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.
Linker can't optimize R_386_GOT32 and R_386_GOT32X relocations if addend
isn't 0. It isn't valid to convert
movl foo@GOT+1(%ecx), %eax
to
leal foo@GOTOFF+1(%ecx), %eax
nor to convert
movq foo@GOTPCREL+1(%rip), %rax
to
leaq foo(%rip), %rax
for x86-64. We should check if addend is 0 before optimizing R_386_GOT32
and R_386_GOT32X relocations. Testcases are added for i386 and x86-64.
bfd/
* elf32-i386.c (elf_i386_convert_load): Skip if addend isn't 0.
(elf_i386_relocate_section): Skip R_386_GOT32X optimization if
addend isn't 0.
ld/testsuite/
* ld-i386/i386.exp: Run mov2a, mov2b and mov3.
* ld-i386/mov2.s: New file.
* ld-i386/mov2a.d: Likewise.
* ld-i386/mov2b.d: Likewise.
* ld-i386/mov3.d: Likewise.
* ld-i386/mov3.s: Likewise.
* ld-x86-64/mov2.s: Likewise.
* ld-x86-64/mov2a.d: Likewise.
* ld-x86-64/mov2b.d: Likewise.
* ld-x86-64/mov2c.d: Likewise.
* ld-x86-64/mov2d.d: Likewise.
* ld-x86-64/x86-64.exp: Run mov2a, mov2b, mov2c and mov2d.
PR gas/19276
gas * config/tc-arm.h (SUB_SEGMENT_ALIGN): Do not define for COFF/PE
targets.
testsuite * gas/arm/align64.d: Skip for COFF/PE targets.
* gas/arm/bundle-lock.d: Adjust for COFF/PE targets.
gold/
* object.cc (Sized_relobj::do_for_all_local_got_entries): Use
Local_got_entry_key for searching in local_got_offsets_.
* object.h (class Local_got_entry_key): New class.
(Relobj::local_has_got_offset): New overloaded method.
(Relobj::local_got_offset): Likewise.
(Relobj::set_local_got_offset): Likewise.
(Relobj::do_local_has_got_offset): Add addend argument.
(Relobj::do_local_got_offset): Likewise.
(Relobj::do_set_local_got_offset): Likewise.
(Sized_relobj::do_local_has_got_offset): Add addend argument, and use
Local_got_entry_key for searching through local_got_offsets_.
(Sized_relobj::do_local_got_offset): Likewise.
(Sized_relobj::do_set_local_got_offset): Likewise.
(Sized_relobj::Local_got_offsets): Change type of the key from
unsigned int to Local_got_entry_key, and add hash and equal_to.
* output.cc (Got_entry::write): Take addend into account for
calculating value of the local symbol for GOT.
(Output_data_got::add_local): New definition of overloaded method.
(Output_data_got::add_local_with_rel): Likewise.
(Output_data_got::add_local_pair_with_rel): Likewise.
* output.h (Output_data_got::add_local): New declaration of overloaded
method.
A duplicate include arm/arm.h was introduced, remove it.
Pushed as obvious.
gdb/gdbserver/ChangeLog:
* linux-arm-low.c: Remove duplicate arch/arm.h include.
In my remote cross testing (x86_64 host and aarch64 target), the test
gdb.base/sizeof.exp is skipped because gdb,noinferiorio is defined in
my gdbserver board file. Tests are skipped because the test checks
the expected value from the program's output, but I don't see why must
do it this way. With my patch applied, we can save the result in variable
in the program, and check the variable then. Then, the test doesn't rely
on inferiorio.
gdb/testsuite:
2015-12-03 Yao Qi <yao.qi@linaro.org>
* gdb.base/sizeof.c: Don't include stdio.h and
../lib/unbuffer_output.c.
(main): New variable 'size' and 'value'. Remove printf and
gdb_unbuffer_output. Assign return value to size and value.
* gdb.base/sizeof.exp: Remove the checking to gdb,noinferiorio
at the beginning.
(check_sizeof): Check the result by printing variable 'size'.
(check_valueof): Check the result by printing variable 'value'.
In this case the inlined function doesn't have DW_AT_linkage_name in
.debug_info, but the language is C++ so find_nearest_line goes looking
in the symbol table. Since the function is inlined the enclosing
non-inline function symbol is returned from _bfd_elf_find_function,
which is wrong. This patch only uses a symbol if its address matches.
PR binutils/19315
* dwarf2.c (_bfd_elf_find_function): Return symbol matched.
