This patch adds support to remote targets for converting a thread
handle to a thread_info struct pointer.
A thread handle is fetched via a "handle" attribute which has been
added to the qXfer:threads:read query packet. An implementation is
provided in gdbserver for targets using the Linux kernel.
gdb/gdbserver/ChangeLog:
* linux-low.h (struct lwp_info): Add new field, thread_handle.
(thread_db_thread_handle): Declare.
* linux-low.c (linux_target_ops): Initialize thread_handle.
* server.c (handle_qxfer_threads_worker): Add support for
"handle" attribute.
* target.h (struct target_ops): Add new function pointer,
thread_handle.
(target_thread_handle): Define.
* thread-db.c (find_one_thread, attach_thread): Set thread_handle
field in lwp.
(thread_db_thread_handle): New function.
gdb/ChangeLog:
* remote.c (vector): Include.
(struct private_thread_info): Add field, thread_handle.
(free_private_thread_info): Deallocate storage associated with
thread handle.
(get_private_info_thread): Initialize `thread_handle' field.
(struct thread_item): Add field, thread_handle.
(clear_threads_listing_context): Deallocate storage associated
with thread handle.
(start_thread): Add support for "handle" attribute.
(thread_attributes): Add "handle".
(remote_get_threads_with_qthreadinfo): Initialize thread_handle
field.
(remote_update_thread_list): Update thread_handle.
(remote_thread_handle_to_thread_info): New function.
(init_remote_ops): Initialize to_thread_handle_to_thread_info.
While working on a patch for fetching a thread handle in gdbserver, I
ran into a circumstance in which tests in gdb.mi/mi-nsmoribund.exp
would occasionally fail. Over a large enough number of runs, it would
fail roughly 2% of the time.
That thread handle patch caused find_one_thread() to be called on
every stop. find_one_thread() calls td_ta_map_lwp2thr() which, in
turn, can cause ps_get_thread_area() to be called.
ps_get_thread_area() makes a call to ptrace() for getting the thread
area address. If this should happen when the thread is not stopped,
the call to ptrace will return error which in turn propogates back to
find_one_thread(). find_one_thread() calls error() in this instance
which causes the program to die.
This patch causes find_one_thread() to be called upon reciept of a
clone event. Since the clone is stopped, the circumstances described
above cannot occur.
gdb/gdbserver/ChangeLog:
* linux-low.c (handle_extended_wait): Call thread_db_notice_clone().
* linux-low.h (thread_db_notice_clone): Declare.
* thread-db.c (thread_db_notice_clone): New function.
This is a simple replacement, it allows removing some manual free'ing in
the callers.
gdb/ChangeLog:
* common/buffer.c (buffer_xml_printf): Adjust.
* common/xml-utils.c (xml_escape_text): Change return type to
std::string, update code accordingly.
* common/xml-utils.h (xml_escape_text): Change return type to
std::string.
* rs6000-aix-tdep.c (rs6000_aix_shared_library_to_xml): Adjust.
* windows-tdep.c (windows_xfer_shared_library): Adjust.
* unittests/xml-utils-selftests.c (test_xml_escape_text):
Adjust.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_qxfer_libraries_svr4): Adjust to change of
return type of xml_escape_text.
* server.c (emit_dll_description): Likewise.
This patch fixes the build breakage that has been happening on AArch64
since September 5th. The breakage was introduced by the following
commit:
author Yao Qi <yao.qi@linaro.org>
Tue, 5 Sep 2017 04:54:52 -0400 (09:54 +0100)
committer Yao Qi <yao.qi@linaro.org>
Tue, 5 Sep 2017 04:54:52 -0400 (09:54 +0100)
commit f7000548a2
Use VEC for target_desc.reg_defs
The build log for this commit can be seen here:
<https://gdb-build.sergiodj.net/builders/Ubuntu-AArch64-native-gdbserver-m64/builds/2696/steps/compile%20gdb/logs/stdio>
And the underlying problem is that the code is not calling the new
function "allocate_target_description" to allocate the "struct
target_desc" using "new" instead of XNEW, which end up not properly
initializing the fields of the structure.
