comments.
(running_callback, stop_and_resume_callback): Delete.
(linux_nat_filter_event): Don't stop and resume all lwps. Don't
check if the event LWP has previously exited.
(check_zombie_leaders): Update comments.
(linux_nat_wait_1): Use __WALL.
(kill_wait_callback): Don't handle clone processes separately.
Use __WALL instead.
(linux_thread_alive): Delete.
(linux_nat_thread_alive): Return true as long as the LWP is in the
LWP list.
(linux_nat_update_thread_list): Assume the kernel supports
PTRACE_EVENT_CLONE.
(get_signo): Delete.
(lin_thread_get_thread_signals): Remove LinuxThreads references.
No longer check __pthread_sig_restart / __pthread_sig_cancel in
the inferior.
* linux-nat.h (struct lwp_info) <cloned>: Delete field.
* linux-thread-db.c: Update comments.
(_initialize_thread_db): Remove LinuxThreads references.
* nat/linux-waitpid.c (my_waitpid): No longer emulate __WALL.
Pass down flags unmodified.
* linux-waitpid.h (my_waitpid): Update documentation.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_kill_one_lwp): Remove references to
LinuxThreads.
(kill_lwp): Remove HAVE_TKILL_SYSCALL check. No longer fall back
to 'kill'.
(linux_init_signals): Delete.
(initialize_low): Adjust.
* thread-db.c (thread_db_init): Remove LinuxThreads reference.
Rename target_ops.arch_setup to .post_create_inferior. In the Linux
hook, continue calling the low arch setup, then also set ptrace flags.
This corrects the possibility of running without flags, demonstrated by
a new test that would fail to catch a fork before.
gdb/gdbserver/ChangeLog:
2015-12-04 Josh Stone <jistone@redhat.com>
* target.h (struct target_ops) <arch_setup>: Rename to ...
(struct target_ops) <post_create_inferior>: ... this.
(target_arch_setup): Rename to ...
(target_post_create_inferior): ... this, calling post_create_inferior.
* server.c (start_inferior): Update target_arch_setup calls to
target_post_create_inferior.
* linux-low.c (linux_low_ptrace_options): Forward declare.
(linux_arch_setup): Update its comment for general use.
(linux_post_create_inferior): New, run arch_setup and setup ptrace.
(struct linux_target_ops): Use linux_post_create_inferior.
* lynx-low.c (struct lynx_target_ops): Update arch_setup stub comment
to post_create_inferior.
* nto-low.c (struct nto_target_ops): Likewise.
* spu-low.c (struct spu_target_ops): Likewise.
* win32-low.c (struct win32_target_ops): Likewise.
gdb/testsuite/ChangeLog:
2015-12-04 Josh Stone <jistone@redhat.com>
* gdb.base/catch-fork-static.exp: New.
This patch removes support for thread events if PTRACE_EVENT_CLONE is not
supported in GDBServer.
Before, on systems that did not support PTRACE_EVENT_CLONE, both GDB and
GDBServer coordinated with libthread_db.so to insert breakpoints at magic
locations in libpthread.so, in order to break at thread creation and thread
death.
Simple software single stepping support was implemented to step over these
breakpoints in case there was no hardware single stepping support. However,
these simple software single stepping implementations were not fit for any other
use as discussed in :
https://sourceware.org/ml/gdb-patches/2015-04/msg01110.html
These too simple implementations conflict with ongoing work to make proper
implementations of software single stepping in GDBServer.
The problem is that if some implementations are correct and others are not and
only there for the thread magic breakpoint, we can't enable features based
solely software single step support since some would be broken.
To keep the incorrect implementations and allow the new proper ones at the same
time we would need to implement fallback code and it quickly becomes ugly and
confusing with multiple checks for legacy software single step or proper
software single step.
However, PTRACE_EVENT_CLONE was first introduced in Linux 2.5.46,
released in November 2002.
So I think it's reasonable to just remove support for kernels that don't support
PTRACE_EVENT_CLONE, and sidestep the libthread_db breakpoints issues entirely.
This thread on the mailling list discusses the issue :
https://sourceware.org/ml/gdb/2015-10/msg00078.html
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_look_up_symbols): Don't call
linux_supports_traceclone.
* linux-low.h (thread_db_init): Remove use_events argument.
* thread-db.c (thread_db_use_event): Remove global variable.
(struct thread_db) <td_thr_event_enable_p>: Remove field.
(struct thread_db) <td_create_bp>: Remove field.
(thread_db_create_event): Remove function.
(thread_db_enable_reporting): Likewise.
(find_one_thread): Don't check for thread_db_use_events.
(attach_thread): Likewise.
(thread_db_load_search): Remove td_thr_event_enable_p initialization.
(try_thread_db_load_1): Don't check for thread_db_use_events.
(thread_db_init): Remove use_events argument and thread events
handling.
(remove_thread_event_breakpoints): Remove function.
(thread_db_detach): Remove call to remove_thred_event_breakpoints.
Before this patch there was only one call: can_hardware_single_step. Its
implementation was a check on breakpoint_reinsert_addr if NULL it assumed
that the target could hardware single step.
This patch prepares for the case where this is not true anymore.
In order to improve software single stepping in GDBServer the
breakpoint_reinsert_addr operation of targets that had a very simple
software implementation used only for stepping over thread creation events
will be removed.
This will create a case where a target does not support hardware single
step and has the operation breakpoint_reinsert_addr set to NULL, thus
can_hardware_single_step needs to be implemented another way.
A new target operation supports_hardware_single_step is introduced and is
to return true if the target does support such a feature, support for the
feature is manually hardcoded.
Note that the hardware single step support was enabled as per the current
behavior, I did not check if tile for example really has ptrace singlestep
support but since the current implementation assumed it had, I kept it
that way.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
Compilation tested on: aarch64,arm,bfind,crisv32,m32r,ppc,s390,tic6x,tile,
xtensa.
Not tested : sh.
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-arm-low.c (arm_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-bfin-low.c (bfin_supports_hardware_single_step): New function.
(struct linux_target_ops) <bfin_supports_hardware_single_step>:
Initialize.
* linux-crisv32-low.c (cris_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-low.c (can_hardware_single_step): Use
supports_hardware_single_step.
(can_software_single_step): New function.
(start_step_over): Call can_software_single_step.
(linux_supports_hardware_single_step): New function.
(struct target_ops) <supports_software_single_step>: Initialize.
* linux-low.h (struct linux_target_ops)
<supports_hardware_single_step>: Initialize.
* linux-m32r-low.c (m32r_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-ppc-low.c (ppc_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step> Initialize.
* linux-s390-low.c (s390_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-sh-low.c (sh_supports_hardware_single_step): New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-tic6x-low.c (tic6x_supports_hardware_single_step): New function.
(struct linux_target_ops) <tic6x_supports_hardware_single_step>:
Initialize.
* linux-tile-low.c (tile_supports_hardware_single_step): New function.
(struct linux_target_ops) <tile_supports_hardware_single_step>:
Initialize.
* linux-x86-low.c (x86_supports_hardware_single_step) New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* linux-xtensa-low.c (xtensa_supports_hardware_single_step):
New function.
(struct linux_target_ops) <supports_hardware_single_step>: Initialize.
* target.h (struct target_ops): <supports_software_single_step>:
New field.
(target_supports_software_single_step): New macro.
Without this patch, when doing a software single step, with for example
a conditional breakpoint, gdbserver would wrongly avance the pc of
breakpoint_len and skips an instruction.
This is due to gdbserver assuming that it's hardware single stepping.
When it resumes from the breakpoint address it expects the trap to be
caused by ptrace and if it's rather caused by a software breakpoint
it assumes this is a permanent breakpoint and that it needs to skip
over it.
However when software single stepping, this breakpoint is legitimate as
it's the reinsert breakpoint gdbserver has put in place to break at
the next instruction. Thus gdbserver wrongly advances the pc and skips
an instruction.
This patch fixes this behavior so that gdbserver checks if it is a
reinsert breakpoint from software single stepping. If it is it won't
advance the pc. And if there's no reinsert breakpoint there we assume
then that it's a permanent breakpoint and advance the pc.
Here's a commented log of what would happen before and after the fix on
gdbserver :
/* Here there is a conditional breakpoint at 0x10428 that needs to be
stepped over. */
Need step over [LWP 11204]? yes, found breakpoint at 0x10428
...
/* e7f001f0 is a breakpoint instruction on arm
Here gdbserver writes the software breakpoint we would like to hit
*/
Writing e7f001f0 to 0x0001042c in process 11204
...
Resuming lwp 11220 (continue, signal 0, stop not expected)
pending reinsert at 0x10428
stop pc is 00010428
continue from pc 0x10428
...
/* Here gdbserver hit the software breakpoint that was in place
for the step over */
stop pc is 0001042c
pc is 0x1042c
step-over for LWP 11220.11220 executed software breakpoint
Finished step over.
Could not find fast tracepoint jump at 0x10428 in list (reinserting).
/* Here gdbserver writes back the original instruction */
Writing e50b3008 to 0x0001042c in process 11220
Step-over finished.
Need step over [LWP 11220]? No
/* Here because gdbserver assumes this is a permenant breakpoint it advances
the pc of breakpoint_len, in this case 4 bytes, so we have just skipped
the instruction that was written back here :
Writing e50b3008 to 0x0001042c in process 11220
*/
stop pc is 00010430
pc is 0x10430
Need step over [LWP 11220]? No, no breakpoint found at 0x10430
Proceeding, no step-over needed
proceed_one_lwp: lwp 11220
stop pc is 00010430
This patch fixes this situation and we get the right behavior :
Writing e50b3008 to 0x0001042c in process 11245
Hit a gdbserver breakpoint.