(_bfd_dwarf2_find_nearest_line): Check symbol returned above
against dwarf range.
* elf-bfd.h (_bfd_elf_find_function): Update prototype.
Fixes a segfault in ppc64_elf_tls_optimize found when testing
R_PPC64_ENTRY, and potential for trouble in other places found by
code inspection.
* elf64-ppc.c (ppc64_elf_tls_optimize): Don't segfault on NULL
symbol section or output section.
(ppc64_elf_edit_toc): Similarly for ld -R objects.
(ppc64_elf_size_stubs): Likewise.
Symbol defined by a linker assignment may have type bfd_link_hash_new
or bfd_link_hash_undefined. And h->def_regular is always set.
elf_i386_convert_load and elf_x86_64_convert_load should check
h->def_regular as well as bfd_link_hash_undefined and bfd_link_hash_new
to see if a symbol is defined by a linker script.
bfd/
PR ld/19319
* elf32-i386.c (elf_i386_convert_load): Check h->def_regular
instead of bfd_link_hash_new.
* elf64-x86-64.c (elf_x86_64_convert_load): Likewise. Skip
relocation overflow for bfd_link_hash_undefined and
bfd_link_hash_new if h->def_regular is set.
ld/testsuite/
PR ld/19319
* ld-i386/i386.exp: Run pr19319 test.
* ld-x86-64/x86-64.exp: Likewise.
* ld-i386/pr19319.dd: New file.
* ld-i386/pr19319a.S: Likewise.
* ld-i386/pr19319b.S: Likewise.
* ld-x86-64/pr19319.dd: Likewise.
* ld-x86-64/pr19319a.S: Likewise.
* ld-x86-64/pr19319b.S: Likewise.
GCC 4.1 gives the following warning:
gdb/remote.c: In function 'remote_parse_stop_reply':
gdb/remote.c:6549: warning: operation on 'p' may be undefined
on this line of code:
event->ptid = read_ptid (++p, &p);
Since p actually isn't used afterwards anyway, simply use NULL.
gdb/
* remote.c (remote_parse_stop_reply): Avoid GCC 4.1 "operation
may be undefined" warning.
Fix a couple of places where a struct thread_item was added to a
vector while the item.name field was uninitialized.
gdb/
* remote.c (remote_newthread_step): Initialize item.name.
(remote_get_threads_with_qthreadinfo): Likewise.
info->traditional_format is available, or can be easily made
available. This relegates BFD_TRADITIONAL_FORMAT to AOUT use only.
* coff-rs6000.c (_bfd_xcoff_put_symbol_name): Replace abfd param
with info param. Test info->traditional_format rather than
BFD_TRADITIONAL_FORMAT flag.
* coff64-rs6000.c (_bfd_xcoff64_put_symbol_name): Likewise.
* libxcoff.h (struct xcoff_backend_data_rec): Update
_xcoff_put_symbol_name prototype.
(bfd_xcoff_put_symbol_name): Add info param.
* xcofflink.c (xcoff_find_tc0): Update bfd_xcoff_put_symbol_name call.
(xcoff_write_global_symbol): Likewise.
(xcoff_link_input_bfd): Test info->traditional_format rather than
BFD_TRADITIONAL_FORMAT flag.
* cofflink.c (_bfd_coff_final_link): Likewise.
(_bfd_coff_link_input_bfd, _bfd_coff_write_global_sym): Likewise.
* elf32-arc.c (ARC_ELF_HOWTO): Delete.
(arc_elf_howto): New function.
(bfd_elf32_bfd_reloc_type_lookup): Use it in place of existing
init code.
(bfd_elf32_bfd_reloc_name_lookup): Use arc_elf_howto.
(arc_info_to_howto_rel, elf_arc_relocate_section): Likwise.
(elf_arc_check_relocs): Likewise.
This initialises howto.dst_mask so that relocations in debug sections
are applied by the generic reloc processing used by objdump to display
debug sections.
* elf32-arc.c (arc_elf_howto_init): Init dst_mask.
This patch removes too simple implementations of the breakpoint_reinsert_addr
operation.
The only reason to keep them around was to support thread events when
PTRACE_EVENT_CLONE was not present but this support has been removed in a
previous patch.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-{native,extended} / { -marm -mthumb }
Also compilation was tested on aarch64, bfin, cris, crisv32,
m32r, mips, nios2, ppc, s390, sparc, tic6x, tile, xtensa.
gdb/gdbserver/ChangeLog:
* linux-arm-low.c (arm_reinsert_addr): Remove function.