Regtested on BuildBot.
gdb/gdbserver/ChangeLog:
2017-09-10 Sergio Durigan Junior <sergiodj@redhat.com>
* linux-low.c (handle_extended_wait): Use
"allocate_target_description" instead of "XNEW".
* linux-x86-low.c (initialize_low_arch): Likewise.
A quite straightforward change. It does "fix" leaks in record-btrace.c,
although since this is only used in debug printing code, it has no real
world impact.
gdb/ChangeLog:
* target/waitstatus.h (target_waitstatus_to_string): Change
return type to std::string.
* target/waitstatus.c (target_waitstatus_to_string): Return
std::string.
* target.h (target_waitstatus_to_string): Remove declaration.
* infrun.c (resume, clear_proceed_status_thread,
print_target_wait_results, do_target_wait, save_waitstatus,
stop_all_threads): Adjust.
* record-btrace.c (record_btrace_wait): Adjust.
* target-debug.h
(target_debug_print_struct_target_waitstatus_p): Adjust.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_wait_1): Adjust.
* server.c (queue_stop_reply_callback): Adjust.
I got confused by the result value of fast_tracepoint_collecting, while
it sounds like it would return true/false (whether the thread is
collecting or not), it actually returns:
0: not collecting
1: in the jump pad, before the relocated instruction
2: in the jump pad, at or after the relocated instruction
To avoid confusion, I think it would be nice to make it return an enum.
If you can help find a shorter but still relavant name, it would be
awesome. Otherwise, we'll go with that, fast_tpoint_collect_result,
which is at least consistent with the existing
fast_tpoint_collect_status.
gdb/gdbserver/ChangeLog:
* tracepoint.h (enum class fast_tpoint_collect_result): New
enumeration.
(fast_tracepoint_collecting): Change return type to
fast_tpoint_collect_result.
* tracepoint.c (fast_tracepoint_collecting): Likewise.
* linux-low.h: Include tracepoint.h.
(struct lwp_info) <collecting_fast_tracepoint>: Change type to
fast_tpoint_collect_result.
* linux-low.c (handle_tracepoints): Adjust.
(linux_fast_tracepoint_collecting): Change return type to
fast_tpoint_collect_result.
(maybe_move_out_of_jump_pad, linux_wait_for_event_filtered,
linux_wait_1, stuck_in_jump_pad_callback,
lwp_signal_can_be_delivered, linux_resume_one_lwp_throw,
proceed_one_lwp): Adjust to type change.
As part of the preparation necessary for my upcoming task, I'd like to
propose that we turn gdb_environ into a class. The approach taken
here is simple: the class gdb_environ contains everything that is
needed to manipulate the environment variables. These variables are
stored in an std::vector<char *>, which can be converted to a 'char
**' and passed as argument to functions that need it.
The usage has not changed much. As per Pedro's suggestion, this class
uses a static factory method initialization. This means that when an
instance is created, it is initially empty. When needed, it has to be
initialized using the static method 'from_host_environ'.
As mentioned before, this is a preparation for an upcoming work that I
will be posting in the next few weeks or so. For that work, I'll
probably create another data structure that will contain all the
environment variables that were set by the user using the 'set
environment' command, because I'll need access to them. This will be
much easier with the class-ification of gdb_environ.
As noted, this has been regression-tested with the new version of
environ.exp and no regressions were found.
gdb/ChangeLog:
2017-06-20 Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (SUBDIR_UNITTESTS_SRCS): Add
'unittests/environ-selftests.c'.
(SUBDIR_UNITTESTS_OBS): Add 'environ-selftests.o'.
* charset.c (find_charset_names): Declare object 'iconv_env'.
Update code to use 'iconv_env' object. Remove call to
'free_environ'.
* common/environ.c: Include <utility>.
(make_environ): Delete function.
(free_environ): Delete function.
(gdb_environ::clear): New function.
(gdb_environ::operator=): New function.
(gdb_environ::get): Likewise.
(environ_vector): Delete function.
(set_in_environ): Delete function.
(gdb_environ::set): New function.
(unset_in_environ): Delete function.