Hit a gdbserver breakpoint.
Step-over finished.
proceeding all threads.
Need step over [LWP 11245]? No
stop pc is 0001042c
pc is 0x1042c
Need step over [LWP 11245]? No, no breakpoint found at 0x1042c
Proceeding, no step-over needed
proceed_one_lwp: lwp 11245
stop pc is 0001042c
pc is 0x1042c
Resuming lwp 11245 (continue, signal 0, stop not expected)
stop pc is 0001042c
continue from pc 0x1042c
It also works if the value at 0x0001042c is a permanent breakpoint.
If so gdbserver will finish the step over, remove the reinserted breakpoint,
resume at that location and on the next SIGTRAP gdbserver will trigger
the advance PC condition as reinsert_breakpoint_inserted_here will be false.
I also tested this against bp-permanent.exp on arm (with a work in progress
software single step patchset) without any regressions.
It's also tested against x86 bp-permanent.exp without any regression.
So both software and hardware single step are tested.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_wait_1): Fix pc advance condition.
* mem-break.c (reinsert_breakpoint_inserted_here): New function.
* mem-break.h (reinsert_breakpoint_inserted_here): New declaration.
When manually stepping over a permanent breakpoint on ARM we need to fetch the
right breakpoint size based on the current instruction set used.
Since this is not encoded in the stop_pc, the instruction mode needs to be
fetched from the CPSR register.
This is done by introducing a new target operation called :
breakpoint_kind_from_current_state.
For other targets that do not need this, breakpoint_kind_from_pc is used.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-arm-low.c (arm_is_thumb_mode): New function.
(arm_breakpoint_at): Use arm_is_thumb_mode.
(arm_breakpoint_kind_from_current_state): New function.
(struct linux_target_ops) <breakpoint_kind_from_current_state>:
Initialize.
* linux-low.c (linux_wait_1): Call breakpoint_kind_from_current_state.
(linux_breakpoint_kind_from_current_state): New function.
(struct target_ops <breakpoint_kind_from_current_state>: Initialize.
* linux-low.h (struct linux_target_ops)
<breakpoint_kind_from_current_state>: New field.
* target.h (struct target_ops): Likewise.
(target_breakpoint_kind_from_current_state): New macro.
Running killed-outside.exp in with "maint set target-non-stop on"
hangs currently. This test has the inferior process die with a
SIGKILL while stopped. gdbserver gets a SIGCHLD and reacts by
retrieveing the SIGKILL events out of waitpid. But because the
process is not resumed from GDB's perspective, the event is left
pending. When GDB resumes the process afterwards, the process is not
really resumed because it already has the event pending. But nothing
wakes up the event loop to consume the event.
Handle this in the same way nat/linux-nat.c:linux_nat_resume handles
this.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_resume): Wake up the event loop before
returning.
Testing with "maint set target-non-stop on" causes regressions in
tests that rely on TARGET_WAITKIND_NO_RESUMED, which isn't modelled on
the RSP. In real all-stop, gdbserver detects the situation and
reporst error to GDB, and so the tests (e.g.,
gdb.threads/no-unwaited-for-left.exp) at fail quickly. But with
"maint set target-non-stop on", GDB instead hangs forever waiting for
a stop reply that never comes, and so the tests take longer to time
out.
This adds a new "N" stop reply packet that maps 1-1 to
TARGET_WAITKIND_NO_RESUMED.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* NEWS (New remote packets): Mention the N stop reply.
* remote.c (remote_protocol_features): Add "no-resumed" entry.
(remote_query_supported): Report no-resumed+ support.
(remote_parse_stop_reply): Handle 'N'.
(process_stop_reply): Handle TARGET_WAITKIND_NO_RESUMED.
(remote_wait_as): Handle 'N' / TARGET_WAITKIND_NO_RESUMED.
(_initialize_remote): Register "set/show remote
no-resumed-stop-reply" commands.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* gdb.texinfo (Stop Reply Packets): Document the N stop reply.
(Remote Configuration): Add the "set/show remote
no-resumed-stop-reply" to the available settings table.
(General Query Packets): Document the "no-resumed" qSupported
feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* linux-low.c (linux_wait_1): If the last resumed thread is gone,
report TARGET_WAITKIND_NO_RESUMED.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_NO_RESUMED.
* server.c (report_no_resumed): New global.
(handle_query) <qSupported>: Handle "no-resumed+". Report
"no-resumed+" support.
(resume): When the target reports TARGET_WAITKIND_NO_RESUMED, only
return error if the client doesn't support no-resumed events.
(push_stop_notification): New function.
(handle_target_event): Use it. Report TARGET_WAITKIND_NO_RESUMED
events if the client supports them.
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.threads/no-unwaited-for-left.exp: Remove setup_kfail calls.
killed-outside.exp regresses with "maint set target-non-stop on". The
logs show:
(gdb) continue
Continuing.
infrun: clear_proceed_status_thread (Thread 9028.9028)
infrun: proceed (addr=0xffffffffffffffff, signal=GDB_SIGNAL_DEFAULT)
infrun: proceed: resuming Thread 9028.9028
Sending packet: $Z0,3615a03966,1#4b... Notification received: Stop:X9;process:2344
Packet received: E01
Sending packet: $Z0,3615a13970,1#47...Packet received: E01
Sending packet: $Z0,3615a14891,1#4a...Packet received: E01
infrun: resume (step=0, signal=GDB_SIGNAL_0), trap_expected=0, current thread [Thread 9028.9028] at 0x4005e4
Sending packet: $vCont;c:p2344.2344#1a...Packet received: E.target not running.
Sending packet: $qXfer:threads:read::0,fff#03...Packet received: l<threads>\n</threads>\n
Sending packet: $vStopped#55...Packet received: OK
Unexpected vCont reply in non-stop mode: E.target not running.
(gdb) remote_async_inferior_event_handler
infrun: target_wait (-1.0.0, status) =
infrun: 9028.0.0 [process 9028],
infrun: status->kind = signalled, signal = GDB_SIGNAL_KILL
infrun: TARGET_WAITKIND_SIGNALLED
Program terminated with signal SIGKILL, Killed.
The program no longer exists.
infrun: stop_waiting
infrun: clear_step_over_info
infrun: stop_all_threads
remote_thread_exit_events(1)
Note the "Unexpected vCont reply" error.
I traced it to a problem in status_pending_p_callback. It resumes an
LWP when it shouldn't.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (thread_still_has_status_pending_p): Don't check
vCont;t here.
(lwp_resumed): New function.
(status_pending_p_callback): Return early if the LWP is not
supposed to be resumed.
When testing with "maint set target-non-stop on", a few
threading-related tests expose an issue that requires new RSP packets.
Say there are 3 threads running, 1-3. If GDB tries to stop thread 1,
2 and 3, and then waits for their stops, but meanwhile say, thread 2
exits, GDB hangs forever waiting for a stop for thread 2 that won't
ever happen.
This patch fixes the issue by adding support for thread exit events to
the protocol. However, we don't want these always enabled, as they're
useless most of the time, and would slow down remote debugging. So I
made it so that GDB can enable/disable them, and then made gdb do that
around the cases that need it, which currently is only
infrun.c:stop_all_threads.
In turn, if we have thread exit events, then the extra "thread x
exited" traffic slows down attach-many-short-lived-threads.exp enough
that gdb has trouble keeping up with new threads that are spawned
while gdb tries to stop existing ones. To fix that I added support
for the counterpart thread created events too. Enabling those when we
try to stop threads ensures that new threads never get a chance to
themselves start new threads, killing the race.
gdb/doc/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Remote Configuration): List "set/show remote
thread-events" command in configuration table.
(Stop Reply Packets): Document "T05 create" stop
reason and 'w' stop reply.
(General Query Packets): Document QThreadEvents packet. Document
QThreadEvents qSupported feature.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE. If GDB wants to hear about
thread create events, leave the new child's status pending.
(linux_low_filter_event): If GDB wants to hear about thread exit
events, leave the LWP marked dead and don't delete it.
(linux_wait_for_event_filtered): Don't check for thread exit.
(filter_exit_event): New function.
(linux_wait_1): Use it, when returning an exit event.
(linux_resume_one_lwp_throw): Assert that the LWP's
waitstatus is TARGET_WAITKIND_IGNORE.
* remote-utils.c (prepare_resume_reply): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* server.c (report_thread_events): New global.
(handle_general_set): Handle QThreadEvents.
(handle_query) <qSupported>: Handle and report QThreadEvents+;
(handle_target_event): Handle TARGET_WAITKIND_THREAD_CREATED and
TARGET_WAITKIND_THREAD_EXITED.
* server.h (report_thread_events): Declare.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* NEWS (New commands): Mention "set/show remote thread-events"
commands.
(New remote packets): Mention thread created/exited stop reasons
and QThreadEvents packet.
* infrun.c (disable_thread_events): New function.
(stop_all_threads): Disable/enable thread create/exit events.
Handle TARGET_WAITKIND_THREAD_EXITED.
(handle_inferior_event_1): Handle TARGET_WAITKIND_THREAD_CREATED
and TARGET_WAITKIND_THREAD_EXITED.
* remote.c (remove_child_of_pending_fork): Also remove threads of
threads that have TARGET_WAITKIND_THREAD_EXITED events.
(remote_parse_stop_reply): Handle "create" magic register. Handle
'w' stop reply.
(initialize_remote): Install remote_thread_events as
to_thread_events target hook.
