This commit moves the entire body of both GDB's and gdbserver's
x86_linux_prepare_to_resume functions into new functions,
x86_linux_update_debug_registers. This reorganisation allows
all Linux x86 low-level debug register code to be placed in one
shared file, separate from general Linux x86 shared code.
gdb/ChangeLog:
* x86-linux-nat.c (x86_linux_update_debug_registers):
New function, factored out from...
(x86_linux_prepare_to_resume): ...this.
gdb/gdbserver/ChangeLog:
* linux-x86-low.c (x86_linux_update_debug_registers):
New function, factored out from...
(x86_linux_prepare_to_resume): ...this.
This commit makes several small changes to the low-level debug
register code for Linux x86, making the code in the GDB and
gdbserver implementations identical.
gdb/ChangeLog:
* x86-linux-nat.c (x86_linux_dr_set_addr): Update assertion.
(x86_linux_new_thread): Rename argument.
gdb/gdbserver/ChangeLog:
* linux-x86-low.c (x86_linux_dr_get): Add assertion.
Use perror_with_name. Pass string through gettext.
(x86_linux_dr_set): Likewise.
This commit renames gdbserver's low-level Linux x86 debug register
accessors to the same names used by GDB.
gdb/gdbserver/ChangeLog:
* linux-x86-low.c (x86_dr_low_set_addr): Rename to...
(x86_linux_dr_set_addr): ...this.
(x86_dr_low_get_addr): Rename to...
(x86_linux_dr_get_addr): ...this.
(x86_dr_low_set_control): Rename to...
(x86_linux_dr_set_control): ...this.
(x86_dr_low_get_control): Rename to...
(x86_linux_dr_get_control): ...this.
(x86_dr_low_get_status): Rename to...
(x86_linux_dr_get_status): ...this.
(x86_dr_low): Update with new function names.
This commit moves the code to handle lwp_info.arch_private for
Linux x86 into a new shared file, nat/x86-linux.c.
gdb/ChangeLog:
* nat/x86-linux.h: New file.
* nat/x86-linux.c: Likewise.
* Makefile.in (HFILES_NO_SRCDIR): Add nat/x86-linux.h.
(x86-linux.o): New rule.
* config/i386/linux.mh (NATDEPFILES): Add x86-linux.o.
* config/i386/linux64.mh (NATDEPFILES): Likewise.
* nat/linux-nat.h (struct arch_lwp_info): New forward declaration.
(lwp_set_arch_private_info): New declaration.
(lwp_arch_private_info): Likewise.
* linux-nat.c (lwp_set_arch_private_info): New function.
(lwp_arch_private_info): Likewise.
* x86-linux-nat.c: Include nat/x86-linux.h.
(arch_lwp_info): Removed structure.
(update_debug_registers_callback):
Use lwp_set_debug_registers_changed.
(x86_linux_prepare_to_resume): Use lwp_debug_registers_changed
and lwp_set_debug_registers_changed.
(x86_linux_new_thread): Use lwp_set_debug_registers_changed.
gdb/gdbserver/ChangeLog:
* Makefile.in (x86-linux.o): New rule.
* configure.srv: Add x86-linux.o to relevant targets.
* linux-low.c (lwp_set_arch_private_info): New function.
(lwp_arch_private_info): Likewise.
* linux-x86-low.c: Include nat/x86-linux.h.
(arch_lwp_info): Removed structure.
(update_debug_registers_callback):
Use lwp_set_debug_registers_changed.
(x86_linux_prepare_to_resume): Use lwp_debug_registers_changed
and lwp_set_debug_registers_changed.
(x86_linux_new_thread): Use lwp_set_debug_registers_changed.
This commit changes the signature of linux_target_ops.new_thread in
gdbserver to match that used in GDB's equivalent.
gdb/gdbserver/ChangeLog:
* linux-low.h (linux_target_ops) <new_thread>: Changed signature.
* linux-arm-low.c (arm_new_thread): Likewise.
* linux-aarch64-low.c (aarch64_linux_new_thread): Likewise.
* linux-mips-low.c (mips_linux_new_thread): Likewise.
* linux-x86-low.c (x86_linux_new_thread): Likewise.
* linux-low.c (add_lwp): Update the_low_target.new_thread call.
This commit introduces three accessors that shared Linux code can
use to access fields of struct lwp_info. The GDB and gdbserver
Linux x86 code is modified to use them.
gdb/ChangeLog:
* nat/linux-nat.h (ptid_of_lwp): New declaration.
(lwp_is_stopped): Likewise.
(lwp_stop_reason): Likewise.
* linux-nat.c (ptid_of_lwp): New function.
(lwp_is_stopped): Likewise.
(lwp_is_stopped_by_watchpoint): Likewise.
* x86-linux-nat.c (update_debug_registers_callback):
Use lwp_is_stopped.
(x86_linux_prepare_to_resume): Use ptid_of_lwp and
lwp_stop_reason.
gdb/gdbserver/ChangeLog:
* linux-low.c (ptid_of_lwp): New function.
(lwp_is_stopped): Likewise.
(lwp_stop_reason): Likewise.
* linux-x86-low.c (update_debug_registers_callback):
Use lwp_is_stopped.
(x86_linux_prepare_to_resume): Use ptid_of_lwp and
lwp_stop_reason.
Both GDB and gdbserver had linux_stop_lwp functions with identical
declarations. This commit moves these to nat/linux-nat.h to allow
shared code to use the function.
gdb/ChangeLog:
* linux-nat.h (linux_stop_lwp): Move declaration to...
* nat/linux-nat.h (linux_stop_lwp): New declaration.
gdb/gdbserver/ChangeLog:
* linux-low.h (linux_stop_lwp): Remove declaration.
This commit introduces a new function, iterate_over_lwps, that
shared Linux code can use to call a function for each LWP that
matches certain criteria. This function already existed in GDB
and was in use by GDB's various low-level Linux x86 debug register
setters. An equivalent was written for gdbserver and gdbserver's
low-level Linux x86 debug register setters were modified to use
it.
gdb/ChangeLog:
* linux-nat.h: Include nat/linux-nat.h.
(iterate_over_lwps): Move declaration to nat/linux-nat.h.
* nat/linux-nat.h (struct lwp_info): New forward declaration.
(iterate_over_lwps_ftype): New typedef.
(iterate_over_lwps): New declaration.
* linux-nat.h (iterate_over_lwps): Update comment. Use
iterate_over_lwps_ftype. Update callback return value check.
gdb/gdbserver/ChangeLog:
* linux-low.h: Include nat/linux-nat.h.
* linux-low.c (iterate_over_lwps_args): New structure.
(iterate_over_lwps_filter): New function.
(iterate_over_lwps): Likewise.
* linux-x86-low.c (update_debug_registers_callback):
Update signature to what iterate_over_lwps expects.
Remove PID check that iterate_over_lwps now performs.
(x86_dr_low_set_addr): Use iterate_over_lwps.
(x86_dr_low_set_control): Likewise.
This commit introduces a new function, x86_debug_reg_state, that
shared x86 code can use to access the local mirror of a process's
debug registers. This function already existed in GDB and was
in use by GDB's x86_linux_prepare_to_resume. An equivalent was
written for gdbserver and gdbserver's x86_linux_prepare_to_resume
was modified to use it.
gdb/ChangeLog:
* x86-nat.h (x86_debug_reg_state): Move declaration to...
* nat/x86-dregs.h (x86_debug_reg_state): New declaration.
gdb/gdbserver/ChangeLog:
* linux-x86-low.c (x86_debug_reg_state): New function.
(x86_linux_prepare_to_resume): Use the above.
This commit introduces a new function, current_lwp_ptid, that
shared Linux code can use to obtain the ptid of the current
lightweight process.
gdb/ChangeLog:
* nat/linux-nat.h (current_lwp_ptid): New declaration.
* linux-nat.c (current_lwp_ptid): New function.
* x86-linux-nat.c: Include nat/linux-nat.h.
(x86_linux_dr_get_addr): Use current_lwp_ptid.
(x86_linux_dr_get_control): Likewise.
(x86_linux_dr_get_status): Likewise.
(x86_linux_dr_set_control): Likewise.