(gdb_environ::unset): New function.
(gdb_environ::envp): Likewise.
* common/environ.h: Include <vector>.
(struct gdb_environ): Delete; transform into...
(class gdb_environ): ... this class.
(free_environ): Delete prototype.
(init_environ, get_in_environ, set_in_environ, unset_in_environ,
environ_vector): Likewise.
* infcmd.c (run_command_1): Update code to call
'envp' from 'gdb_environ' class.
(environment_info): Update code to call methods from 'gdb_environ'
class.
(unset_environment_command): Likewise.
(path_info): Likewise.
(path_command): Likewise.
* inferior.c (inferior::~inferior): Delete call to 'free_environ'.
(inferior::inferior): Initialize 'environment' using the host's
information.
* inferior.h: Remove forward declaration of 'struct gdb_environ'.
Include "environ.h".
(class inferior) <environment>: Change type from 'struct
gdb_environ' to 'gdb_environ'.
* mi/mi-cmd-env.c (mi_cmd_env_path): Update code to call
methods from 'gdb_environ' class.
* solib.c (solib_find_1): Likewise
* unittests/environ-selftests.c: New file.
gdb/gdbserver/ChangeLog:
2017-06-20 Sergio Durigan Junior <sergiodj@redhat.com>
* linux-low.c (linux_create_inferior): Adjust code to access the
environment information via 'gdb_environ' class.
* lynx-low.c (lynx_create_inferior): Likewise.
* server.c (our_environ): Make it an instance of 'gdb_environ'.
(get_environ): Return a pointer to 'our_environ'.
(captured_main): Initialize 'our_environ'.
* server.h (get_environ): Adjust prototype.
* spu-low.c (spu_create_inferior): Adjust code to access the
environment information via 'gdb_environ' class.
AFAIK, the register keyword is not relevant today, and clang complains
about it:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-low.c:5873:3: error: 'register' storage class specifier is deprecated and incompatible with C++1z
[-Werror,-Wdeprecated-register]
register PTRACE_XFER_TYPE *buffer;
^~~~~~~~~
I think we can safely remove it.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_read_memory, linux_write_memory): Remove
usage of "register" keyword.
This is the most important (and the biggest, sorry) patch of the
series. It moves fork_inferior from gdb/fork-child.c to
nat/fork-inferior.c and makes all the necessary adjustments to both
GDB and gdbserver to make sure everything works OK.
There is no "most important change" with this patch; all changes are
made in a progressive way, making sure that gdbserver had the
necessary features while not breaking GDB at the same time.
I decided to go ahead and implement a partial support for starting the
inferior with a shell on gdbserver, although the full feature comes in
the next patch. The user won't have the option to disable the
startup-with-shell, and also won't be able to change which shell
gdbserver will use (other than setting the $SHELL environment
variable, that is).
Everything is working as expected, and no regressions were present
during the tests.
gdb/ChangeLog:
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* Makefile.in (HFILES_NO_SRCDIR): Add "common/common-inferior.h"
and "nat/fork-inferior.h".
* common/common-inferior.h: New file, with contents from
"gdb/inferior.h".
* commom/common-utils.c: Include "common-utils.h".
(stringify_argv): New function.
* common/common-utils.h (stringify_argv): New prototype.
* configure.nat: Add "fork-inferior.o" as a dependency for
"*linux*", "fbsd*" and "nbsd*" hosts.
* corefile.c (get_exec_file): Update comment.
* darwin-nat.c (darwin_ptrace_him): Call "gdb_startup_inferior"
instead of "startup_inferior".
(darwin_create_inferior): Call "add_thread_silent" after
"fork_inferior".
* fork-child.c: Cleanup unnecessary includes.
(SHELL_FILE): Move to "common/common-fork-child.c".
(environ): Likewise.
(exec_wrapper): Initialize.
(get_exec_wrapper): New function.
(breakup_args): Move to "common/common-fork-child.c"; rename to
"breakup_args_for_exec".
(escape_bang_in_quoted_argument): Move to
"common/common-fork-child.c".
(saved_ui): New variable.
(prefork_hook): New function.
(postfork_hook): Likewise.