(remote_thread_events): New function.
* target-delegates.c: Regenerate.
* target.c (target_thread_events): New function.
* target.h (struct target_ops) <to_thread_events>: New field.
(target_thread_events): Declare.
* target/waitstatus.c (target_waitstatus_to_string): Handle
TARGET_WAITKIND_THREAD_CREATED and TARGET_WAITKIND_THREAD_EXITED.
* target/waitstatus.h (enum target_waitkind)
<TARGET_WAITKIND_THREAD_CREATED, TARGET_WAITKIND_THREAD_EXITED):
New values.
Running attach-many-short-lived-threads.exp with the extended-remote
board with "maint set target-non-stop on" times out -- the attach
never completes. Enabling infrun debug logs, we see that GDB is stuck
stopping all threads:
infrun: target_wait (-1.0.0, status) =
infrun: 1639.22213.0 [Thread 1639.22213],
infrun: status->kind = stopped, signal = GDB_SIGNAL_0
infrun: Thread 1639.22260 not executing
infrun: Thread 1639.22256 not executing
infrun: Thread 1639.22258 not executing
infrun: Thread 1639.22257 not executing
infrun: Thread 1639.22259 not executing
infrun: Thread 1639.22255 not executing
infrun: Thread 1639.22253 executing, already stopping
infrun: Thread 1639.22251 executing, already stopping
infrun: Thread 1639.22252 executing, already stopping
infrun: Thread 1639.22250 executing, already stopping
infrun: Thread 1639.22254 executing, already stopping
infrun: Thread 1639.22247 executing, already stopping
infrun: Thread 1639.22213 not executing
infrun: Thread 1639.22207 not executing
infrun: Thread 1639.22201 not executing
infrun: Thread 1639.22219 not executing
infrun: Thread 1639.1639 not executing
** HANG HERE **
GDB is waiting for the stop replies of any of those "already stopping"
threads. Take 22253 for example. On the gdbserver logs we see:
...
resume_stop request for LWP 22253
stopping LWP 22253
Sending sigstop to lwp 22253
linux_resume done
...
and:
my_waitpid (-1, 0x40000001)
my_waitpid (-1, 0x80000001): status(3057f), 22253
LWFE: waitpid(-1, ...) returned 22253, ERRNO-OK
LLW: waitpid 22253 received Trace/breakpoint trap (stopped)
pc is 0x3615ef4ce1
HEW: Got clone event from LWP 22253, new child is LWP 22259
but from here on, we never see any other event for LWP 22253. In
particular, we never see the expected SIGSTOP (from "Sending sigstop"
above). The issue is that linux_resume_stopped_resumed_lwps never
re-resumes the 22253 after the clone event.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (resume_stopped_resumed_lwps): Don't check whether
the thread's last_resume_kind was resume_stop.
With "maint set target-non-stop on", the attach tests occasionally
crash gdbserver.
Basically, gdb attaches with vAttach;PID, and then shortly after reads
the xml target description for that process, to figure out the
process' architecture. On the gdbserver side, the target description
is only filled in when the first process/thread in the thread group
reports its initial PTRACE_ATTACH SIGSTOP. So if GDB is fast enough,
it can read the target description _before_ that initial stop, and
then gdbserver dies dereferencing a NULL tdesc pointer.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_attach): In non-stop mode, wait for one stop
before returning.
This patch adds support for thread names in the remote protocol, and
updates gdb/gdbserver to use it. The information is added to the XML
description sent in response to the qXfer:threads:read packet.
gdb/ChangeLog:
* linux-nat.c (linux_nat_thread_name): Replace implementation by call
to linux_proc_tid_get_name.
* nat/linux-procfs.c (linux_proc_tid_get_name): New function,
implementation inspired by linux_nat_thread_name.
* nat/linux-procfs.h (linux_proc_tid_get_name): New declaration.
* remote.c (struct private_thread_info) <name>: New field.
(free_private_thread_info): Free name field.
(remote_thread_name): New function.
(thread_item_t) <name>: New field.
(clear_threads_listing_context): Free name field.
(start_thread): Get name xml attribute.
(thread_attributes): Add "name" attribute.
(remote_update_thread_list): Copy name field.
(init_remote_ops): Assign remote_thread_name callback.
* target.h (target_thread_name): Update comment.
* NEWS: Mention remote thread name support.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_target_ops): Use linux_proc_tid_get_name.
* server.c (handle_qxfer_threads_worker): Refactor to include thread
name in reply.
* target.h (struct target_ops) <thread_name>: New field.
(target_thread_name): New macro.
gdb/doc/ChangeLog:
* gdb.texinfo (Thread List Format): Mention thread names.
The target_process_qsupported method is called for each qSupported
feature that the common code does not recognize. The only current
implementation, for x86 Linux (x86_linux_process_qsupported), assumes
that it either is called with the "xmlRegisters=i386" feature, or that
it is isn't called at all, indicating the connected GDB predates x86
XML descriptions.
That's a bad assumption however. If GDB sends in a new/unknown (to
core gdbserver) feature after "xmlRegisters=i386", say, something like
qSupported:xmlRegisters=i386;UnknownFeature+, then when
target_process_qsupported is called for "UnknownFeature+",
x86_linux_process_qsupported clears the 'use_xml' global and calls
x86_linux_update_xmltarget, and gdbserver ends up _not_ reporting a
XML description...
This commit changes the target_process_qsupported API to instead pass
down a vector of unprocessed qSupported features in one go.
(There's an early call to target_process_qsupported(NULL) that
indicates "starting qSupported processing". There's no matching call
to mark the end of processing, though. I first fixed this by passing
(char *)-1 to indicate that, and adjusted the x86 backend to only
clear 'use_xml' when qSupported processing starts, and then only call
x86_linux_update_xmltarget() when (char *)-1 was passed. However, I
wasn't that happy with the hack and came up this alternative version.)
gdb/gdbserver/ChangeLog:
2015-11-19 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_process_qsupported): Change prototype.
Adjust.
* linux-low.h (struct linux_target_ops) <process_qsupported>:
Change prototype.
* linux-x86-low.c (x86_linux_process_qsupported): Change prototype
and adjust to loop over all features.
* server.c (handle_query) <qSupported>: Adjust to call
target_process_qsupported once, passing it a vector of unprocessed
features.
* target.h (struct target_ops) <process_qsupported>: Change
prototype.
(target_process_qsupported): Adjust.
Fixes:
../../../src/gdb/gdbserver/linux-low.c: In function ‘int linux_low_read_btrace(btrace_target_info*, buffer*, int)’:
../../../src/gdb/gdbserver/linux-low.c:6827:48: error: invalid conversion from ‘int’ to ‘btrace_read_type’ [-fpermissive]
err = linux_read_btrace (&btrace, tinfo, type);
^
In file included from ../../../src/gdb/gdbserver/linux-low.c:98:0:
../../../src/gdb/gdbserver/../nat/linux-btrace.h:116:26: error: initializing argument 3 of ‘btrace_error linux_read_btrace(btrace_data*, btrace_target_info*, btrace_read_type)’ [-fpermissive]
extern enum btrace_error linux_read_btrace (struct btrace_data *btrace,
^
The cyclic dependency the comment talks about is no longer relevant:
https://sourceware.org/ml/gdb-patches/2015-10/msg00643.html
gdb/gdbserver/ChangeLog:
2015-10-29 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_low_read_btrace): Change type of 'type'
parameter.
* server.c (handle_qxfer_btrace): Change type of 'type'
local.
* target.h (struct target_ops) <read_btrace>: Change type of
'type' parameter. Update comment.
gdb/ChangeLog:
* nat/linux-nat.h (__SIGRTMIN): Move here from gdbserver/linux-low.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (__SIGRTMIN): Move to nat/linux-nat.h.
gdb/ChangeLog:
* common/gdb_wait.h (W_STOPCODE): Define, moved here from
gdbserver/linux-low.c.
(WSETSTOP): Simplify.
gdb/gdbserver/ChangeLog:
* linux-low.c (W_STOPCODE): Moved to common/gdb_wait.h.
This patch moves default_breakpoint_kind_from_pc to target.c and creates a macro
so that all targets can easily use it.
This allows the breakpoint_kind_from_pc operation to be left unimplemented in
targets that do not need it.
This is preparation to fix the win32/nto/spu build that was broken by this
patch: https://sourceware.org/ml/gdb-patches/2015-10/msg00369.html
No regression on Ubuntu 14.04 x86-64 with gdbserver-{native-extended}
gdb/gdbserver/ChangeLog:
* linux-low.c (default_breakpoint_kind_from_pc): Move to target.c.
* mem-break.c (set_breakpoint_at): Use target_breakpoint_kind_from_pc.
* target.c (default_breakpoint_kind_from_pc): Moved from linux-low.c
* target.h (target_breakpoint_kind_from_pc): New macro.
This patch fixes a regression introduced by :
https://sourceware.org/ml/gdb-patches/2015-10/msg00369.html
Tests : gdb.trace/trace-break.exp and gdb.trace/trace-mt.exp would fail on x86
with gdbserver-{native,extended}.
Before this patch, the breakpoint kind set by GDB with a Z packet and the one
set in the case of a tracepoint would be inconsistent on targets that did not
implement breakpoint_kind_from_pc. On x86 for example a breakpoint set by GDB
would have a kind of 1 but a breakpoint set by a tracepoint would have a kind of
0.
This created a missmatch when trying to insert a tracepoint and a breakpoint at
the same location. One of the two breakpoints would be removed with debug
message : "Inconsistent breakpoint kind".