(x86_linux_dr_set_addr): Likewise.
gdb/gdbserver/ChangeLog:
* linux-low.c (current_lwp_ptid): New function.
* linux-x86-low.c: Include nat/linux-nat.h.
(x86_dr_low_get_addr): Use current_lwp_ptid.
(x86_dr_low_get_control): Likewise.
(x86_dr_low_get_status): Likewise.
On GNU/Linux, this test sometimes FAILs like this:
(gdb) run
Starting program: /home/pedro/gdb/mygit/build/gdb/testsuite/gdb.threads/killed
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/lib64/libthread_db.so.1".
ptrace: No such process.
(gdb)
Program terminated with signal SIGKILL, Killed.
The program no longer exists.
FAIL: gdb.threads/killed.exp: run program to completion (timeout)
Note the suspicious "No such process" line (that's errno==ESRCH).
Adding debug output we see:
linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 18465, ERRNO-OK
LLW: waitpid 18465 received Stopped (signal) (stopped)
LNW: waitpid(-1, ...) returned 18461, ERRNO-OK
LLW: waitpid 18461 received Trace/breakpoint trap (stopped)
LLW: Handling extended status 0x03057f
LHEW: Got clone event from LWP 18461, new child is LWP 18465
LNW: waitpid(-1, ...) returned 0, ERRNO-OK
RSRL: resuming stopped-resumed LWP LWP 18465 at 0x3b36af4b51: step=0
RSRL: resuming stopped-resumed LWP LWP 18461 at 0x3b36af4b51: step=0
sigchld
ptrace: No such process.
(gdb) linux_nat_wait: [process -1], [TARGET_WNOHANG]
LLW: enter
LNW: waitpid(-1, ...) returned 18465, ERRNO-OK
LLW: waitpid 18465 received Killed (terminated)
LLW: LWP 18465 exited.
LNW: waitpid(-1, ...) returned 18461, No child processes
LLW: waitpid 18461 received Killed (terminated)
Process 18461 exited
LNW: waitpid(-1, ...) returned -1, No child processes
LLW: exit
sigchld
infrun: target_wait (-1, status) =
infrun: 18461 [process 18461],
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
FAIL: gdb.threads/killed.exp: run program to completion (timeout)
The issue is that here:
RSRL: resuming stopped-resumed LWP LWP 18465 at 0x3b36af4b51: step=0
RSRL: resuming stopped-resumed LWP LWP 18461 at 0x3b36af4b51: step=0
The first line shows we had just resumed LWP 18465, which does:
void *
child_func (void *dummy)
{
kill (pid, SIGKILL);
exit (1);
}
So if the kernel manages to schedule that thread fast enough, the
process may be killed before GDB has a chance to resume LWP 18461.
GDBserver has code at the tail end of linux_resume_one_lwp to cope
with this:
~~~
ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, lwpid_of (thread),
(PTRACE_TYPE_ARG3) 0,
/* Coerce to a uintptr_t first to avoid potential gcc warning
of coercing an 8 byte integer to a 4 byte pointer. */
(PTRACE_TYPE_ARG4) (uintptr_t) signal);
current_thread = saved_thread;
if (errno)
{
/* ESRCH from ptrace either means that the thread was already
running (an error) or that it is gone (a race condition). If
it's gone, we will get a notification the next time we wait,
so we can ignore the error. We could differentiate these
two, but it's tricky without waiting; the thread still exists
as a zombie, so sending it signal 0 would succeed. So just
ignore ESRCH. */
if (errno == ESRCH)
return;
perror_with_name ("ptrace");
}
~~~
However, that's not a complete fix, because between starting to handle
the resume request and getting that PTRACE_CONTINUE, we run other
ptrace calls that can also fail with ESRCH, and that end up throwing
an error (with perror_with_name).
In the case above, I indeed sometimes see resume_stopped_resumed_lwps
fail in the registers read:
resume_stopped_resumed_lwps (struct lwp_info *lp, void *data)
{
...
CORE_ADDR pc = regcache_read_pc (regcache);
Or e.g., in 32-bit mode, i386_linux_resume has several calls that can
throw too.
Whether to ignore ptrace errors or not depends on context that is only
available somewhere up the call chain. So the fix is to let ptrace
errors throw as they do today, and wrap the resume request in a
TRY/CATCH that swallows it iff the lwp that we were trying to resume
is no longer ptrace-stopped.
gdb/gdbserver/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_resume_one_lwp): Rename to ...
(linux_resume_one_lwp_throw): ... this. Don't handle ESRCH here,
instead call perror_with_name.
(check_ptrace_stopped_lwp_gone): New function.
(linux_resume_one_lwp): Reimplement as wrapper around
linux_resume_one_lwp_throw that swallows errors if the LWP is
gone.
gdb/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_resume_one_lwp): Rename to ...
(linux_resume_one_lwp_throw): ... this. Don't handle ESRCH here,
instead call perror_with_name.
(check_ptrace_stopped_lwp_gone): New function.
(linux_resume_one_lwp): Reimplement as wrapper around
linux_resume_one_lwp_throw that swallows errors if the LWP is
gone.
(resume_stopped_resumed_lwps): Try register reads in TRY/CATCH and
swallows errors if the LWP is gone. Use
linux_resume_one_lwp_throw instead of linux_resume_one_lwp.
The previous change added an assertion that is catching yet another
bug in count_events_callback/select_event_lwp_callback:
(gdb)
PASS: gdb.mi/mi-nonstop.exp: interrupted
mi_expect_interrupt: expecting: \*stopped,(reason="signal-received",signal-name="0",signal-meaning="Signal 0"|reason="signal-received",signal-name="SIGINT",signal-meaning="Interrupt")[^
]*
/home/pedro/gdb/mygit/src/gdb/gdbserver/linux-low.c:2329: A problem internal to GDBserver has been detected.
select_event_lwp: Assertion `num_events > 0' failed.
=thread-group-exited,id="i1"
Certainly select_event_lwp_callback should always at least find one
event, as it's only called because an event triggered (though we may
have more than one: the point of the function is randomly picking
one).
An LWP that GDB previously asked to continue/step (thus is resumed)
and gets a vCont;t request ends up with last_resume_kind ==
resume_stop. These functions in gdbserver used to filter out events
that weren't going to be reported to GDB; I think the last_resume_kind
kind check used to make sense at that point, but it no longer does.
gdb/gdbserver/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-low.c (count_events_callback, select_event_lwp_callback):
No longer check whether the thread has resume_stop as last resume
kind.
Wanting to make sure the new continue-pending-status.exp test tests
both cases of threads 2 and 3 reporting an event, I added counters to
the test, to make it FAIL if events for both threads aren't seen.
Assuming a well behaved backend, and given a reasonable number of
iterations, it should PASS.
However, running that against GNU/Linux gdbserver, I found that
surprisingly, that FAILed. GDBserver always reported the breakpoint
hit for the same thread.
Turns out that I broke gdbserver's thread event randomization
recently, with git commit 582511be ([gdbserver] linux-low.c: better
starvation avoidance, handle non-stop mode too). In that commit I
missed that the thread structure also has a status_pending_p field...
The end result was that count_events_callback always returns 0, and
then if no thread is stepping, select_event_lwp always returns the
event thread. IOW, no randomization is happening at all. Quite
curious how all the other changes in that patch were sufficient to fix
non-stop-fair-events.exp anyway even with that broken.
Tested on x86_64 Fedora 20, native and gdbserver.
gdb/gdbserver/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-low.c (count_events_callback, select_event_lwp_callback):
Use the lwp's status_pending_p field, not the thread's.
gdb/testsuite/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* gdb.threads/continue-pending-status.exp (saw_thread_2)
(saw_thread_3): New globals.
(top level): Increment them when an event for the corresponding
thread is seen.
(no thread starvation): New test.
This function (in both GDB and GDBserver) used to consider only
SIGTRAP/breakpoint events, but that's no longer the case nowadays.
gdb/gdbserver/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-low.c (select_event_lwp_callback): Update comments to
no longer mention SIGTRAP.
gdb/ChangeLog:
2015-03-19 Pedro Alves <palves@redhat.com>
* linux-nat.c (select_event_lwp_callback): Update comment to no
longer mention SIGTRAP.