(postfork_child_hook): Likewise.
(gdb_startup_inferior): Likewise.
(fork_inferior): Move to "common/common-fork-child.c". Update
function to support gdbserver.
(startup_inferior): Likewise.
* gdbcore.h (get_exec_file): Remove declaration.
* gnu-nat.c (gnu_create_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* inf-ptrace.c: Include "nat/fork-inferior.h" and "utils.h".
(inf_ptrace_create_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* inferior.h: Include "common-inferior.h".
(trace_start_error): Move to "common/common-utils.h".
(trace_start_error_with_name): Likewise.
(fork_inferior): Move prototype to "nat/fork-inferior.h".
(startup_inferior): Likewise.
(gdb_startup_inferior): New prototype.
* nat/fork-inferior.c: New file, with contents from "fork-child.c".
* nat/fork-inferior.h: New file.
* procfs.c (procfs_init_inferior): Call "gdb_startup_inferior"
instead of "startup_inferior". Call "add_thread_silent" after
"fork_inferior".
* target.h (target_terminal_init): Move prototype to
"target/target.h".
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* target/target.h (target_terminal_init): New prototype, moved
from "target.h".
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* utils.c (gdb_flush_out_err): New function.
gdb/gdbserver/ChangeLog:
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
Pedro Alves <palves@redhat.com>
* Makefile.in (SFILES): Add "nat/fork-inferior.o".
* configure: Regenerate.
* configure.srv (srv_linux_obj): Add "fork-child.o" and
"fork-inferior.o".
(i[34567]86-*-lynxos*): Likewise.
(spu*-*-*): Likewise.
* fork-child.c: New file.
* linux-low.c: Include "common-inferior.h", "nat/fork-inferior.h"
and "environ.h".
(linux_ptrace_fun): New function.
(linux_create_inferior): Adjust function prototype to reflect
change on "target.h". Adjust function code to use
"fork_inferior".
(linux_request_interrupt): Delete "signal_pid".
* lynx-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
(lynx_ptrace_fun): New function.
(lynx_create_inferior): Adjust function prototype to reflect
change on "target.h". Adjust function code to use
"fork_inferior".
* nto-low.c (nto_create_inferior): Adjust function prototype and
code to reflect change on "target.h". Update comments.
* server.c: Include "common-inferior.h", "nat/fork-inferior.h",
"common-terminal.h" and "environ.h".
(terminal_fd): Moved to fork-child.c.
(old_foreground_pgrp): Likewise.
(restore_old_foreground_pgrp): Likewise.
(last_status): Make it global.
(last_ptid): Likewise.
(our_environ): New variable.
(startup_with_shell): Likewise.
(program_name): Likewise.
(program_argv): Rename to...
(program_args): ...this.
(wrapper_argv): New variable.
(start_inferior): Delete function.
(get_exec_wrapper): New function.
(get_exec_file): Likewise.
(get_environ): Likewise.
(prefork_hook): Likewise.
(post_fork_inferior): Likewise.
(postfork_hook): Likewise.
(postfork_child_hook): Likewise.
(handle_v_run): Update code to deal with arguments coming from the
remote host. Update calls from "start_inferior" to
"create_inferior".
(captured_main): Likewise. Initialize environment variable. Call
"have_job_control".
* server.h (post_fork_inferior): New prototype.
(get_environ): Likewise.
(last_status): Declare.
(last_ptid): Likewise.
(signal_pid): Likewise.
* spu-low.c: Include "common-inferior.h" and "nat/fork-inferior.h".
(spu_ptrace_fun): New function.
(spu_create_inferior): Adjust function prototype to reflect change
on "target.h". Adjust function code to use "fork_inferior".
* target.c (target_terminal_init): New function.
(target_terminal_inferior): Likewise.
(target_terminal_ours): Likewise.
* target.h: Include <vector>.
(struct target_ops) <create_inferior>: Update prototype.
(create_inferior): Update macro.
* utils.c (gdb_flush_out_err): New function.