This patch fixes the issue by changing the default 0 breakpoint kind to be
the size of the breakpoint according to sw_breakpoint_from_kind.
The default breakpoint kind must be the breakpoint length to keep consistency
between breakpoints set via GDB and the ones set internally by GDBServer.
No regression on Ubuntu 14.04 x86-64 with gdbserver-{native-extended}
gdb/gdbserver/ChangeLog:
* linux-low.c (default_breakpoint_kind_from_pc): New function.
(linux_breakpoint_kind_from_pc): Use default_breakpoint_kind_from_pc for
the default breakpoint kind.
There's two ways to set breakpoints in GDBServer.
- GDBServer setting its own breakpoints, through API set_breakpoint_at.
- GDBServer setting breakpoints according to the information in Z
packets, through API set_gdb_breakpoint.
Before this patch the breakpoint kinds were a concept unique to GDB and Z
packets, as GDBServer never had to set different kinds of breakpoint on its
own.
This patch teaches GDBServer to handle breakpoint kinds for its own
breakpoints. It generalizes the breakpoint kind as per Z packets to
represent different kinds of breakpoints directly set by GDBServer also.
GDBServer now querys breakpoint_kind_from_pc to know what breakpoint kind to
set on its own.
As the kind is now a differentiating factor equivalent to size for the
breakpoint struct and that it's size can be queried using
sw_breakpoint_from_kind, the size field has been replaced with the kind field.
All references to size are now replaced by kind or a call to bp_size that wraps
sw_breakpoing_from_kind and returns the size of the breakpoint in memory.
To fetch the software breakpoint data bp_opcode is called and wraps the
sw_breakpoint_from_kind call.
No regressions on Ubuntu 14.04 on ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
gdb/gdbserver/ChangeLog:
* linux-low.c (initialize_low): Ajdust for breakpoint global variables
removal.
* mem-break.c : Remove breakpoint_data/breakpoint_len global variables.
(struct raw_breakpoint) <size>: Remove.
(struct raw_breakpoint) <kind>: Add.
(bp_size): New function.
(bp_opcode): Likewise.
(find_raw_breakpoint_at): Adjust for kind.
(insert_memory_breakpoint): Adjust for kind call bp_size,bp_opcode.
(remove_memory_breakpoint): Adjust for kind call bp_size.
(set_raw_breakpoint_at): Adjust for kind.
(set_breakpoint): Likewise.
(set_breakpoint_at): Call breakpoint_kind_from_pc.
(delete_raw_breakpoint): Adjust for kind.
(delete_breakpoint): Likewise.
(find_gdb_breakpoint): Likewise.
(set_gdb_breakpoint_1): Likewise.
(set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint_1): Likewise.
(delete_gdb_breakpoint): Likewise.
(uninsert_raw_breakpoint): Likewise.
(reinsert_raw_breakpoint): Likewise.
(set_breakpoint_data): Remove.
(validate_inserted_breakpoint): Adjust for kind call bp_size,bp_opcode.
(check_mem_read): Adjust for kind call bp_size.
(check_mem_write): Adjust for kind call bp_size,bp_opcode.
(clone_one_breakpoint): Adjust for kind.
* mem-break.h (set_gdb_breakpoint): Likewise.
(delete_gdb_breakpoint): Likewise.
* server.c (process_serial_event): Likewise.
This patch is in preparation for software breakpoints on ARM linux. It
refactors breakpoint and breakpoint_len into breakpoint_kind_from_pc and
sw_breakpoint_from kind to prepare the case where we have multiple types of
breakpoints.
Kind is the type of breakpoint (hardware or software) to be inserted, usually it
is the lenght of the software breakpoint but can be something else depending on
the target.
This patch introduces the linux_target_ops breakpoint_kind_from_pc and
sw_breakpoint_from_kind.
breakpoint_kind_from_pc returns the breakpoint kind and adjusts the PC to the
real memory location in case a flag was present in the PC. E.g the instruction
mode on ARM.
sw_breakpoint_from_kind returns the software breakpoint for this kind as a
string of bytes, the length of the breakpoint is adjusted for the breakpoint's
size in memory.
For targets that have only one kind of breakpoint, the default value 0 is
returned by linux_breakpoint_kind_from_pc so that not all targets need to
implement the breakpoint_kind_from_pc operation.
No regressions, tested on Ubuntu 14.04 on ARMv7 and x86
With gdbserver-{native,extended} / { -marm -mthumb }
Also since the target_ops have been changed compilation was tested on
affected archs namely : aarch64, arm, bfin, cris, crisv32, m32r,
m68k, mips, nios2, ppc, s390, sparc, tic6x, tile, x86, steins.
Not tested : sh
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-arm-low.c (arm_breakpoint_kind_from_pc): New function.
(arm_sw_breakpoint_from_kind): New function.
* linux-bfin-low.c (bfin_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-cris-low.c (cris_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-crisv32-low.c (cris_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-low.c (linux_wait_1): Call breakpoint_kind_from_pc
and sw_breakpoint_from_kind to increment the pc.
(linux_breakpoint_kind_from_pc): New function.
(linux_sw_breakpoint_from_kind): New function.
(struct target_ops) <sw_breakpoint_from_kind>: Initialize field.
(initialize_low): Call breakpoint_kind_from_pc and
sw_breakpoint_from_kind to replace breakpoint_data/len.
* linux-low.h (struct linux_target_ops) <breakpoint_kind_from_pc>:
New field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Likewise.
* linux-m32r-low.c (m32r_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-m68k-low.c (m68k_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-mips-low.c (mips_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-nios2-low.c (nios2_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-ppc-low.c (ppc_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-s390-low.c (s390_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-sh-low.c (sh_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-sparc-low.c (sparc_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-tic6x-low.c (tic6x_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-tile-low.c (tile_sw_breakpoint_from_kind): New function.
* linux-x86-low.c (x86_sw_breakpoint_from_kind): New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
* linux-xtensa-low.c (xtensa_sw_breakpoint_from_kind) New function.
(struct linux_target_ops) <breakpoint>: Remove.
(struct linux_target_ops) <breakpoint_len>: Remove.
(struct linux_target_ops) <breakpoint_kind_from_pc>: Initialize field.
(struct linux_target_ops) <sw_breakpoint_from_kind>: Initialize field.
In my patch https://sourceware.org/ml/gdb-patches/2015-04/msg01110.html
a new target_ops hook supports_conditional_breakpoints was added to
disable conditional breakpoints if target doesn't have hardware single
step. This patch is to generalize this hook from
supports_conditional_breakpoints to supports_hardware_single_step,
so that the following patch can use it.
gdb/gdbserver:
2015-09-15 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_supports_conditional_breakpoints): Rename
it to ...
(linux_supports_hardware_single_step): ... New function.
(linux_target_ops): Update.
* lynx-low.c (lynx_target_ops): Set field
supports_hardware_single_step to target_can_do_hardware_single_step.
* nto-low.c (nto_target_ops): Likewise.
* spu-low.c (spu_target_ops): Likewise.
* win32-low.c (win32_target_ops): Likewise.
* target.c (target_can_do_hardware_single_step): New function.
* target.h (struct target_ops) <supports_conditional_breakpoints>:
Remove. <supports_hardware_single_step>: New field.
(target_supports_conditional_breakpoints): Remove.
(target_supports_hardware_single_step): New macro.
(target_can_do_hardware_single_step): Declare.
* server.c (handle_query): Use target_supports_hardware_single_step
instead of target_supports_conditional_breakpoints.
This patch implements support for exec events on extended-remote Linux
targets. Follow-exec-mode and rerun behave as expected. Catchpoints and
test updates are implemented in subsequent patches.
This patch was derived from a patch posted last October:
https://sourceware.org/ml/gdb-patches/2014-10/msg00877.html.
It was originally based on some work done by Luis Machado in 2013.
IMPLEMENTATION
----------------
Exec events are enabled via ptrace options.
When an exec event is detected by gdbserver, the existing process
data, along with all its associated lwp and thread data, is deleted
and replaced by data for a new single-threaded process. The new
process data is initialized with the appropriate parts of the state
of the execing process. This approach takes care of several potential
pitfalls, including:
* deleting the data for an execing non-leader thread before any
wait/sigsuspend occurs
* correctly initializing the architecture of the execed process
We then report the exec event using a new RSP stop reason, "exec".
When GDB receives an "exec" event, it saves the status in the event
structure's target_waitstatus field, like what is done for remote fork
events. Because the original and execed programs may have different
architectures, we skip parsing the section of the stop reply packet
that contains register data. The register data will be retrieved
later after the inferior's architecture has been set up by
infrun.c:follow_exec.
At that point the exec event is handled by the existing event handling
in GDB. However, a few changes were necessary so that
infrun.c:follow_exec could accommodate the remote target.
* Where follow-exec-mode "new" is handled, we now call
add_inferior_with_spaces instead of add_inferior with separate calls
to set up the program and address spaces. The motivation for this
is that add_inferior_with_spaces also sets up the initial architecture
for the inferior, which is needed later by target_find_description
when it calls target_gdbarch.
* We call a new target function, target_follow_exec. This function
allows us to store the execd_pathname in the inferior, instead of
using the static string remote_exec_file from remote.c. The static
string didn't work for follow-exec-mode "new", since once you switched
to the execed program, the original remote exec-file was lost. The
execd_pathname is now stored in the inferior's program space as a
REGISTRY field. All of the requisite mechanisms for this are
defined in remote.c.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_mourn): Static declaration.
(linux_arch_setup): Move in front of
handle_extended_wait.