This commit makes support for the "vFile:fstat" packet be detected
by probing rather than using qSupported, for consistency with the
other vFile: packets.
gdb/ChangeLog:
(remote_protocol_features): Remove the "vFile:fstat" feature.
(remote_hostio_fstat): Probe for "vFile:fstat" support.
gdb/doc/ChangeLog:
* gdb.texinfo (General Query Packets): Remove documentation
for now-removed vFile:fstat qSupported features.
gdb/gdbserver/ChangeLog:
* server.c (handle_query): Do not report vFile:fstat as supported.
Fixes this in C++ mode:
gdb/gdbserver/tracepoint.c: In function ‘void* gdb_agent_helper_thread(void*)’:
gdb/gdbserver/tracepoint.c:7190:47: error: cannot convert ‘sockaddr_un*’ to ‘sockaddr*’ for argument ‘2’ to ‘int accept(int, sockaddr*, socklen_t*)’
fd = accept (listen_fd, &sockaddr, &tmp);
gdb/gdbserver/ChangeLog:
2015-03-09 Pedro Alves <palves@redhat.com>
* tracepoint.c (gdb_agent_helper_thread): Cast '&sockaddr' to
'struct sockaddr' pointer in 'accept' call.
This reverts 366c75fc.
We don't actually need to access the object through
"struct sockaddr *", so we don't need the union:
https://sourceware.org/ml/gdb-patches/2015-03/msg00213.html
gdb/ChangeLog:
2015-03-09 Pedro Alves <palves@redhat.com>
Revert:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/gdb_socket.h: New file.
* ser-tcp.c: Include gdb_socket.h. Don't include netinet/in.h nor
sys/socket.h.
(net_open): Use union gdb_sockaddr_u.
gdb/gdbserver/ChangeLog:
2015-03-09 Pedro Alves <palves@redhat.com>
Revert:
2015-03-07 Pedro Alves <palves@redhat.com>
* gdbreplay.c: No longer include <netinet/in.h>, <sys/socket.h>,
or <winsock2.h> here. Instead include "gdb_socket.h".
(remote_open): Use union gdb_sockaddr_u.
* remote-utils.c: No longer include <netinet/in.h>, <sys/socket.h>
or <winsock2.h> here. Instead include "gdb_socket.h".
(handle_accept_event, remote_prepare): Use union gdb_sockaddr_u.
* tracepoint.c: Include "gdb_socket.h" instead of <sys/socket.h>
or <sys/un.h>.
(init_named_socket, gdb_agent_helper_thread): Use union
gdb_sockaddr_u.
Whoops, these are C specific, but I somehow missed the warnings before:
cc1plus: warning: command line option ‘-Wmissing-prototypes’ is valid for C/ObjC but not for C++ [enabled by default]
cc1plus: warning: command line option ‘-Wdeclaration-after-statement’ is valid for C/ObjC but not for C++ [enabled by default]
cc1plus: warning: command line option ‘-Wmissing-parameter-type’ is valid for C/ObjC but not for C++ [enabled by default]
cc1plus: warning: command line option ‘-Wold-style-declaration’ is valid for C/ObjC but not for C++ [enabled by default]
cc1plus: warning: command line option ‘-Wold-style-definition’ is valid for C/ObjC but not for C++ [enabled by default]
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* configure.ac (build_warnings): Move -Wmissing-prototypes
-Wdeclaration-after-statement -Wmissing-parameter-type
-Wold-style-declaration -Wold-style-definition to the C-specific
set.
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* configure.ac (build_warnings): Move
-Wdeclaration-after-statement to the C-specific set.
* configure: Regenerate.
Building gdbserver in C++ mode shows:
gdb/gdbserver/tracepoint.c: In function ‘void* gdb_agent_helper_thread(void*)’:
gdb/gdbserver/tracepoint.c:7190:47: error: cannot convert ‘sockaddr_un*’ to ‘sockaddr*’ for argument ‘2’ to ‘int accept(int, sockaddr*, socklen_t*)’
fd = accept (listen_fd, &sockaddr, &tmp);
A few places in the tree already have an explicit cast to struct
sockaddr *, but that's a strict aliasing violation. Instead of
propagating invalid code, fix this by using a union instead.
gdb/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* common/gdb_socket.h: New file.
* ser-tcp.c: Include gdb_socket.h. Don't include netinet/in.h nor
sys/socket.h.
(net_open): Use union gdb_sockaddr_u.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
* gdbreplay.c: No longer include <netinet/in.h>, <sys/socket.h>,
or <winsock2.h> here. Instead include "gdb_socket.h".
(remote_open): Use union gdb_sockaddr_u.
* remote-utils.c: No longer include <netinet/in.h>, <sys/socket.h>
or <winsock2.h> here. Instead include "gdb_socket.h".
(handle_accept_event, remote_prepare): Use union gdb_sockaddr_u.
* tracepoint.c: Include "gdb_socket.h" instead of <sys/socket.h>
or <sys/un.h>.
(init_named_socket, gdb_agent_helper_thread): Use union
gdb_sockaddr_u.
This patch splits the TRY_CATCH macro into three, so that we go from
this:
~~~
volatile gdb_exception ex;
TRY_CATCH (ex, RETURN_MASK_ERROR)
{
}
if (ex.reason < 0)
{
}
~~~
to this:
~~~
TRY
{
}
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
~~~
Thus, we'll be getting rid of the local volatile exception object, and
declaring the caught exception in the catch block.
This allows reimplementing TRY/CATCH in terms of C++ exceptions when
building in C++ mode, while still allowing to build GDB in C mode
(using setjmp/longjmp), as a transition step.
TBC, after this patch, is it _not_ valid to have code between the TRY
and the CATCH blocks, like:
TRY
{
}
// some code here.
CATCH (ex, RETURN_MASK_ERROR)
{
}
END_CATCH
Just like it isn't valid to do that with C++'s native try/catch.
By switching to creating the exception object inside the CATCH block
scope, we can get rid of all the explicitly allocated volatile
exception objects all over the tree, and map the CATCH block more
directly to C++'s catch blocks.
The majority of the TRY_CATCH -> TRY+CATCH+END_CATCH conversion was
done with a script, rerun from scratch at every rebase, no manual
editing involved. After the mechanical conversion, a few places
needed manual intervention, to fix preexisting cases where we were
using the exception object outside of the TRY_CATCH block, and cases
where we were using "else" after a 'if (ex.reason) < 0)' [a CATCH
after this patch]. The result was folded into this patch so that GDB
still builds at each incremental step.
END_CATCH is necessary for two reasons:
First, because we name the exception object in the CATCH block, which
requires creating a scope, which in turn must be closed somewhere.
Declaring the exception variable in the initializer field of a for
block, like:
#define CATCH(EXCEPTION, mask) \
for (struct gdb_exception EXCEPTION; \
exceptions_state_mc_catch (&EXCEPTION, MASK); \
EXCEPTION = exception_none)
would avoid needing END_CATCH, but alas, in C mode, we build with C90,
which doesn't allow mixed declarations and code.
Second, because when TRY/CATCH are wired to real C++ try/catch, as
long as we need to handle cleanup chains, even if there's no CATCH
block that wants to catch the exception, we need for stop at every
frame in the unwind chain and run cleanups, then rethrow. That will
be done in END_CATCH.
After we require C++, we'll still need TRY/CATCH/END_CATCH until
cleanups are completely phased out -- TRY/CATCH in C++ mode will
save/restore the current cleanup chain, like in C mode, and END_CATCH
catches otherwise uncaugh exceptions, runs cleanups and rethrows, so
that C++ cleanups and exceptions can coexist.
IMO, this still makes the TRY/CATCH code look a bit more like a
newcomer would expect, so IMO worth it even if we weren't considering
C++.
gdb/ChangeLog.
2015-03-07 Pedro Alves <palves@redhat.com>
* common/common-exceptions.c (struct catcher) <exception>: No
longer a pointer to volatile exception. Now an exception value.
<mask>: Delete field.
(exceptions_state_mc_init): Remove all parameters. Adjust.
(exceptions_state_mc): No longer pop the catcher here.
(exceptions_state_mc_catch): New function.