(struct linux_target_ops <breakpoint_reinsert_addr>: Set to NULL.
* linux-cris-low.c (cris_reinsert_addr> Remove function.
(struct linux_target_ops) <breakpoint_reinsert_addr>: Set to NULL.
* linux-crisv32-low.c (cris_reinsert_addr): Remove function.
(struct linux_target_ops) <breakpoint_reinsert_addr>: Set to NULL.
* linux-mips-low.c (mips_reinsert_addr): Remove function.
(struct linux_target_ops) <breakpoint_reinsert_addr>: Set to NULL.
* linux-nios2-low.c (nios2_reinsert_addr): Remove function.
(struct linux_target_ops) <breakpoint_reinsert_addr>: Set to NULL.
* linux-sparc-low.c (sparc_reinsert_addr): Remove function.
(struct linux_target_ops) <breakpoint_reinsert_addr>: Set to NULL.
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.
When testing with "target remote" with "maint set target-non-stop on",
we regressions like this:
Running /home/pedro/gdb/mygit/build/../src/gdb/testsuite/gdb.threads/continue-pending-after-query.exp ...
FAIL: gdb.threads/continue-pending-after-query.exp: iter 4: continue until exit
FAIL: gdb.threads/continue-pending-after-query.exp: iter 6: continue until exit
FAIL: gdb.threads/continue-pending-after-query.exp: iter 10: continue until exit
=== gdb Summary ===
# of expected passes 28
# of unexpected failures 3
where gdb.log shows:
continue
Continuing.
Remote communication error. Target disconnected.: Connection reset by peer.
(gdb) FAIL: gdb.threads/continue-pending-after-query.exp: iter 4: continue until exit
Enabling gdb + gdbserver debug logs we see:
gdbserver: <<<< exiting linux_wait_1
gdbserver: handling possible serial event
gdbserver: Writing resume reply for LWP 11089.11089:0
gdbserver: handling possible serial event
gdbserver: GDBserver exiting
GDB: Packet received: OK
GDB: infrun: prepare_to_wait
GDB: Sending packet: $vStopped#55...Packet received: W0;process:2b51
GDB: Sending packet: $vStopped#55...Packet received: OK
GDB: infrun: target_wait (-1.0.0, status) =
GDB: infrun: -1.0.0 [Thread 0],
GDB: infrun: status->kind = no-resumed
GDB: Sending packet: $Hgp2b51.2b51#41...Remote connection closed
(gdb) FAIL: gdb.threads/continue-pending-after-query.exp: iter 1: continue until exit
Notice the "Packet received: W0;process:2b51" followed by
vStopped->OK.
That means the process exit notification was successfully sent to GDB
and GDB fetched it. That makes gdbserver exit, in
server.c:process_serial_event:
if (!extended_protocol && have_ran && !target_running ())
{
/* In non-stop, defer exiting until GDB had a chance to query
the whole vStopped list (until it gets an OK). */
if (QUEUE_is_empty (notif_event_p, notif_stop.queue))
{
/* Be transparent when GDB is connected through stdio -- no
need to spam GDB's console. */
if (!remote_connection_is_stdio ())
fprintf (stderr, "GDBserver exiting\n");
remote_close ();
exit (0);
}
}
However, GDB is still busy processing an earlier "no-resumed" event,
and sends a "Hg" packet, which errors out with "Remote connection
closed". IOW, it's not enough to wait for GDB to query the whole
vStopped list, gdbserver needs to wait until the exit event is really
processed.
The fix is to make gdbserver not disconnect until gdb does.
Tested on x86_64 Fedora, native gdbserver, remote + extended-remote +
with and without "maint set target-non-stop on".
gdb/gdbserver/ChangeLog:
2015-10-14 Pedro Alves <palves@redhat.com>
* remote-utils.c (readchar): Don't print "Got EOF" unless
debugging gdbserver.
* server.c (captured_main): Exit gdbserver if gdb disconnects when
in "target remote" mode and there are no processes left to debug.
(process_serial_event): Remove 'have_ran' static local and remove
logic that exits gdbserver in "target remote" mode.
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.
Say GDB wants to access the inferior process's memory. The current
remote general thread is 3, but GDB's switched to thread 2. Because
both threads are of the same process, GDB skips making the remote
thread be thread 2 as well (sending an Hg packet) before accessing
memory (remote.c:set_general_process). However, if thread 3 has
exited meanwhile, thread 3 no longer exists on the server and
gdbserver points current_thread to NULL. The result is the memory
access fails, even through the process still exists.