(linux_arch_setup_thread): New function.
(handle_extended_wait): Handle exec events. Call
linux_arch_setup_thread. Make event_lwp argument a
pointer-to-a-pointer.
(check_zombie_leaders): Do not check stopped threads.
(linux_low_ptrace_options): Add PTRACE_O_TRACEEXEC.
(linux_low_filter_event): Add lwp and thread for exec'ing
non-leader thread if leader thread has been deleted.
Refactor code into linux_arch_setup_thread and call it.
Pass child lwp pointer by reference to handle_extended_wait.
(linux_wait_for_event_filtered): Update comment.
(linux_wait_1): Prevent clobbering exec event status.
(linux_supports_exec_events): New function.
(linux_target_ops) <supports_exec_events>: Initialize new member.
* lynx-low.c (lynx_target_ops) <supports_exec_events>: Initialize
new member.
* remote-utils.c (prepare_resume_reply): New stop reason 'exec'.
* server.c (report_exec_events): New global variable.
(handle_query): Handle qSupported query for exec-events feature.
(captured_main): Initialize report_exec_events.
* server.h (report_exec_events): Declare new global variable.
* target.h (struct target_ops) <supports_exec_events>: New
member.
(target_supports_exec_events): New macro.
* win32-low.c (win32_target_ops) <supports_exec_events>:
Initialize new member.
gdb/ChangeLog:
* infrun.c (follow_exec): Use process-style ptid for
exec message. Call add_inferior_with_spaces and
target_follow_exec.
* nat/linux-ptrace.c (linux_supports_traceexec): New function.
* nat/linux-ptrace.h (linux_supports_traceexec): Declare.
* remote.c (remote_pspace_data): New static variable.
(remote_pspace_data_cleanup): New function.
(get_remote_exec_file): New function.
(set_remote_exec_file_1): New function.
(set_remote_exec_file): New function.
(show_remote_exec_file): New function.
(remote_exec_file): Delete static variable.
(anonymous enum) <PACKET_exec_event_feature> New
enumeration constant.
(remote_protocol_features): Add entry for exec-events feature.
(remote_query_supported): Add client side of qSupported query
for exec-events feature.
(remote_follow_exec): New function.
(remote_parse_stop_reply): Handle 'exec' stop reason.
(extended_remote_run, extended_remote_create_inferior): Call
get_remote_exec_file and set_remote_exec_file_1.
(init_extended_remote_ops) <to_follow_exec>: Initialize new
member.
(_initialize_remote): Call
register_program_space_data_with_cleanup. Call
add_packet_config_cmd for remote exec-events feature.
Modify call to add_setshow_string_noescape_cmd for exec-file
to use new functions set_remote_exec_file and
show_remote_exec_file.
* target-debug.h, target-delegates.c: Regenerated.
* target.c (target_follow_exec): New function.
* target.h (struct target_ops) <to_follow_exec>: New member.
(target_follow_exec): Declare new function.
For the BTS recording format, we sometimes get a FROM->TO record where the
FROM address lies in the kernel and the TO address lies in user space at
whatever address the user process was resumed.
GDB has a heuristic to filter out such records based on looking at the most
significant bit in the PC. This works fine for 64-bit systems but it doesn't
always work for 32-bit systems. Libraries that are loaded at fairly high
addresses might be mistaken for kernel code and branches inside the library
are filtered out.
Change the heuristic to (again heuristically) try to determine the lowest
address in kernel space. Any PC that is smaller than that should be in
user space.
On today's systems, there should be a symbol "_text" at that address.
Read /proc/kallsyms and search for that symbol.
It is not guaranteed that /proc/kallsyms is readable on all systems. On
64-bit systems, we fall back to check the most significant bit. On 32-bit
systems, we refrain from filtering out addresses.
The filtering should really be done by the kernel. And it soon will be:
https://lkml.org/lkml/2015/8/31/212.
gdb/
* nat/linux-btrace.h (struct btrace_target_info) <ptr_bits>: Remove.
* nat/linux-btrace.c: Include filestuff.h and inttypes.h.
Remove include of sys/utsname.h.
(linux_determine_kernel_ptr_bits): Remove.
(linux_determine_kernel_start): New.
(perf_event_is_kernel_addr): Remove tinfo argument. Update users.
Update check.
(perf_event_skip_bts_record): Remove tinfo argument. Update users.
(linux_enable_bts, linux_enable_pt): Remove tinfo->ptr_bits
initialization.
* x86-linux-nat.c (x86_linux_enable_btrace): Remove ptr_bits
assignment.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Remove.
(linux_target_ops): Replace linux_low_enable_btrace with
linux_enable_btrace.
The Linux target and gdbserver now check the siginfo si_code
reported on a SIGTRAP to detect whether the trap indicates
a software breakpoint was hit.
Unfortunately, on Cell/B.E., the kernel uses an si_code value
of TRAP_BRKPT when a SW breakpoint was hit in PowerPC code,
but a si_code value of SI_KERNEL when a SW breakpoint was
hit in SPU code.
This patch updates Linux target and gdbserver to accept both
si_code values to indicate SW breakpoint on PowerPC.
ChangeLog:
* nat/linux-ptrace.h (GDB_ARCH_TRAP_BRKPT): Replace by ...
(GDB_ARCH_IS_TRAP_BRKPT): ... this. Add __powerpc__ case.
* linux-nat.c (check_stopped_by_breakpoint): Use
GDB_ARCH_IS_TRAP_BRKPT instead of GDB_ARCH_TRAP_BRKPT.
gdbserver/ChangeLog:
* linux-low.c (check_stopped_by_breakpoint): Use
GDB_ARCH_IS_TRAP_BRKPT instead of GDB_ARCH_TRAP_BRKPT.
In all-stop mode, if the current thread disappears while stopping all
threads, gdbserver calls set_desired_thread(0) ['0' means "I want the
continue thread"] which just picks the first thread in the list.
This looks like a dangerous thing to do. GDBserver continues
processing whatever it was doing, but to the wrong thread. If
debugging more than one process, we may even pick the wrong process.
Instead, GDBserver should detect the situation and bail out of
whatever is was doing.
The backends used to pay attention to the set 'cont_thread' (the Hc
thread, used in the old way to resume threads, before vCont), but all
such 'cont_thread' checks have been eliminated meanwhile. The
remaining implicit dependencies that I found on there being a selected
thread in the backends are in the Ctrl-C handling, which some backends
use as thread to send a signal to. Even that seems to me to be better
handled by always using the first thread in the list or by using the
signal_pid PID.
In order to make this a systematic approach, I'm making
set_desired_thread never fallback to a random thread, and instead end
up with current_thread == NULL, like already done in non-stop mode.
Then I updated all callers to handle the situation.
I stumbled on this while fixing other bugs exposed by
gdb.threads/fork-plus-threads.exp test. The problems I saw were fixed
in a different way, but in any case, I think the potential for
problems is more or less obvious, and the resulting code looks a bit
less magical to me.
Tested on x86-64 Fedora 20, w/ native-extended-gdbserver board.
gdb/gdbserver/ChangeLog:
2015-08-21 Pedro Alves <palves@redhat.com>
* linux-low.c (wait_for_sigstop): Always switch to no thread
selected if the previously current thread dies.
* lynx-low.c (lynx_request_interrupt): Use the first thread's
process instead of the current thread's.
* remote-utils.c (input_interrupt): Don't check if there's no
current thread.
* server.c (gdb_read_memory, gdb_write_memory): If setting the
current thread to the general thread fails, error out.
(handle_qxfer_auxv, handle_qxfer_libraries)
(handle_qxfer_libraries_svr4, handle_qxfer_siginfo)
(handle_qxfer_spu, handle_qxfer_statictrace, handle_qxfer_fdpic)
(handle_query): Check if there's a thread selected instead of
checking whether there's any thread in the thread list.
(handle_qxfer_threads, handle_qxfer_btrace)
(handle_qxfer_btrace_conf): Don't error out early if there's no
thread in the thread list.
(handle_v_cont, myresume): Don't set the current thread to the
continue thread.
(process_serial_event) <Hg handling>: Also set thread_id if the
previous general thread is still alive.
(process_serial_event) <g/G handling>: If setting the current
thread to the general thread fails, error out.
* spu-low.c (spu_resume, spu_request_interrupt): Use the first
thread's lwp instead of the current thread's.
* target.c (set_desired_thread): If the desired thread was not
found, leave the current thread pointing to NULL. Return an int
(boolean) indicating success.
* target.h (set_desired_thread): Change return type to int.
This tag allows debugging of MIPS position independent executables
and provides access to shared library information.
gdb/gdbserver/
* linux-low.c (get_r_debug): Handle DT_MIPS_RLD_MAP_REL.
gdb/
* solib-svr4.c (read_program_header): Add base_addr argument to
report the runtime address of the segment.
(find_program_interpreter): Update read_program_header call to pass
a NULL pointer for the new argument.
(scan_dyntag): Add ptr_addr argument to report the runtime address
of the tag payload.
(scan_dyntag_auxv): Likewise and use thew new base_addr argument of
read_program_header to get the base address of the dynamic segment.
(elf_locate_base): Update uses of scan_dyntag, scan_dyntag_auxv and
read_program_header.
(elf_locate_base): Scan for and handle DT_MIPS_RLD_MAP_REL.
While hacking on the fix for PR threads/18600 (Threads left stopped
after fork+thread spawn), I once saw its test (fork-plus-threads.exp)
FAIL against gdbserver because move_out_of_jump_pad_callback has a
gdb_breakpoint_here call, and the caller isn't making sure the current
thread points to the right thread. In the case I saw, the current
thread pointed to the wrong process, so gdb_breakpoint_here returned
the wrong answer. Unfortunately I didn't save logs. Still, seems
obvious enough and it should fix a potential occasional racy FAIL.