(throw_exception): Adjust.
* common/common-exceptions.h (exceptions_state_mc_init): Remove
all parameters.
(exceptions_state_mc_catch): Declare.
(TRY_CATCH): Rename to ...
(TRY): ... this. Remove EXCEPTION and MASK parameters.
(CATCH, END_CATCH): New.
All callers adjusted.
gdb/gdbserver/ChangeLog:
2015-03-07 Pedro Alves <palves@redhat.com>
Adjust all callers of TRY_CATCH to use TRY/CATCH/END_CATCH
instead.
I happen to see that show_debug_regs is used as an arithmetic type,
but it should be a boolean,
if (show_debug_regs > 1)
On the other hand, GDB RSP only allows setting it to either 0 or 1,
so it makes no sense to check whether it is greater than 1. This
patch fixes it.
gdb/gdbserver:
2015-03-06 Yao Qi <yao.qi@linaro.org>
* linux-aarch64-low.c (aarch64_insert_point): Use
show_debug_regs as a boolean.
(aarch64_remove_point): Likewise.
I forgot to update these target_ops instances when I added these new
hooks.
I confirmed mingw32-w64 builds again at least.
gdb/gdbserver/ChangeLog:
2015-03-05 Pedro Alves <palves@redhat.com>
* lynx-low.c (lynx_target_ops): Install NULL hooks for
stopped_by_sw_breakpoint, supports_stopped_by_sw_breakpoint,
stopped_by_hw_breakpoint, supports_stopped_by_hw_breakpoint.
* nto-low.c (nto_target_ops): Likewise.
* spu-low.c (spu_target_ops): Likewise.
* win32-low.c (win32_target_ops): Likewise.
This patch adjusts gdbserver's Linux backend to tell gdbserver core
(and ultimately GDB) whether a trap was caused by a breakpoint.
It teaches the backend to get that information out of the si_code of
the SIGTRAP siginfo.
gdb/gdbserver/ChangeLog:
2015-03-04 Pedro Alves <palves@redhat.com>
* linux-low.c (check_stopped_by_breakpoint) [USE_SIGTRAP_SIGINFO]:
Decide whether a breakpoint triggered based on the SIGTRAP's
siginfo.si_code.
(thread_still_has_status_pending_p) [USE_SIGTRAP_SIGINFO]: Don't check whether a
breakpoint is inserted if relying on SIGTRAP's siginfo.si_code.
(linux_low_filter_event): Check for breakpoints before checking
watchpoints.
(linux_wait_1): Don't re-increment the PC if relying on SIGTRAP's
siginfo.si_code.
(linux_stopped_by_sw_breakpoint)
(linux_supports_stopped_by_sw_breakpoint)
(linux_stopped_by_hw_breakpoint)
(linux_supports_stopped_by_hw_breakpoint): New functions.
(linux_target_ops): Install new target methods.
This patch teaches the core of gdbserver about the new "swbreak" and
"hwbreak" stop reasons, and adds the necessary hooks a backend needs
to implement to support the feature.
gdb/gdbserver/ChangeLog:
2015-03-04 Pedro Alves <palves@redhat.com>
* remote-utils.c (prepare_resume_reply): Report swbreak/hbreak.
* server.c (swbreak_feature, hwbreak_feature): New globals.
(handle_query) <qSupported>: Handle "swbreak+" and "hwbreak+".
(captured_main): Clear swbreak_feature and hwbreak_feature.
* server.h (swbreak_feature, hwbreak_feature): Declare.
* target.h (struct target_ops) <stopped_by_sw_breakpoint,
supports_stopped_by_sw_breakpoint, stopped_by_hw_breakpoint,
supports_stopped_by_hw_breakpoint>: New fields.
(target_supports_stopped_by_sw_breakpoint)
(target_stopped_by_sw_breakpoint)
(target_supports_stopped_by_hw_breakpoint)
(target_stopped_by_hw_breakpoint): Declare.
The heuristic for filtering out kernel addressess in BTS trace checks the
most significant bit in each address. This works fine for 32-bit and 64-bit
mode.
For 32-bit compatibility mode, i.e. a 32-bit inferior running on 64-bit
host, we need to check bit 63 (or any bit bigger than 31), not bit 31.
Use the machine field in struct utsname provided by a uname call to
determine whether we are running on a 64-bit host.
Thanks to Jan Kratochvil for reporting the issue.
gdb/
* nat/linux-btrace.c: Include sys/utsname.h.
(linux_determine_kernel_ptr_bits): New.
(linux_enable_bts): Call linux_determine_kernel_ptr_bits.
* x86-linux-nat.c (x86_linux_enable_btrace): Do not overwrite non-zero
ptr_bits.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Do not overwrite non-zero
ptr_bits.
On S/390 targets with vector registers, enable gdbserver to advertise
and handle the feature "org.gnu.gdb.s390.vx".
gdb/gdbserver/ChangeLog:
* Makefile.in (s390-vx-linux64.c, s390-tevx-linux64.c)
(s390x-vx-linux64.c, s390x-tevx-linux64.c): New rules.
(clean): Add "rm -f" for above C files.
* configure.srv (srv_regobj): Add s390-vx-linux64.o,
s390-tevx-linux64.o, s390x-vx-linux64.o, and s390x-tevx-linux64.o.
(srv_xmlfiles): Add s390-vx-linux64.xml, s390-tevx-linux64.xml,
s390x-vx-linux64.xml, s390x-tevx-linux64.xml, and s390-vx.xml.
* linux-s390-low.c (HWCAP_S390_VX): New macro.
(init_registers_s390_vx_linux64, init_registers_s390_tevx_linux64)
(init_registers_s390x_vx_linux64)
(init_registers_s390x_tevx_linux64)
(tdesc_s390_vx_linux64, tdesc_s390_tevx_linux64)
(tdesc_s390x_vx_linux64, tdesc_s390x_tevx_linux64): New extern
declarations.
(s390_fill_vxrs_low, s390_store_vxrs_low, s390_fill_vxrs_high)
(s390_store_vxrs_high): New functions.
(s390_regsets): Add entries for NT_S390_VXRS_LOW and
NT_S390_VXRS_HIGH.
(s390_arch_setup): Add logic for selecting one of the new target
descriptions. Activate the new vector regsets if applicable.
(initialize_low_arch): Also invoke init_registers_s390_vx_linux64,
init_registers_s390_tevx_linux64, init_registers_s390x_vx_linux64,
and init_registers_s390x_tevx_linux64.
Git commit 3c14e5a39b added a declaration for
gdb_agent_get_raw_reg to tracepoint.h, and this now caught that the
32-bit x86 implementation has the wrong prototype:
../../../src/gdb/gdbserver/linux-i386-ipa.c:103:1: error: conflicting types for ‘gdb_agent_get_raw_reg’
gdb_agent_get_raw_reg (unsigned char *raw_regs, int regnum)
^
In file included from ../../../src/gdb/gdbserver/linux-i386-ipa.c:24:0:
../../../src/gdb/gdbserver/tracepoint.h:168:31: note: previous declaration of ‘gdb_agent_get_raw_reg’ was here
IP_AGENT_EXPORT_FUNC ULONGEST gdb_agent_get_raw_reg
^
make[2]: *** [linux-i386-ipa.o] Error 1
gdb/gdbserver/
2015-03-01 Pedro Alves <palves@redhat.com>
* linux-i386-ipa.c (gdb_agent_get_raw_reg): Constify 'raw_regs'
parameter.
In C++ mode, we get:
gdb/gdbserver/linux-x86-low.c: In function ‘void x86_linux_dr_set(ptid_t, int, long unsigned int)’:
gdb/gdbserver/linux-x86-low.c:558:38: error: ‘regnum’ cannot appear in a constant-expression
offsetof (struct user, u_debugreg[regnum]), value);
^
gdb/gdbserver/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* linux-x86-low.c (u_debugreg_offset): New function.
(x86_linux_dr_get, x86_linux_dr_set): Use it.
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* x86-linux-nat.c (u_debugreg_offset): New function.