* win32-low.c (win32_create_inferior): Adjust function prototype
and code to reflect change on "target.h".
gdb/testsuite/ChangeLog:
2017-06-07 Sergio Durigan Junior <sergiodj@redhat.com>
* gdb.server/non-existing-program.exp: Update regex in order to
reflect the fact that gdbserver is now using fork_inferior (with a
shell) to startup the inferior.
This applies the second part of GDB's End of Year Procedure, which
updates the copyright year range in all of GDB's files.
gdb/ChangeLog:
Update copyright year range in all GDB files.
If the target can do software single step, it can do range
stepping.
gdb/gdbserver:
2016-10-27 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_supports_agent): Return true if
can_software_single_step return true.
Nowadays, we select events to be reported to GDB in random, however
that is not enough when many GDBserver internal events (not reported
to GDB) are generated.
GDBserver pulls all events out of kernel via waitpid, and leave them
pending. When goes through threads which have pending events,
GDBserver uses find_inferior to find the first thread which has
pending event, and consumes it. Note that find_inferior always
iterate threads in a fixed order. If multiple threads keep hitting
GDBserver breakpoints, range stepping with single-step breakpoint for
example, threads in the head of the thread list are more likely to be
processed and threads in the tail are starved. This causes some timeout
fails in gdb.threads/non-stop-fair-events.exp when range stepping is
enabled on arm-linux.
This patch fixes this issue by randomly selecting pending events. It
adds a new function find_inferior_in_random, which iterates threads
which have pending events randomly.
gdb/gdbserver:
2016-10-27 Yao Qi <yao.qi@linaro.org>
* inferiors.c (find_inferior_in_random): New function.
* inferiors.h (find_inferior_in_random): Declare.
* linux-low.c (linux_wait_for_event_filtered): Call
find_inferior_in_random instead of find_inferior.
This patch removes single-step breakpoints if the event is only
GDBserver internal, IOW, isn't reported back to GDB.
gdb/gdbserver:
2016-10-27 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_wait_1): If single-step breakpoints are
inserted, remove them.
Currently GDB never sends more than one action per vCont packet, when
connected in non-stop mode. A follow up patch will change that, and
it exposed a gdbserver problem with the vCont handling.
For example, this in non-stop mode:
=> vCont;s:p1.1;c
<= OK
Should be equivalent to:
=> vCont;s:p1.1
<= OK
=> vCont;c
<= OK
But gdbserver currently doesn't handle this. In the latter case,
"vCont;c" makes gdbserver clobber the previous step request. This
patch fixes that.
Note the server side must ignore resume actions for the thread that
has a pending %Stopped notification (and any other threads with events
pending), until GDB acks the notification with vStopped. Otherwise,
e.g., the following case is mishandled:
#1 => g (or any other packet)
#2 <= [registers]
#3 <= %Stopped T05 thread:p1.2
#4 => vCont s:p1.1;c
#5 <= OK
Above, the server must not resume thread p1.2 when it processes the
vCont. GDB can't know that p1.2 stopped until it acks the %Stopped
notification. (Otherwise it wouldn't send a default "c" action.)
(The vCont documentation already specifies this.)
Finally, special care must also be given to handling fork/vfork
events. A (v)fork event actually tells us that two processes stopped
-- the parent and the child. Until we follow the fork, we must not
resume the child. Therefore, if we have a pending fork follow, we
must not send a global wildcard resume action (vCont;c). We can still
send process-wide wildcards though.
(The comments above will be added as code comments to gdb in a follow
up patch.)
gdb/gdbserver/ChangeLog:
2016-10-26 Pedro Alves <palves@redhat.com>
* linux-low.c (handle_extended_wait): Link parent/child fork
threads.
(linux_wait_1): Unlink them.
(linux_set_resume_request): Ignore resume requests for
already-resumed and unhandled fork child threads.
* linux-low.h (struct lwp_info) <fork_relative>: New field.
* server.c (in_queued_stop_replies_ptid, in_queued_stop_replies):
New functions.
(handle_v_requests) <vCont>: Don't call require_running.
* server.h (in_queued_stop_replies): New declaration.