Tested on x86_64 Fedora 20.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (move_out_of_jump_pad_callback): Temporarily switch
the current thread.
Running gdbserver --debug under Valgrind shows:
==4803== Invalid read of size 4
==4803== at 0x432B62: linux_write_memory (linux-low.c:5320)
==4803== by 0x4143F7: write_inferior_memory (target.c:83)
==4803== by 0x415895: remove_memory_breakpoint (mem-break.c:362)
==4803== by 0x432EF5: linux_remove_point (linux-low.c:5460)
==4803== by 0x416319: delete_raw_breakpoint (mem-break.c:802)
==4803== by 0x4163F3: release_breakpoint (mem-break.c:842)
==4803== by 0x416477: delete_breakpoint_1 (mem-break.c:869)
==4803== by 0x4164EF: delete_breakpoint (mem-break.c:891)
==4803== by 0x416843: delete_gdb_breakpoint_1 (mem-break.c:1069)
==4803== by 0x4168D8: delete_gdb_breakpoint (mem-break.c:1098)
==4803== by 0x4134E3: process_serial_event (server.c:4051)
==4803== by 0x4138E4: handle_serial_event (server.c:4196)
==4803== Address 0x4c6b930 is 0 bytes inside a block of size 1 alloc'd
==4803== at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==4803== by 0x4240C6: xmalloc (common-utils.c:43)
==4803== by 0x41439C: write_inferior_memory (target.c:80)
==4803== by 0x415895: remove_memory_breakpoint (mem-break.c:362)
==4803== by 0x432EF5: linux_remove_point (linux-low.c:5460)
==4803== by 0x416319: delete_raw_breakpoint (mem-break.c:802)
==4803== by 0x4163F3: release_breakpoint (mem-break.c:842)
==4803== by 0x416477: delete_breakpoint_1 (mem-break.c:869)
==4803== by 0x4164EF: delete_breakpoint (mem-break.c:891)
==4803== by 0x416843: delete_gdb_breakpoint_1 (mem-break.c:1069)
==4803== by 0x4168D8: delete_gdb_breakpoint (mem-break.c:1098)
==4803== by 0x4134E3: process_serial_event (server.c:4051)
==4803==
And:
==7272== Conditional jump or move depends on uninitialised value(s)
==7272== at 0x3615E48361: vfprintf (vfprintf.c:1634)
==7272== by 0x414E89: debug_vprintf (debug.c:60)
==7272== by 0x42800A: debug_printf (common-debug.c:35)
==7272== by 0x43937B: my_waitpid (linux-waitpid.c:149)
==7272== by 0x42D740: linux_wait_for_event_filtered (linux-low.c:2441)
==7272== by 0x42DADA: linux_wait_for_event (linux-low.c:2552)
==7272== by 0x42E165: linux_wait_1 (linux-low.c:2860)
==7272== by 0x42F5D8: linux_wait (linux-low.c:3453)
==7272== by 0x4144A4: mywait (target.c:107)
==7272== by 0x413969: handle_target_event (server.c:4214)
==7272== by 0x41A1A6: handle_file_event (event-loop.c:429)
==7272== by 0x41996D: process_event (event-loop.c:184)
gdb/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* nat/linux-waitpid.c (my_waitpid): Only print *status if waitpid
returned > 0.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_write_memory): Rewrite debug output to avoid
reading beyond the passed in buffer length.
Ref: https://sourceware.org/ml/gdb-patches/2015-07/msg00868.html
This adds a test that has a multithreaded program have several threads
continuously fork, while another thread continuously steps over a
breakpoint.
This exposes several intertwined issues, which this patch addresses:
- When we're stopping and suspending threads, some thread may fork,
and we missed setting its suspend count to 1, like we do when a new
clone/thread is detected. When we next unsuspend threads, the fork
child's suspend count goes below 0, which is bogus and fails an
assertion.
- If a step-over is cancelled because a signal arrives, but then gdb
is not interested in the signal, we pass the signal straight back
to the inferior. However, we miss that we need to re-increment the
suspend counts of all other threads that had been paused for the
step-over. As a result, other threads indefinitely end up stuck
stopped.
- If a detach request comes in just while gdbserver is handling a
step-over (in the test at hand, this is GDB detaching the fork
child), gdbserver internal errors in stabilize_thread's helpers,
which assert that all thread's suspend counts are 0 (otherwise we
wouldn't be able to move threads out of the jump pads). The
suspend counts aren't 0 while a step-over is in progress, because
all threads but the one stepping past the breakpoint must remain
paused until the step-over finishes and the breakpoint can be
reinserted.
- Occasionally, we see "BAD - reinserting but not stepping." being
output (from within linux_resume_one_lwp_throw). That was because
GDB pokes memory while gdbserver is busy with a step-over, and that
suspends threads, and then re-resumes them with proceed_one_lwp,
which missed another reason to tell linux_resume_one_lwp that the
thread should be set back to stepping.
- In a couple places, we were resuming threads that are meant to be
suspended. E.g., when a vCont;c/s request for thread B comes in
just while gdbserver is stepping thread A past a breakpoint. The
resume for thread B must be deferred until the step-over finishes.
- The test runs with both "set detach-on-fork" on and off. When off,
it exercises the case of GDB detaching the fork child explicitly.
When on, it exercises the case of gdb resuming the child
explicitly. In the "off" case, gdb seems to exponentially become
slower as new inferiors are created. This is _very_ noticeable as
with only 100 inferiors gdb is crawling already, which makes the
test take quite a bit to run. For that reason, I've disabled the
"off" variant for now.
gdb/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* target/waitstatus.h (enum target_stop_reason)
<TARGET_STOPPED_BY_SINGLE_STEP>: New value.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Set the fork child's suspend
count if stopping and suspending threads.
(check_stopped_by_breakpoint): If stopped by trace, set the LWP's
stop reason to TARGET_STOPPED_BY_SINGLE_STEP.
(linux_detach): Complete an ongoing step-over.
(lwp_suspended_inc, lwp_suspended_decr): New functions. Use
throughout.
(resume_stopped_resumed_lwps): Don't resume a suspended thread.
(linux_wait_1): If passing a signal to the inferior after
finishing a step-over, unsuspend and re-resume all lwps. If we
see a single-step event but the thread should be continuing, don't
pass the trap to gdb.
(stuck_in_jump_pad_callback, move_out_of_jump_pad_callback): Use
internal_error instead of gdb_assert.
(enqueue_pending_signal): New function.
(check_ptrace_stopped_lwp_gone): Add debug output.
(start_step_over): Use internal_error instead of gdb_assert.
(complete_ongoing_step_over): New function.
(linux_resume_one_thread): Don't resume a suspended thread.
(proceed_one_lwp): If the LWP is stepping over a breakpoint, reset
it stepping.
gdb/testsuite/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* gdb.threads/forking-threads-plus-breakpoint.exp: New file.
* gdb.threads/forking-threads-plus-breakpoint.c: New file.
The tail end of linux_wait_1 isn't expecting that the select_event_lwp
machinery can pick a whole-process exit event to report to GDB. When
that happens, both gdb and gdbserver end up quite confused:
...
(gdb)
[Thread 24971.24971] #1 stopped.
0x0000003615a011f0 in ?? ()
c&
Continuing.
(gdb) [New Thread 24971.24981]
[New Thread 24983.24983]
[New Thread 24971.24982]
[Thread 24983.24983] #3 stopped.
0x0000003615ebc7cc in __libc_fork () at ../nptl/sysdeps/unix/sysv/linux/fork.c:130
130 pid = ARCH_FORK ();
[New Thread 24984.24984]
Error in re-setting breakpoint -16: PC register is not available
Error in re-setting breakpoint -17: PC register is not available
Error in re-setting breakpoint -18: PC register is not available
Error in re-setting breakpoint -19: PC register is not available
Error in re-setting breakpoint -24: PC register is not available
Error in re-setting breakpoint -25: PC register is not available
Error in re-setting breakpoint -26: PC register is not available
Error in re-setting breakpoint -27: PC register is not available
Error in re-setting breakpoint -28: PC register is not available
Error in re-setting breakpoint -29: PC register is not available
Error in re-setting breakpoint -30: PC register is not available
PC register is not available
(gdb)
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (add_lwp): Set waitstatus to TARGET_WAITKIND_IGNORE.
(linux_thread_alive): Use lwp_is_marked_dead.
(extended_event_reported): Delete.
(linux_wait_1): Check if waitstatus is TARGET_WAITKIND_IGNORE
instead of extended_event_reported.
(mark_lwp_dead): Don't set the 'dead' flag. Store the waitstatus
as well.
(lwp_is_marked_dead): New function.
(lwp_running): Use lwp_is_marked_dead.
* linux-low.h: Delete 'dead' field, and update 'waitstatus's
comment.
The "extended event with waitstatus" debug output is unreachable, as
it is guarded by "if (!report_to_gdb)". If extended_event_reported is
true, then so is report_to_gdb. Move it to where we print why we're
reporting an event to GDB.
Also, the debug output currently tries to print the wrong struct
target_waitstatus.
gdb/gdbserver/ChangeLog:
2015-08-06 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_wait_1): Move fork event output out of the
!report_to_gdb check. Pass event_child->waitstatus to
target_waitstatus_to_string instead of ourstatus.