(x86_linux_dr_get, x86_linux_dr_set): Use it.
libthread_db.so calls symbols in the client (GDB), through the
proc-service interface. These routines must have extern "C" linkage
so their symbol names are not mangled when GDB is built as a C++
program. On the GDBserver side, we were missing fallback declarations for
all these symbols.
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* gdb_proc_service.h: Wrap with EXTERN_C_PUSH/EXTERN_C_POP.
gdb/gdbserver/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* gdb_proc_service.h: Wrap with EXTERN_C_PUSH/EXTERN_C_POP.
[!HAVE_PROC_SERVICE_H] (struct ps_prochandle): Forward declare.
[!HAVE_PROC_SERVICE_H] (ps_pdread, ps_pdwrite, ps_ptread)
ps_ptwrite, ps_lgetregs, ps_lsetregs, ps_lgetfpregs)
(ps_lsetfpregs, ps_getpid)
(ps_get_thread_area, ps_pglobal_lookup, ps_pstop, ps_pcontinue)
(ps_lstop, ps_lcontinue, ps_lgetxregsize, ps_lgetxregs)
(ps_lsetxregs, ps_plog): Declare.
Functions and variables that are exported by the IPA DSO (that
GDBserver needs to look up) should have "C" mangling, thus be declared
with extern "C".
Function and variable declarations need the extern "C" marker, but
variable definitions can't be marked extern, so the patch splits
IP_AGENT_EXPORT into three.
Building in C++ mode revealed that a few variables were missing
IP_AGENT_EXPORT, thus the IPA has been broken when stripped, even in C
mode... So this ends being a bug fix as well.
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* common/agent.h (IPA_SYM_EXPORTED_NAME): New.
(IPA_SYM): Use it.
* common/common-defs.h (EXTERN_C_PUSH, EXTERN_C_POP): New macros.
gdb/gdbserver/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* linux-amd64-ipa.c (gdb_agent_get_raw_reg): Use
IP_AGENT_EXPORT_FUNC.
* linux-i386-ipa.c (gdb_agent_get_raw_reg): Use
IP_AGENT_EXPORT_FUNC.
* tracepoint.c (ATTR_USED, ATTR_NOINLINE, ATTR_CONSTRUCTOR)
(IP_AGENT_EXPORT): Delete.
(gdb_tp_heap_buffer, gdb_jump_pad_buffer, gdb_jump_pad_buffer_end)
(gdb_trampoline_buffer, gdb_trampoline_buffer_end)
(gdb_trampoline_buffer_error, collecting, gdb_collect)
(stop_tracing, flush_trace_buffer, about_to_request_buffer_space)
(trace_buffer_is_full, stopping_tracepoint, expr_eval_result)
(error_tracepoint, tracepoints, tracing, trace_buffer_ctrl)
(trace_buffer_ctrl_curr, trace_buffer_lo, trace_buffer_hi)
(traceframe_read_count, traceframe_write_count)
(traceframes_created, trace_state_variables, get_raw_reg)
(get_trace_state_variable_value, set_trace_state_variable_value)
(ust_loaded, helper_thread_id, cmd_buf): Use
IPA_SYM_EXPORTED_NAME.
(stop_tracing, flush_trace_buffer): Use IP_AGENT_EXPORT_FUNC.
(tracepoints) Use IP_AGENT_EXPORT_VAR.
(stopping_tracepoint, trace_buffer_is_full, expr_eval_result): Use
IP_AGENT_EXPORT_VAR and wrap in EXTERN_C_PUSH/EXTERN_C_POP.
(last_tracepoint): Move into !IN_PROCESS_AGENT block.
(error_tracepoint): Use IP_AGENT_EXPORT_VAR and wrap in
EXTERN_C_PUSH/EXTERN_C_POP.
(trace_state_variables): Use IP_AGENT_EXPORT_VAR.
(trace_buffer_lo, trace_buffer_hi): Use IP_AGENT_EXPORT_VAR and
wrap in EXTERN_C_PUSH/EXTERN_C_POP.
(trace_buffer_ctrl, trace_buffer_ctrl_curr)
(traceframe_write_count, traceframe_read_count)
(traceframes_created, tracing): Use IP_AGENT_EXPORT_VAR.
(about_to_request_buffer_space, get_trace_state_variable_value)
(set_trace_state_variable_value): Use IP_AGENT_EXPORT_FUNC.
(collecting): Use IP_AGENT_EXPORT_VAR and wrap in
EXTERN_C_PUSH/EXTERN_C_POP.
(gdb_collect): Use IP_AGENT_EXPORT_FUNC.
(ust_loaded, cmd_buf): Use IP_AGENT_EXPORT_VAR.
(helper_thread_id, gdb_agent_capability): Use IP_AGENT_EXPORT_VAR
and wrap in EXTERN_C_PUSH/EXTERN_C_POP.
(gdb_tp_heap_buffer, gdb_jump_pad_buffer, gdb_jump_pad_buffer_end)
(gdb_trampoline_buffer, gdb_trampoline_buffer_end)
(gdb_trampoline_buffer_error): Use IP_AGENT_EXPORT_VAR.
* tracepoint.h (ATTR_USED, ATTR_NOINLINE, EXPORTED_SYMBOL):
Define.
(IP_AGENT_EXPORT_FUNC, IP_AGENT_EXPORT_VAR)
(IP_AGENT_EXPORT_VAR_DECL): Define.
(tracing): Declare.
(gdb_agent_get_raw_reg): Declare.
This patch renames symbols that happen to have names which are
reserved keywords in C++.
Most of this was generated with Tromey's cxx-conversion.el script.
Some places where later hand massaged a bit, to fix formatting, etc.
And this was rebased several times meanwhile, along with re-running
the script, so re-running the script from scratch probably does not
result in the exact same output. I don't think that matters anyway.
gdb/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
gdb/gdbserver/
2015-02-27 Tom Tromey <tromey@redhat.com>
Pedro Alves <palves@redhat.com>
Rename symbols whose names are reserved C++ keywords throughout.
This new option, disabled by default for now, allows specifying
whether to build GDB, GDBserver, and friends with a C++ (98/03)
compiler.
The name of the switch should be familiar to those who followed GCC's
own C++ conversion process.
. Adding -fpermissive to COMPILER in C++ mode (see the new
build-with-cxx.m4 file) makes errors like these be warnings instead:
gdb/infrun.c:6597:1: error: initializing argument 1 of ‘void sig_print_info(gdb_signal)’ [-fpermissive]
sig_print_info (enum gdb_signal oursig)
^
gdb/infrun.c: In function ‘void do_restore_infcall_suspend_state_cleanup(void*)’:
gdb/infrun.c:7164:39: error: invalid conversion from ‘void*’ to ‘infcall_suspend_state*’ [-fpermissive]
restore_infcall_suspend_state (state);
^
so that the compiler carries on compiling the file. -Werror still
catches the warnings, so nothing is lost, only our lifes are made
easier by concentrating on getting other more important things out of
the way first.
There's no way to quiet those warnings. Until they're all fixed, when
building in C++ mode, -Werror is disabled by default.
. Adding -Wno-narrowing suppresses thousands of instances of this warning:
gdb/arm-linux-tdep.c:439:1: error: narrowing conversion of ‘-1’ from ‘int’ to ‘ULONGEST {aka long unsigned int}’ inside { } is ill-formed in C++11 [-Werror=narrowing]
gdb/arm-linux-tdep.c:439:1: error: narrowing conversion of ‘-1l’ from ‘LONGEST {aka long int}’ to ‘ULONGEST {aka long unsigned int}’ inside { } is ill-formed in C++11 [-Werror=narrowing]
gdb/arm-linux-tdep.c:450:1: error: narrowing conversion of ‘-1’ from ‘int’ to ‘ULONGEST {aka long unsigned int}’ inside { } is ill-formed in C++11 [-Werror=narrowing]
We can defer handling those until we target C++11.
. Adding -Wno-sign-compare suppresses thousands of instances of this warning:
gdb/linux-record.c:1763:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
if (tmpulongest == tdep->fcntl_F_GETLK64)
^
. Adding -Wno-write-strings suppresses thousands of instances of this warning:
gdb/mi/mi-cmd-var.c: In function ‘void mi_cmd_var_show_attributes(char*, char**, int)’:
gdb/mi/mi-cmd-var.c:514:12: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]
attstr = "editable";
^
gdb/mi/mi-cmd-var.c:516:12: warning: deprecated conversion from string constant to ‘char*’ [-Wwrite-strings]
attstr = "noneditable";
^
For now, it's best to hide these warnings from view until we're
'-fpermissive'-clean, and can thus start building with -Werror.