When I read the GDBserver debug message, I find the "entering" of
linux_wait_1 doesn't match the "existing" of linux_wait_1. Looks
we don't call debug_exit somewhere in linux_wait_1 on return.
gdb/gdbserver:
2016-09-26 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_wait_1): Call debug_exit.
Add the function lwp_is_stepping which indicates whether the given LWP
is currently single-stepping. This is a common interface, usable from
native GDB as well as from gdbserver.
gdb/gdbserver/ChangeLog:
* linux-low.c (lwp_is_stepping): New function.
gdb/ChangeLog:
* nat/linux-nat.h (lwp_is_stepping): New declaration.
* linux-nat.c (lwp_is_stepping): New function.
reinsert_breakpoint is used for software single step, so it is more
clear to rename it to single_step_breakpoint. This was pointed out in
the review https://sourceware.org/ml/gdb-patches/2016-05/msg00429.html
I don't rename "other_breakpoint" in this patch.
gdb/gdbserver:
2016-09-02 Yao Qi <yao.qi@linaro.org>
* linux-low.c: Replace "reinsert_breakpoints" with
"single_step_breakpoints". Replace "reinsert breakpoints"
with "single-step breakpoints".
* mem-break.c: Likewise.
* mem-break.h: Likewise.
This patch fixes imbalanced lwp_suspend/unsuspend calls caused by the
premature choosing of another event for fairness.
select_event_lwp would switch the event before a call to
unsuspend_all_lwps, thus it would be called with the wrong event.
This caused an assertion failure: unsuspend LWP xx, suspended=-1 when
testing gdb.threads/non-stop-fair-events.exp with ARM range stepping in
GDBServer.
This patch moves the switch of event after the unsuspend/unstop calls.
No regressions, tested on ubuntu 14.04 ARMv7 and x86.
With gdbserver-native.
gdb/gdbserver/ChangeLog:
* linux-low.c (linux_wait_1): Move event switch after unsuspend_lwps.
gdb's (or gdbserver's) own signal handling should not interfere with
the signal dispositions their spawned children inherit. However, it
currently does. For example, some paths in gdb cause SIGPIPE to be
set to SIG_IGN, and as consequence, the child starts with SIGPIPE to
set to SIG_IGN too, even though gdb was started with SIGPIPE set to
SIG_DFL.
This is because the exec family of functions does not reset the signal
disposition of signals that are set to SIG_IGN:
http://pubs.opengroup.org/onlinepubs/7908799/xsh/execve.html
Signals set to the default action (SIG_DFL) in the calling process
image are set to the default action in the new process
image. Signals set to be ignored (SIG_IGN) by the calling process
image are set to be ignored by the new process image. Signals set to
be caught by the calling process image are set to the default action
in the new process image (see <signal.h>).
And neither does it reset signal masks or flags.
In order to be transparent, when spawning new child processes to debug
(with "run", etc.), reset signal actions and mask back to what was
originally inherited from gdb/gdbserver's parent, just before execing
the target program to debug.
gdb/ChangeLog:
2016-08-09 Pedro Alves <palves@redhat.com>
PR gdb/18653
* Makefile.in (SFILES): Add
common/signals-state-save-restore.c.
(HFILES_NO_SRCDIR): Add common/signals-state-save-restore.h.
(COMMON_OBS): Add signals-state-save-restore.o.
(signals-state-save-restore.o): New rule.
* configure: Regenerate.
* fork-child.c: Include "signals-state-save-restore.h".
(fork_inferior): Call restore_original_signals_state.
* main.c: Include "signals-state-save-restore.h".
(captured_main): Call save_original_signals_state.
* common/common.m4: Add sigaction to AC_CHECK_FUNCS checks.
* common/signals-state-save-restore.c: New file.
* common/signals-state-save-restore.h: New file.
gdb/gdbserver/ChangeLog:
2016-08-09 Pedro Alves <palves@redhat.com>
PR gdb/18653
* Makefile.in (OBS): Add signals-state-save-restore.o.
(signals-state-save-restore.o): New rule.
* config.in: Regenerate.
* configure: Regenerate.
* linux-low.c: Include "signals-state-save-restore.h".
(linux_create_inferior): Call
restore_original_signals_state.