This patch moves variable have_ptrace_getregset from linux-x86-low.c
to linux-low.c, so that arm can use it too.
gdb/gdbserver:
2015-08-04 Yao Qi <yao.qi@linaro.org>
* linux-x86-low.c (have_ptrace_getregset): Move it to ...
* linux-low.c: ... here.
* linux-low.h (have_ptrace_getregset): Declare it.
Running gdb.threads/fork-plus-threads.exp against gdbserver in
extended-remote mode, even though the test passes, we still see broken
behavior:
(gdb) PASS: gdb.threads/fork-plus-threads.exp: set detach-on-fork off
continue &
Continuing.
(gdb) PASS: gdb.threads/fork-plus-threads.exp: continue &
[New Thread 28092.28092]
[Thread 28092.28092] #2 stopped.
[New Thread 28094.28094]
[Inferior 2 (process 28092) exited normally]
[New Thread 28094.28105]
[New Thread 28094.28109]
...
[Thread 28174.28174] #18 stopped.
[New Thread 28185.28185]
[Inferior 10 (process 28174) exited normally]
[New Thread 28185.28196]
[Thread 28185.28185] #20 stopped.
Cannot remove breakpoints because program is no longer writable.
Further execution is probably impossible.
[Inferior 11 (process 28185) exited normally]
[Inferior 1 (process 28091) exited normally]
PASS: gdb.threads/fork-plus-threads.exp: reached breakpoint
info threads
No threads.
(gdb) PASS: gdb.threads/fork-plus-threads.exp: no threads left
info inferiors
Num Description Executable
* 1 <null> /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/fork-plus-threads
(gdb) PASS: gdb.threads/fork-plus-threads.exp: only inferior 1 left
All the "[Thread FOO] #NN stopped." above are bogus, as well as the
"Cannot remove breakpoints because program is no longer writable.",
which is a consequence.
The problem is that when we intercept a fork event, we should report
the event for the parent, only, and leave the child stopped, but not
report its stop event. GDB later decides whether to follow the parent
or the child. But because handle_extended_wait does not set the
child's last_status.kind to TARGET_WAITKIND_STOPPED, a
stop_all_threads/unstop_all_lwps sequence (e.g., from trying to access
memory) by mistake ends up queueing a SIGSTOP on the child, resuming
it, and then when that SIGSTOP is intercepted, because the LWP has
last_resume_kind set to resume_stop, gdbserver reports the stop to
GDB, as GDB_SIGNAL_0:
...
>>>> entering unstop_all_lwps
unstopping all lwps
proceed_one_lwp: lwp 1600
client wants LWP to remain 1600 stopped
proceed_one_lwp: lwp 1828
Client wants LWP 1828 to stop. Making sure it has a SIGSTOP pending
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Sending sigstop to lwp 1828
pc is 0x3615ebc7cc
Resuming lwp 1828 (continue, signal 0, stop expected)
continue from pc 0x3615ebc7cc
unstop_all_lwps done
sigchld_handler
<<<< exiting unstop_all_lwps
handling possible target event
>>>> entering linux_wait_1
linux_wait_1: [<all threads>]
my_waitpid (-1, 0x40000001)
my_waitpid (-1, 0x1): status(137f), 1828
LWFE: waitpid(-1, ...) returned 1828, ERRNO-OK
LLW: waitpid 1828 received Stopped (signal) (stopped)
pc is 0x3615ebc7cc
Expected stop.
LLW: resume_stop SIGSTOP caught for LWP 1828.1828.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
...
linux_wait_1 ret = LWP 1828.1828, 1, 0
<<<< exiting linux_wait_1
Writing resume reply for LWP 1828.1828:1
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Tested on x86_64 Fedora 20, extended-remote.
gdb/gdbserver/ChangeLog:
2015-07-30 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Set the child's last
reported status to TARGET_WAITKIND_STOPPED.
As the result of the previous patch, new_inferior is no longer used.
This patch is to remove it.
gdb/gdbserver:
2015-07-24 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_create_inferior): Remove setting to
proc->priv->new_inferior.
(linux_attach): Likewise.
(linux_low_filter_event): Likewise.
* linux-low.h (struct process_info_private) <new_inferior>: Remove.
Nowadays, when --wrapper is used, GDBserver skips extra traps/stops
in the wrapper program, and stops at the first instruction of the
program to be debugged. However, GDBserver created target description
in the first stop of inferior, and the executable of the inferior
is the wrapper program rather than the program to be debugged. In
this way, the target description can be wrong if the architectures
of wrapper program and program to be debugged are different. This
is shown by some fails in gdb.server/wrapper.exp on buildbot.
We are testing i686-linux GDB (Fedora-i686) on an x86_64-linux box
(fedora-x86-64-4) in buildbot, such configuration causes fails in
gdb.server/wrapper.exp like this:
spawn /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/../../gdb/gdbserver/gdbserver --once --wrapper env TEST=1 -- :2346 /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/outputs/gdb.server/wrapper/wrapper
Process /home/gdb-buildbot-2/fedora-x86-64-4/fedora-i686/build/gdb/testsuite/outputs/gdb.server/wrapper/wrapper created; pid = 8795
Can't debug 64-bit process with 32-bit GDBserver
Exiting
target remote localhost:2346
localhost:2346: Connection timed out.
(gdb) FAIL: gdb.server/wrapper.exp: setting breakpoint at marker
See https://sourceware.org/ml/gdb-testers/2015-q3/msg01541.html
In this case, program to be debugged ("wrapper") is 32-bit but wrapper
program ("/usr/bin/env") is 64-bit, so GDBserver gets the 64-bit
target description instead of 32-bit.
The root cause of this problem is that GDBserver creates target
description too early, and the rationale of fix could be creating
target description once the GDBserver skips extra traps and inferior
stops at the first instruction of the program we want to debug. IOW,
when GDBserver skips extra traps, the inferior's tdesc is NULL, and
mywait and its callees shouldn't use inferior's tdesc, so in this
patch, we skip code that requires register access, see changes in
linux_resume_one_lwp_throw and need_step_over_p.
In linux_low_filter_event, if target description isn't initialised and
GDBserver attached the process, we create target description immediately,
because GDBserver don't have to skip extra traps for attach, IOW, it
makes no sense to use --attach and --wrapper together. Otherwise, the
process is launched by GDBserver, we keep the status pending, and return.
After GDBserver skipped extra traps in start_inferior, we call a
target_ops hook arch_setup to initialise target description there.
gdb/gdbserver:
2015-07-24 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_arch_setup): New function.
(linux_low_filter_event): If proc->tdesc is NULL and
proc->attached is true, call the_low_target.arch_setup.
Otherwise, keep status pending, and return.
(linux_resume_one_lwp_throw): Don't call get_pc if
thread->while_stepping isn't NULL. Don't call
get_thread_regcache if proc->tdesc is NULL.
(need_step_over_p): Return 0 if proc->tdesc is NULL.
(linux_target_ops): Install arch_setup.
* server.c (start_inferior): Call the_target->arch_setup.
* target.h (struct target_ops) <arch_setup>: New field.
(target_arch_setup): New marco.
* lynx-low.c (lynx_target_ops): Update.
* nto-low.c (nto_target_ops): Update.
* spu-low.c (spu_target_ops): Update.
* win32-low.c (win32_target_ops): Update.
Nowadays, we set proc->priv->new_inferior to 1 inside linux_add_process,
and new_inferior is used as a flag to initialise target description later.
linux_add_process is used for the three cases, fork/vfork event
(handle_extended_wait), run the program (linux_create_inferior), and
attach to the process (linux_attach). In the first case, the child's
target description is copied from parent's, so we don't need to initialise
target description again later, which means we don't need to set
proc->priv->new_inferior to 1 in this case. For the rest of two cases,
we need this flag.
This patch move the code setting proc->priv->new_inferior to 1 inside
linux_add_process to linux_create_inferior and linux_attach. No
functionality is changed.
gdb/gdbserver:
2015-07-24 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_add_process): Don't set
proc->priv->new_inferior.
(linux_create_inferior): Set proc->priv->new_inferior to 1.
(linux_attach): Likewise.
Producer part of the new "build-id" XML attribute.
gdb/ChangeLog
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* features/library-list-svr4.dtd (library-list-svr4): New
'build-id' attribute.
gdb/doc/ChangeLog
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* gdb.texinfo (Library List Format for SVR4 Targets): Add
'build-id' in description, example, new attribute in dtd.
gdb/gdbserver/ChangeLog
2015-07-15 Aleksandar Ristovski <aristovski@qnx.com
Jan Kratochvil <jan.kratochvil@redhat.com>
gdbserver build-id attribute generator.
* linux-low.c (nat/linux-maps.h, search.h, rsp-low.h): Include.
(ElfXX_Ehdr, ElfXX_Phdr, ElfXX_Nhdr): New.
(ELFXX_FLD, ELFXX_SIZEOF, ELFXX_ROUNDUP, BUILD_ID_INVALID): New.
(find_phdr): New.
(get_dynamic): Use find_pdhr to traverse program headers.
(struct mapping_entry, mapping_entry_s, free_mapping_entry_vec)
(compare_mapping_entry_range, struct find_memory_region_callback_data)
(read_build_id, find_memory_region_callback, lrfind_mapping_entry)
(get_hex_build_id): New.
(linux_qxfer_libraries_svr4): Add optional build-id attribute
to reply XML document.
If the process disappears (e.g., killed with "kill -9" from the shell)
while it was stopped under GDBserver's control, and the GDBserver
tries to kill it, GDBserver asserts:
(gdb) shell kill -9 23084
(gdb) kill
...