The C compiler has always managed to build working GDBs with these
issues in the code, so a C++ compiler should too.
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* Makefile.in (COMPILER): New, get it from autoconf.
(COMPILE.pre, CC_LD): Use COMPILER.
(CXX): Get from autoconf instead.
(CXX_FOR_TARGET): Default to g++ instead of gcc.
* acinclude.m4: Include build-with-cxx.m4.
* build-with-cxx.m4: New file.
* configure.ac: Call AC_PROG_CXX and GDB_AC_BUILD_WITH_CXX.
Disable -Werror by default if building in C++ mode.
(build_warnings): Add -Wno-sign-compare, -Wno-write-strings and
-Wno-narrowing in C++ mode. Only enable -Wpointer-sign in C mode.
Run supported-warning-flags tests with the C++ compiler.
Save/restore CXXFLAGS too.
* configure: Regenerate.
gdb/gdbserver/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* Makefile.in (COMPILER): New, get it from autoconf.
(CXX): Get from autoconf instead.
(COMPILE.pre): Use COMPILER.
(CC-LD): Rename to ...
(CC_LD): ... this. Use COMPILER.
(gdbserver$(EXEEXT), gdbreplay$(EXEEXT), $(IPA_LIB)): Adjust.
(CXX_FOR_TARGET): Default to g++ instead of gcc.
* acinclude.m4: Include build-with-cxx.m4.
* configure.ac: Call AC_PROG_CXX and GDB_AC_BUILD_WITH_CXX.
Disable -Werror by default if building in C++ mode.
(build_warnings): Add -Wno-sign-compare, -Wno-write-strings and
-Wno-narrowing in C++ mode. Run supported-warning-flags tests with
the C++ compiler. Save/restore CXXFLAGS too.
* configure: Regenerate.
Converting GDB to be a C++ program, I stumbled on 'basename' issues,
like:
src/gdb/../include/ansidecl.h:169:64: error: new declaration ‘char* basename(const char*)’
/usr/include/string.h:597:26: error: ambiguates old declaration ‘const char* basename(const char*)’
which I believe led to this bit in gold's configure.ac:
dnl We have to check these in C, not C++, because autoconf generates
dnl tests which have no type information, and current glibc provides
dnl multiple declarations of functions like basename when compiling
dnl with C++.
AC_CHECK_DECLS([basename, ffs, asprintf, vasprintf, snprintf, vsnprintf, strverscmp])
These checks IIUC intend to generate all the HAVE_DECL_FOO symbols
that libiberty.h and ansidecl.h check.
GDB is missing these checks currently, which results in the conflict
shown above.
This adds an m4 file that both GDB and GDBserver's configury use to
pull in the autoconf checks that libiberty clients needs done in order
to use these libiberty.h/ansidecl.h.
gdb/ChangeLog:
2015-02-27 Pedro Alves <palves@redhat.com>
* libiberty.m4: New file.
* acinclude.m4: Include libiberty.m4.
* configure.ac: Call libiberty_INIT.
* config.in, configure: Regenerate.
gdb/gdbserver/
2015-02-27 Pedro Alves <palves@redhat.com>
* acinclude.m4: Include libiberty.m4.
* configure.ac: Call libiberty_INIT.
* config.in, configure: Regenerate.
.decr_pc_after_break is never higher than .breakpoint_len, so use
.breakpoint_len directly. Based on idea from Yao here:
https://sourceware.org/ml/gdb-patches/2015-02/msg00689.html
gdb/gdbserver/ChangeLog:
2015-02-26 Pedro Alves <palves@redhat.com>
* linux-low.c (linux_wait_1): When incrementing the PC past a
program breakpoint always use the_low_target.breakpoint_len as
increment, rather than the maximum between that and
the_low_target.decr_pc_after_break.
I'm going to add an alternate mechanism of breakpoint trap
identification to 'check_stopped_by_breakpoint' that does not rely on
checking the instruction at PC. The mechanism currently used to tell
whether we're stepping over a permanent breakpoint doesn't fit in that
new method. This patch redoes the whole logic in a different way that
works with both old and new methods, in essence moving the "stepped
permanent breakpoint" detection "one level up". It makes lower level
check_stopped_by_breakpoint always the adjust the PC, and then has
linux_wait_1 advance the PC past the breakpoint if necessary. This
ends up being better also because this now handles
non-decr_pc_after_break targets too. Before, such targets would get
stuck forever reexecuting the breakpoint instruction.
Tested on x86_64 Fedora 20.
gdb/gdbserver/ChangeLog:
2015-02-23 Pedro Alves <palves@redhat.com>
* linux-low.c (check_stopped_by_breakpoint): Don't check if the
thread was doing a step-over; always adjust the PC if
we stepped over a permanent breakpoint.
(linux_wait_1): If we stepped over breakpoint that was on top of a
permanent breakpoint, manually advance the PC past it.
$ make check RUNTESTFLAGS="--target_board=native-gdbserver/-m32 clone-thread_db.exp"
gdb.log shows:
Running target native-gdbserver/-m32
...
clone-thread_db: src/gdb/testsuite/gdb.threads/clone-thread_db.c:57: thread_fn: Assertion `res != -1' failed.
...
(gdb) FAIL: gdb.threads/clone-thread_db.exp: continue to end
That was waitpid returning -1 / EINTR. We don't see that when testing
with unix/-m32 (native debugging). Turns out to be that when
debugging a 32-bit inferior, a 64-bit GDBserver is reading/writing
$orig_eax from/to the wrong ptrace register buffer offset. When
gdbserver is 64-bit, the ptrace register buffer is in 64-bit layout,
so the register is found at "ORIG_EAX * 8", not at "ORIG_EAX * 4".
Fixes these with --target_board=native-gdbserver/-m32 on x86_64 Fedora 20:
-FAIL: gdb.threads/clone-thread_db.exp: continue to end
+PASS: gdb.threads/clone-thread_db.exp: continue to end
-FAIL: gdb.threads/hand-call-in-threads.exp: all dummies popped
+PASS: gdb.threads/hand-call-in-threads.exp: all dummies popped
PASS: gdb.threads/hand-call-in-threads.exp: breakpoint on all_threads_running
PASS: gdb.threads/hand-call-in-threads.exp: breakpoint on hand_call
PASS: gdb.threads/hand-call-in-threads.exp: disable scheduler locking
@@ -29339,15 +29331,15 @@ PASS: gdb.threads/hand-call-in-threads.e
PASS: gdb.threads/hand-call-in-threads.exp: discard hand call, thread 4
PASS: gdb.threads/hand-call-in-threads.exp: discard hand call, thread 5
PASS: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 1
-FAIL: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 2
-FAIL: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 3
-FAIL: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 4
+PASS: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 2
+PASS: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 3
+PASS: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 4
PASS: gdb.threads/hand-call-in-threads.exp: dummy stack frame number, thread 5
PASS: gdb.threads/hand-call-in-threads.exp: enable scheduler locking
PASS: gdb.threads/hand-call-in-threads.exp: hand call, thread 1
-FAIL: gdb.threads/hand-call-in-threads.exp: hand call, thread 2
-FAIL: gdb.threads/hand-call-in-threads.exp: hand call, thread 3
-FAIL: gdb.threads/hand-call-in-threads.exp: hand call, thread 4
+PASS: gdb.threads/hand-call-in-threads.exp: hand call, thread 2
+PASS: gdb.threads/hand-call-in-threads.exp: hand call, thread 3
+PASS: gdb.threads/hand-call-in-threads.exp: hand call, thread 4
PASS: gdb.threads/hand-call-in-threads.exp: hand call, thread 5
PASS: gdb.threads/hand-call-in-threads.exp: prepare to discard hand call, thread 1
PASS: gdb.threads/hand-call-in-threads.exp: prepare to discard hand call, thread 2
gdb/gdbserver/ChangeLog
2015-02-23 Pedro Alves <palves@redhat.com>
* linux-x86-low.c (REGSIZE): Define in both 32-bit and 64-bit
modes.