Fix this by making prepare_to_access memory select the thread to
access memory through.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* mem-break.c (check_gdb_bp_preconditions): Remove current_thread
check.
(set_gdb_breakpoint): If prepare_to_access_memory fails, set *ERR
to -1.
* target.c (struct thread_search): New structure.
(thread_search_callback): New function.
(prev_general_thread): New global.
(prepare_to_access_memory, done_accessing_memory): New functions.
* target.h (prepare_to_access_memory, done_accessing_memory):
Replace macros with function declarations.
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.
Running the testsuite against gdbserver with "maint set target-non-stop on"
stumbled on a set of problems. See code comments for details.
This handles my concerns expressed in PR14618.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
PR 14618
* infrun.c (handle_no_resumed): New function.
(handle_inferior_event_1) <TARGET_WAITKIND_NO_RESUMED>: Defer to
handle_no_resumed.
The range-stepping tests fail with "maint set target-non-stop on" mode
because exec_cmd_expect_vCont_count doesn't know that in non-stop
mode, vCont's reply is simply "OK".
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* lib/range-stepping-support.exp (exec_cmd_expect_vCont_count):
Handle non-stop mode vCont replies.
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.
Testing with the extended-remote board with "maint set target-non-stop
on" shows a dprintf-non-stop.exp regression. The issue is simply that
the test is expecting output that is only valid for the native target:
native:
[process 8676] #1 stopped.
remote:
[Thread 8900.8900] #1 stopped.
In order to expose this without "maint set target-non-stop on", this
restarts gdb with non-stop mode already enabled.
gdb/testsuite/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.base/dprintf-non-stop.exp: Use build_executable instead of
prepare_for_testing. Start gdb with "set non-stop on" appended to
GDBFLAGS. Lax expected stop output.
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.
There's currently no non-stop equivalent of the all-stop ^C (\003)
"packet" that GDB sends when a ctrl-c is pressed while a foreground
command is active. There's vCont;t, but that's defined to cause a
"signal 0" stop.
This fixes many tests that type ^C, when testing with extended-remote
with "maint set target-non-stop on". E.g.:
Continuing.
talk to me baby
PASS: gdb.base/interrupt.exp: process is alive
a
a
PASS: gdb.base/interrupt.exp: child process ate our char
^C
[Thread 22730.22730] #1 stopped.
0x0000003615ee6650 in __read_nocancel () at ../sysdeps/unix/syscall-template.S:81
81 T_PSEUDO (SYSCALL_SYMBOL, SYSCALL_NAME, SYSCALL_NARGS)
(gdb) FAIL: gdb.base/interrupt.exp: send_gdb control C
p func1 ()
gdb/
2015-11-30 Pedro Alves <palves@redhat.com>
* NEWS (New remote packets): Mention vCtrlC.
* remote.c (PACKET_vCtrlC): New enum value.
(async_remote_interrupt): Call target_interrupt instead of
target_stop.
(remote_interrupt_as): Remove 'ptid' parameter.
(remote_interrupt_ns): New function.
(remote_stop): Adjust.
(remote_interrupt): If the target is in non-stop mode, try
interrupting with vCtrlC.
(initialize_remote): Install set remote ctrl-c packet.
gdb/doc/
2015-11-30 Pedro Alves <palves@redhat.com>
* gdb.texinfo (Bootstrapping): Add "interrupting remote targets"
anchor.
(Packets): Document vCtrlC.
gdb/gdbserver/
2015-11-30 Pedro Alves <palves@redhat.com>
* server.c (handle_v_requests): Handle vCtrlC.
Running local-watch-wrong-thread.exp with "maint set target-non-stop
on" exposes that gdb/remote.c only records whether the target stopped
for a breakpoint/watchpoint plus the watchpoint data address *for the
last reported remote event*. But in non-stop mode, we need to keep
that info per-thread, as each thread can end up with its own
last-status pending.
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* remote.c (struct remote_state) <remote_watch_data_address,
stop_reason>: Delete fields.
(struct private_thread_info) <stop_reason, watch_data_address>:
New fields.
(resume_clear_thread_private_info): New function.
(append_pending_thread_resumptions): Call it.
(remote_resume): Clear all threads' private info.
(process_stop_reply): Adjust.
(remote_wait_as): Don't reference remote_state's stop_reason
field.
(remote_stopped_by_sw_breakpoint)
(remote_stopped_by_hw_breakpoint, remote_stopped_by_watchpoint)
(remote_stopped_data_address): Adjust to refer get data from the
current thread.