Killing process(es): 23084
/home/pedro/gdb/mygit/src/gdb/gdbserver/linux-low.c:972: A problem internal to GDBserver has been detected.
kill_wait_lwp: Assertion `res > 0' failed.
...
gdb/gdbserver/ChangeLog:
2015-07-14 Pedro Alves <palves@redhat.com>
* linux-low.c (kill_wait_lwp): Don't assert if waitpid fails.
Instead, ignore ECHILD, and throw an error for other errnos.
Adds a new command "record btrace pt" to configure the kernel to use
Intel(R) Processor Trace instead of Branch Trace Strore.
The "record btrace" command chooses the tracing format automatically.
Intel(R) Processor Trace support requires Linux 4.1 and libipt.
gdb/
* NEWS: Announce new commands "record btrace pt" and "record pt".
Announce new options "set|show record btrace pt buffer-size".
* btrace.c: Include "rsp-low.h".
Include "inttypes.h".
(btrace_add_pc): Add forward declaration.
(pt_reclassify_insn, ftrace_add_pt, btrace_pt_readmem_callback)
(pt_translate_cpu_vendor, btrace_finalize_ftrace_pt)
(btrace_compute_ftrace_pt): New.
(btrace_compute_ftrace): Support BTRACE_FORMAT_PT.
(check_xml_btrace_version): Update version check.
(parse_xml_raw, parse_xml_btrace_pt_config_cpu)
(parse_xml_btrace_pt_raw, parse_xml_btrace_pt)
(btrace_pt_config_cpu_attributes, btrace_pt_config_children)
(btrace_pt_children): New.
(btrace_children): Add support for "pt".
(parse_xml_btrace_conf_pt, btrace_conf_pt_attributes): New.
(btrace_conf_children): Add support for "pt".
* btrace.h: Include "intel-pt.h".
(btrace_pt_error): New.
* common/btrace-common.c (btrace_format_string, btrace_data_fini)
(btrace_data_empty): Support BTRACE_FORMAT_PT.
* common/btrace-common.h (btrace_format): Add BTRACE_FORMAT_PT.
(struct btrace_config_pt): New.
(struct btrace_config)<pt>: New.
(struct btrace_data_pt_config, struct btrace_data_pt): New.
(struct btrace_data)<pt>: New.
* features/btrace-conf.dtd (btrace-conf)<pt>: New.
(pt): New.
* features/btrace.dtd (btrace)<pt>: New.
(pt, pt-config, cpu): New.
* nat/linux-btrace.c (perf_event_read, perf_event_read_all)
(perf_event_pt_event_type, kernel_supports_pt)
(linux_supports_pt): New.
(linux_supports_btrace): Support BTRACE_FORMAT_PT.
(linux_enable_bts): Free tinfo on error.
(linux_enable_pt): New.
(linux_enable_btrace): Support BTRACE_FORMAT_PT.
(linux_disable_pt): New.
(linux_disable_btrace): Support BTRACE_FORMAT_PT.
(linux_fill_btrace_pt_config, linux_read_pt): New.
(linux_read_btrace): Support BTRACE_FORMAT_PT.
* nat/linux-btrace.h (struct btrace_tinfo_pt): New.
(struct btrace_target_info)<pt>: New.
* record-btrace.c (set_record_btrace_pt_cmdlist)
(show_record_btrace_pt_cmdlist): New.
(record_btrace_print_pt_conf): New.
(record_btrace_print_conf): Support BTRACE_FORMAT_PT.
(btrace_ui_out_decode_error): Support BTRACE_FORMAT_PT.
(cmd_record_btrace_pt_start): New.
(cmd_record_btrace_start): Support BTRACE_FORMAT_PT.
(cmd_set_record_btrace_pt, cmd_show_record_btrace_pt): New.
(_initialize_record_btrace): Add new commands.
* remote.c (PACKET_Qbtrace_pt, PACKET_Qbtrace_conf_pt_size): New.
(remote_protocol_features): Add "Qbtrace:pt".
Add "Qbtrace-conf:pt:size".
(remote_supports_btrace): Support BTRACE_FORMAT_PT.
(btrace_sync_conf): Support PACKET_Qbtrace_conf_pt_size.
(remote_enable_btrace): Support BTRACE_FORMAT_PT.
(_initialize_remote): Add new commands.
gdbserver/
* linux-low.c: Include "rsp-low.h"
(linux_low_encode_pt_config, linux_low_encode_raw): New.
(linux_low_read_btrace): Support BTRACE_FORMAT_PT.
(linux_low_btrace_conf): Support BTRACE_FORMAT_PT.
(handle_btrace_enable_pt): New.
(handle_btrace_general_set): Support "pt".
(handle_btrace_conf_general_set): Support "pt:size".
doc/
* gdb.texinfo (Process Record and Replay): Spell out that variables
and registers are not available during btrace replay.
Describe the new "record btrace pt" command.
Describe the new "set|show record btrace pt buffer-size" options.
(General Query Packets): Describe the new Qbtrace:pt and
Qbtrace-conf:pt:size packets.
Expand "bts" to "Branch Trace Store".
Update the branch trace DTD.
This commit implements the "vFile:setfs" packet in gdbserver.
gdb/gdbserver/ChangeLog:
* target.h (struct target_ops) <multifs_open>: New field.
<multifs_unlink>: Likewise.
<multifs_readlink>: Likewise.
* linux-low.c (nat/linux-namespaces.h): New include.
(linux_target_ops): Initialize the_target->multifs_open,
the_target->multifs_unlink and the_target->multifs_readlink.
* hostio.h (hostio_handle_new_gdb_connection): New declaration.
* hostio.c (hostio_fs_pid): New static variable.
(hostio_handle_new_gdb_connection): New function.
(handle_setfs): Likewise.
(handle_open): Use the_target->multifs_open as appropriate.
(handle_unlink): Use the_target->multifs_unlink as appropriate.
(handle_readlink): Use the_target->multifs_readlink as
appropriate.
(handle_vFile): Handle vFile:setfs packets.
* server.c (handle_query): Call hostio_handle_new_gdb_connection
after target_handle_new_gdb_connection.
This patch fixes some intermittent test failures in
gdb.base/foll-vfork.exp where a vfork child would be (incorrectly)
resumed when handling the vfork event. In this case the result
was a subsequent event reported to the client side as a SIGTRAP
delivered to the as-yet-unknown child thread.
The new thread was resumed (incorrectly) in linux-low.c when
resume_stopped_resumed_lwps was called from
linux_wait_for_event_filtered after the vfork event had been
handled in handle_extended_wait.
Gdbserver/linux-low.c's add_thread function creates threads with
last_resume_kind == resume_continue by default. This field is
used by resume_stopped_resumed_lwps to decide whether to perform
the resume:
static void
resume_stopped_resumed_lwps (struct inferior_list_entry *entry) {
struct thread_info *thread = (struct thread_info *) entry;
struct lwp_info *lp = get_thread_lwp (thread);
if (lp->stopped
&& !lp->status_pending_p
&& thread->last_resume_kind != resume_stop
&& thread->last_status.kind == TARGET_WAITKIND_IGNORE)
{
So the fix is to make sure to set thread->last_resume_kind to
resume_stop. Here we do that for new fork children in
gdbserver/linux-low.c:handle_extended_wait.
In addition, it seemed prudent to initialize lwp_info.status_pending_p
for the new fork child. I also rearranged the initialization code
so that all of the lwp_info initialization was together, rather than
intermixed with thread_info and process_info initialization.
Tested native, native-gdbserver, native-extended-gdbserver on
x86_64 GNU/Linux.
gdb/gdbserver/
* linux-low.c (handle_extended_wait): Initialize
thread_info.last_resume_kind for new fork children.
This patch implements follow-fork for vfork on extended-remote Linux targets.
The implementation follows the native implementation as much as possible.
Most of the work is done on the GDB side in the existing code now in
infrun.c. GDBserver just has to report the events and do a little
bookkeeping.
Implementation includes:
* enabling VFORK events by adding ptrace options for VFORK and VFORK_DONE
to linux-low.c:linux_low_ptrace_options.
* handling VFORK and VFORK_DONE events in linux-low.c:handle_extended_wait
and reporting them to GDB.
* including VFORK and VFORK_DONE events in the predicate
linux-low.c:extended_event_reported.
* adding support for VFORK and VFORK_DONE events in RSP by adding stop
reasons "vfork" and "vforkdone" to the 'T' Stop Reply Packet in both
gdbserver/remote-utils.c and gdb/remote.c.
Tested on x64 Ubuntu Lucid, native, remote, extended-remote.
gdb/gdbserver/ChangeLog:
* linux-low.c (handle_extended_wait): Handle PTRACE_EVENT_FORK and
PTRACE_EVENT_VFORK_DONE.
(linux_low_ptrace_options, extended_event_reported): Add vfork
events.
* remote-utils.c (prepare_resume_reply): New stop reasons "vfork"
and "vforkdone" for RSP 'T' Stop Reply Packet.
* server.h (report_vfork_events): Declare
global variable.
gdb/ChangeLog:
* remote.c (remove_vfork_event_p): New function.
(remote_follow_fork): Add vfork event type to event checking.
(remote_parse_stop_reply): New stop reasons "vfork" and
"vforkdone" for RSP 'T' Stop Reply Packet.
Antoine Tremblay
Pedro Alves
Josh Stone
Simon Marchi
Doug Evans
Yao Qi
Don Breazeal
Markus Metzger
Ulrich Weigand
Matthew Fortune
Jan Kratochvil
Gary Benson