(x86_fill_gregset, x86_store_gregset): Use it when handling
$orig_eax.
TL;DR - GDB can hang if something refreshes the thread list out of the
target while the target is running. GDB hangs inside td_ta_thr_iter.
The fix is to not use that libthread_db function anymore.
Long version:
Running the testsuite against my all-stop-on-top-of-non-stop series is
still exposing latent non-stop bugs.
I was originally seeing this with the multi-create.exp test, back when
we were still using libthread_db thread event breakpoints. The
all-stop-on-top-of-non-stop series forces a thread list refresh each
time GDB needs to start stepping over a breakpoint (to pause all
threads). That test hits the thread event breakpoint often, resulting
in a bunch of step-over operations, thus a bunch of thread list
refreshes while some threads in the target are running.
The commit adds a real non-stop mode test that triggers the issue,
based on multi-create.exp, that does an explicit "info threads" when a
breakpoint is hit. IOW, it does the same things the as-ns series was
doing when testing multi-create.exp.
The bug is a race, so it unfortunately takes several runs for the test
to trigger it. In fact, even when setting the test running in a loop,
it sometimes takes several minutes for it to trigger for me.
The race is related to libthread_db's td_ta_thr_iter. This is
libthread_db's entry point for walking the thread list of the
inferior.
Sometimes, when GDB refreshes the thread list from the target,
libthread_db's td_ta_thr_iter can somehow see glibc's thread list as a
cycle, and get stuck in an infinite loop.
The issue is that when a thread exits, its thread control structure in
glibc is moved from a "used" list to a "cache" list. These lists are
simply circular linked lists where the "next/prev" pointers are
embedded in the thread control structure itself. The "next" pointer
of the last element of the list points back to the list's sentinel
"head". There's only one set of "next/prev" pointers for both lists;
thus a thread can only be in one of the lists at a time, not in both
simultaneously.
So when thread C exits, simplifying, the following happens. A-C are
threads. stack_used and stack_cache are the list's heads.
Before:
stack_used -> A -> B -> C -> (&stack_used)
stack_cache -> (&stack_cache)
After:
stack_used -> A -> B -> (&stack_used)
stack_cache -> C -> (&stack_cache)
td_ta_thr_iter starts by iterating at the list's head's next, and
iterates until it sees a thread whose next pointer points to the
list's head again. Thus in the before case above, C's next points to
stack_used, indicating end of list. In the same case, the stack_cache
list is empty.
For each thread being iterated, td_ta_thr_iter reads the whole thread
object out of the inferior. This includes the thread's "next"
pointer.
In the scenario above, it may happen that td_ta_thr_iter is iterating
thread B and has already read B's thread structure just before thread
C exits and its control structure moves to the cached list.
Now, recall that td_ta_thr_iter is running in the context of GDB, and
there's no locking between GDB and the inferior. From it's local copy
of B, td_ta_thr_iter believes that the next thread after B is thread
C, so it happilly continues iterating to C, a thread that has already
exited, and is now in the stack cache list.
After iterating C, td_ta_thr_iter finds the stack_cache head, which
because it is not stack_used, td_ta_thr_iter assumes it's just another
thread. After this, unless the reverse race triggers, GDB gets stuck
in td_ta_thr_iter forever walking the stack_cache list, as no thread
in thatlist has a next pointer that points back to stack_used (the
terminating condition).
Before fully understanding the issue, I tried adding cycle detection
to GDB's td_ta_thr_iter callback. However, td_ta_thr_iter skips
calling the callback in some cases, which means that it's possible
that the callback isn't called at all, making it impossible for GDB to
break the loop. I did manage to get GDB stuck in that state more than
once.
Fortunately, we can avoid the issue altogether. We don't really need
td_ta_thr_iter for live debugging nowadays, given PTRACE_EVENT_CLONE.
We already know how to map and lwp id to a thread id without iterating
(thread_from_lwp), so use that more.
gdb/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* linux-nat.c (linux_handle_extended_wait): Call
thread_db_notice_clone whenever a new clone LWP is detected.
(linux_stop_and_wait_all_lwps, linux_unstop_all_lwps): New
functions.
* linux-nat.h (thread_db_attach_lwp): Delete declaration.
(thread_db_notice_clone, linux_stop_and_wait_all_lwps)
(linux_unstop_all_lwps): Declare.
* linux-thread-db.c (struct thread_get_info_inout): Delete.
(thread_get_info_callback): Delete.
(thread_from_lwp): Use td_thr_get_info and record_thread.
(thread_db_attach_lwp): Delete.
(thread_db_notice_clone): New function.
(try_thread_db_load_1): If /proc is mounted and shows the
process'es task list, walk over all LWPs and call thread_from_lwp
instead of relying on td_ta_thr_iter.
(attach_thread): Don't call check_thread_signals here. Split the
tail part of the function (which adds the thread to the core GDB
thread list) to ...
(record_thread): ... this function. Call check_thread_signals
here.
(thread_db_wait): Don't call thread_db_find_new_threads_1. Always
call thread_from_lwp.
(thread_db_update_thread_list): Rename to ...
(thread_db_update_thread_list_org): ... this.
(thread_db_update_thread_list): New function.
(thread_db_find_thread_from_tid): Delete.
(thread_db_get_ada_task_ptid): Simplify.
* nat/linux-procfs.c: Include <sys/stat.h>.
(linux_proc_task_list_dir_exists): New function.
* nat/linux-procfs.h (linux_proc_task_list_dir_exists): Declare.
gdb/gdbserver/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* thread-db.c: Include "nat/linux-procfs.h".
(thread_db_init): Skip listing new threads if the kernel supports
PTRACE_EVENT_CLONE and /proc/PID/task/ is accessible.
gdb/testsuite/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* gdb.threads/multi-create-ns-info-thr.exp: New file.
Another fix I'm working made schedlock.exp fail with gdbserver
frequently. Looking deeper, it turns out to be a pre-existing bug.
status_pending_p_callback is filtering out LWPs incorrectly. The
result is that that sometimes status_pending_p_callback returns a
pending event for an LWP that isn't expected, and then GDBserver gets
very confused.
E.g,. when doing a step-over, linux_wait_for_event is called with a
particular LWP's ptid, meaning events for all other LWPs should be
left pending, but here we see it retuning an event for some other LWP:
linux_wait_1: [<all threads>]
step_over_bkpt set [LWP 29577.29577], doing a blocking wait <--------
my_waitpid (-1, 0x40000001)
my_waitpid (-1, 0x80000001): status(57f), 0
LWFE: waitpid(-1, ...) returned 0, ERRNO-OK
pc is 0x4007a0
src/gdb/gdbserver/linux-low.c:2587: A problem internal to GDBserver has been detected.
linux_wait_1: got event for 29581 <--------
Remote connection closed
(gdb) FAIL: gdb.threads/schedlock.exp: continue to breakpoint: return to loop (initial)
delete breakpoints
Tested on x86_64 Fedora 20.
gdb/gdbserver/ChangeLog:
2015-02-20 Pedro Alves <palves@redhat.com>
* linux-low.c (status_pending_p_callback): Use ptid_match.
When gdb creates a dummy frame to execute a function in the inferior,
the process may generate a SIGSEGV, SIGTRAP or SIGILL because the stack
is non executable. If the signal handler set in gdb has option print
or stop enabled for these signals gdb handles this correctly.
However, in the case of noprint and nostop the signal is short-circuited
and the inferior process is sent the signal directly. This causes the
inferior to crash because of gdb.
This patch adds a check for SIGSEGV, SIGTRAP or SIGILL so that these
signals are sent to gdb rather than short-circuited in the inferior.
gdb then handles them properly and the inferior process does not
crash.
This patch also fixes the same behavior in gdbserver.
Also added a small testcase to test the issue called catch-gdb-caused-signals.
This applies to Linux only, tested on Linux.
gdb/ChangeLog:
PR breakpoints/16812
* linux-nat.c (linux_nat_filter_event): Report SIGTRAP,SIGILL,SIGSEGV.