This fixes a gdbserver crash when running
gdb.threads/non-ldr-exc-1.exp with "maint set target-non-stop on".
The problem is that qSymbol is called when gdbserver has
current_thread == NULL.
gdb/gdbserver/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* gdbthread.h (find_any_thread_of_pid): Declare.
* inferiors.c (thread_of_pid, find_any_thread_of_pid): New
functions.
* server.c (handle_query): If current_thread is NULL, look for
another thread of the selected process.
When running with "maint set target-non-stop on", and in all-stop
mode, nothing is stopping all threads after attaching. vAttach in
non-stop can leave all threads running and GDB has to explicitly pause
them.
This is not visible with the native target, as in that case, attach
always stops all threads (the core re-resumes them in case of
"attach&").
In addition, it's not defined which thread manages to report the
initial attach stop, so always pick the lowest one (otherwise
multi-attach.exp regresses).
gdb/ChangeLog:
2015-11-30 Pedro Alves <palves@redhat.com>
* infcmd.c (attach_post_wait): If the target is always in non-stop
mode, and the UI is in all-stop mode, stop all threads and pick
the one with lowest number as current.
This is the first pass at implementing support for all-stop mode
running against the remote target using the non-stop variant of the
protocol.
The trickiest part here is the initial connection setup/synching. We
need to fetch all inferiors' target descriptions etc. before stopping
threads, because stop_all_threads needs to read the threads' registers
(to record each thread's stop_pc). But OTOH, the initial inferior
setup (target_post_attach, post_create_inferior, etc.), only works
correctly if the inferior is stopped... So I've split that initial
setup part from attach_command_post_wait to a separate function, and
added a "still needs setup" flag to the inferior structure. This is
similar to gdbserver/linux-low.c's handling of discovering the
process's target description). Then if on connection all threads of
the remote inferior are running, when we go about stopping them, as
soon as they stop we call setup_inferior, from within
stop_all_threads.
Also, in all-stop, we need to process all the initial stop replies to
learn about all the pending signal the threads may already be stopped
for, and pick the one to report as current. This is exposed by
gdb.threads/reconnect-signal.exp.
gdb/
2015-11-30 Pedro Alves <palves@redhat.com>
* gdbthread.h (switch_to_thread_no_regs): Declare.
* infcmd.c (setup_inferior): New function, factored out from ...
(attach_command_post_wait): ... this. Rename to ...
(attach_post_wait): ... this. Replace parameter async_exec with
attach_post_wait_mode parameter. Adjust.
(enum attach_post_wait_mode): New enum.
(struct attach_command_continuation_args): Replace 'async_exec'
field with 'mode' field.
(attach_command_continuation): Adjust.
(attach_command): Add comment. Mark the inferior as needing
setup. Adjust to use enum attach_post_wait_mode.
(notice_new_inferior): Use switch_to_thread_no_regs. Adjust to
use enum attach_post_wait_mode.
* inferior.h (setup_inferior): Declare.
(struct inferior) <needs_setup>: New field.
* infrun.c (set_last_target_status): Make extern.
(stop_all_threads): Make extern. Setup inferior, if necessary.
* infrun.h (set_last_target_status, stop_all_threads): Declare.
* remote-notif.c (remote_async_get_pending_events_handler)
(handle_notification): Replace non_stop checks with
target_is_non_stop_p() checks.
* remote.c (remote_notice_new_inferior): Remove non_stop check.
(remote_update_thread_list): Replace non_stop check with
target_is_non_stop_p() check.
(print_one_stopped_thread): New function.
(process_initial_stop_replies): New 'from_tty' parameter.
"Notice" all new live inferiors after storing initial stops as
pending status in each corresponding thread. If all-stop, stop
all threads, try picking a signalled thread as current, and print
the status of that one thread. Record the last target status.
(remote_start_remote): Replace non_stop checks with
target_is_non_stop_p() checks. Don't query for the remote current
thread of use qOffsets here. Pass from_tty to
process_initial_stop_replies.
(extended_remote_attach): Replace non_stop checks with
target_is_non_stop_p() checks.
(extended_remote_post_attach): Send qOffsets here.
(remote_vcont_resume, remote_resume, remote_stop)
(remote_interrupt, remote_parse_stop_reply, remote_wait): Replace
non_stop checks with target_is_non_stop_p() checks.
(remote_async): If target is non-stop, mark/clear the pending
events token.
* thread.c (switch_to_thread_no_regs): New function.