* nat/linux-ptrace.c (linux_wstatus_maybe_breakpoint): Add.
* nat/linux-ptrace.h: Add linux_wstatus_maybe_breakpoint.
gdb/gdbserver/ChangeLog:
PR breakpoints/16812
* linux-low.c (wstatus_maybe_breakpoint): Remove.
(linux_low_filter_event): Update wstatus_maybe_breakpoint name.
(linux_wait_1): Report SIGTRAP,SIGILL,SIGSEGV.
gdb/testsuite/ChangeLog:
PR breakpoints/16812
* gdb.base/catch-gdb-caused-signals.c: New file.
* gdb.base/catch-gdb-caused-signals.exp: New file.
When gdbserver is called with --multi and attach has not been called yet
and tstart is called on the gdb client, gdbserver would crash.
This patch fixes gdbserver so that it returns E01 to the gdb client.
Also this patch adds a testcase to verify this bug named no-attach-trace.exp
gdb/gdbserver/ChangeLog:
PR breakpoints/15956
* tracepoint.c (cmd_qtinit): Add check for current_thread.
gdb/testsuite/ChangeLog:
* gdb.trace/no-attach-trace.c: New file.
* gdb.trace/no-attach-trace.exp: New file.
Allow the size of the branch trace ring buffer to be defined by the
user. The specified buffer size will be used when BTS tracing is
enabled for new threads.
The obtained buffer size may differ from the requested size. The
actual buffer size for the current thread is shown in the "info record"
command.
Bigger buffers mean longer traces, but also longer processing time.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* btrace.c (parse_xml_btrace_conf_bts): Add size.
(btrace_conf_bts_attributes): New.
(btrace_conf_children): Add attributes.
* common/btrace-common.h (btrace_config_bts): New.
(btrace_config)<bts>: New.
(btrace_config): Update comment.
* nat/linux-btrace.c (linux_enable_btrace, linux_enable_bts):
Use config.
* features/btrace-conf.dtd: Increment version. Add size
attribute to bts element.
* record-btrace.c (set_record_btrace_bts_cmdlist,
show_record_btrace_bts_cmdlist): New.
(record_btrace_adjust_size, record_btrace_print_bts_conf,
record_btrace_print_conf, cmd_set_record_btrace_bts,
cmd_show_record_btrace_bts): New.
(record_btrace_info): Call record_btrace_print_conf.
(_initialize_record_btrace): Add commands.
* remote.c: Add PACKET_Qbtrace_conf_bts_size enum.
(remote_protocol_features): Add Qbtrace-conf:bts:size packet.
(btrace_sync_conf): Synchronize bts size.
(_initialize_remote): Add Qbtrace-conf:bts:size packet.
* NEWS: Announce new commands and new packets.
doc/
* gdb.texinfo (Branch Trace Configuration Format): Add size.
(Process Record and Replay): Describe new set|show commands.
(General Query Packets): Describe Qbtrace-conf:bts:size packet.
testsuite/
* gdb.btrace/buffer-size: New.
gdbserver/
* linux-low.c (linux_low_btrace_conf): Print size.
* server.c (handle_btrace_conf_general_set): New.
(hanle_general_set): Call handle_btrace_conf_general_set.
(handle_query): Report Qbtrace-conf:bts:size as supported.
Add a struct to describe the branch trace configuration and use it for
enabling branch tracing.
The user will be able to set configuration fields for each tracing format
to be used for new threads.
The actual configuration that is active for a given thread will be shown
in the "info record" command.
At the moment, the configuration struct only contains a format field
that is set to the only available format.
The format is the only configuration option that can not be set via set
commands. It is given as argument to the "record btrace" command when
starting recording.
2015-02-09 Markus Metzger <markus.t.metzger@intel.com>
* Makefile.in (XMLFILES): Add btrace-conf.dtd.
* x86-linux-nat.c (x86_linux_enable_btrace): Update parameters.
(x86_linux_btrace_conf): New.
(x86_linux_create_target): Initialize to_btrace_conf.
* nat/linux-btrace.c (linux_enable_btrace): Update parameters.
Check format. Split into this and ...
(linux_enable_bts): ... this.
(linux_btrace_conf): New.
(perf_event_skip_record): Renamed into ...
(perf_event_skip_bts_record): ... this. Updated users.
(linux_disable_btrace): Split into this and ...
(linux_disable_bts): ... this.
(linux_read_btrace): Check format.
* nat/linux-btrace.h (linux_enable_btrace): Update parameters.
(linux_btrace_conf): New.
(btrace_target_info)<ptid>: Moved.
(btrace_target_info)<conf>: New.
(btrace_target_info): Split into this and ...
(btrace_tinfo_bts): ... this. Updated users.
* btrace.c (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf_bts, parse_xml_btrace_conf)
(btrace_conf_children, btrace_conf_attributes)
(btrace_conf_elements): New.
* btrace.h (btrace_enable): Update parameters.
(btrace_conf, parse_xml_btrace_conf): New.
* common/btrace-common.h (btrace_config): New.
* feature/btrace-conf.dtd: New.
* record-btrace.c (record_btrace_conf): New.
(record_btrace_cmdlist): New.
(record_btrace_enable_warn, record_btrace_open): Pass
&record_btrace_conf.
(record_btrace_info): Print recording format.
(cmd_record_btrace_bts_start): New.
(cmd_record_btrace_start): Call cmd_record_btrace_bts_start.
(_initialize_record_btrace): Add "record btrace bts" subcommand.
Add "record bts" alias command.
* remote.c (remote_state)<btrace_config>: New.
(remote_btrace_reset, PACKET_qXfer_btrace_conf): New.
(remote_protocol_features): Add qXfer:btrace-conf:read.
(remote_open_1): Call remote_btrace_reset.
(remote_xfer_partial): Handle TARGET_OBJECT_BTRACE_CONF.
(btrace_target_info)<conf>: New.
(btrace_sync_conf, btrace_read_config): New.
(remote_enable_btrace): Update parameters. Call btrace_sync_conf and
btrace_read_conf.
(remote_btrace_conf): New.
(init_remote_ops): Initialize to_btrace_conf.
(_initialize_remote): Add qXfer:btrace-conf packet.
* target.c (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
* target.h (target_enable_btrace): Update parameters.
(target_btrace_conf): New.
(target_object)<TARGET_OBJECT_BTRACE_CONF>: New.
(target_ops)<to_enable_btrace>: Update parameters and comment.
(target_ops)<to_btrace_conf>: New.
* target-delegates: Regenerate.
* target-debug.h (target_debug_print_const_struct_btrace_config_p)
(target_debug_print_const_struct_btrace_target_info_p): New.
NEWS: Announce new command and new packet.
doc/
* gdb.texinfo (Process Record and Replay): Describe the "record
btrace bts" command.
(General Query Packets): Describe qXfer:btrace-conf:read packet.
(Branch Trace Configuration Format): New.
gdbserver/
* linux-low.c (linux_low_enable_btrace): Update parameters.
(linux_low_btrace_conf): New.
(linux_target_ops)<to_btrace_conf>: Initialize.
* server.c (current_btrace_conf): New.
(handle_btrace_enable): Rename to ...
(handle_btrace_enable_bts): ... this. Pass ¤t_btrace_conf
to target_enable_btrace. Update comment. Update users.
(handle_qxfer_btrace_conf): New.
(qxfer_packets): Add btrace-conf entry.
(handle_query): Report qXfer:btrace-conf:read as supported packet.
* target.h (target_ops)<enable_btrace>: Update parameters and comment.
(target_ops)<read_btrace_conf>: New.
(target_enable_btrace): Update parameters.
(target_read_btrace_conf): New.
testsuite/
* gdb.btrace/delta.exp: Update "info record" output.
* gdb.btrace/enable.exp: Update "info record" output.
* gdb.btrace/finish.exp: Update "info record" output.
* gdb.btrace/instruction_history.exp: Update "info record" output.
* gdb.btrace/next.exp: Update "info record" output.
* gdb.btrace/nexti.exp: Update "info record" output.
* gdb.btrace/step.exp: Update "info record" output.
* gdb.btrace/stepi.exp: Update "info record" output.
* gdb.btrace/nohist.exp: Update "info record" output.