* server.c: Include "dispositions-save-restore.h".
(captured_main): Call save_original_signals_state.
gdb/testsuite/ChangeLog:
2016-08-09 Pedro Alves <palves@redhat.com>
PR gdb/18653
* gdb.base/signals-state-child.c: New file.
* gdb.base/signals-state-child.exp: New file.
* gdb.gdb/selftest.exp (do_steps_and_nexts): Add new pattern.
When I run process-dies-while-detaching.exp with GDBserver, I see many
warnings printed by GDBserver,
ptrace(regsets_fetch_inferior_registers) PID=26183: No such process
ptrace(regsets_fetch_inferior_registers) PID=26183: No such process
ptrace(regsets_fetch_inferior_registers) PID=26184: No such process
ptrace(regsets_fetch_inferior_registers) PID=26184: No such process
regsets_fetch_inferior_registers is called when GDBserver resumes each
lwp.
#2 0x0000000000428260 in regsets_fetch_inferior_registers (regsets_info=0x4690d0 <aarch64_regsets_info>, regcache=0x31832020)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:5412
#3 0x00000000004070e8 in get_thread_regcache (thread=0x31832940, fetch=fetch@entry=1) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/regcache.c:58
#4 0x0000000000429c40 in linux_resume_one_lwp_throw (info=<optimized out>, signal=0, step=0, lwp=0x31832830)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4463
#5 linux_resume_one_lwp (lwp=0x31832830, step=<optimized out>, signal=<optimized out>, info=<optimized out>)
at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4573
The is the case that threads are disappeared when GDB/GDBserver resumes
them. We check errno for ESRCH, and don't print error messages, like
what we are doing in regsets_store_inferior_registers.
gdb/gdbserver:
2016-08-04 Yao Qi <yao.qi@linaro.org>
* linux-low.c (regsets_fetch_inferior_registers): Check
errno is ESRCH or not.
This patch is to teach GDBserver using software single step to handle
vCont;s. Simply speaking, if the thread's resume request is resume_step,
install reinsert breakpoint at the next pcs when GDBserver is about to
resume threads. These reinsert breakpoints of a thread are removed,
when GDBserver gets an event from that thread and reports it back to
GDB.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* linux-low.c (resume_stopped_resumed_lwps): If resume request
is resume_step, call maybe_hw_step.
(linux_wait_1): Stop all threads, remove reinsert breakpoints,
and unstop them.
(linux_resume_one_lwp_throw): Don't assert the thread has reinsert
breakpoints or not.
(proceed_one_lwp): If resume request is resume_step, install
reinsert breakpoints and call maybe_hw_step.
Nowadays, we only enqueue signal when we leave thread pending in
linux_resume_one_thread. If lwp->resume->sig isn't zero (GDB wants
to resume with signal), we pass lwp->resume->sig to
linux_resume_one_lwp.
In order to reduce the difference between resuming thread with signal
and proceeding thread with signal, when we resume thread, we can
enqueue signal too, and proceed thread. The signal will be consumed in
linux_resume_one_lwp_throw from lwp->pending_signals.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* linux-low.c (proceed_one_lwp): Declare.
(linux_resume_one_thread): Remove local variable 'step'.
Lift code enqueue signal. Call proceed_one_lwp instead of
linux_resume_one_lwp.
install_software_single_step_breakpoints has parameter lwp, but still
need to switch to current_thread. In order to simplify its caller,
we do the current_thread save/restore inside install_software_single_step_breakpoints.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* gdbthread.h (make_cleanup_restore_current_thread): Declare.
* inferiors.c (do_restore_current_thread_cleanup): New function.
(make_cleanup_restore_current_thread): Likewise.
* linux-low.c (install_software_single_step_breakpoints): Call
make_cleanup_restore_current_thread. Switch current_thread to
thread.
This patch makes reinsert_breakpoint thread specific, which means we
insert and remove reinsert_breakpoint breakpoints for a specific
thread. This motivation of this change is that I'll use
reinsert_breakpoint for vCont;s on software single step target, so that
GDBserver may insert one reinsert_breakpoint for one thread doing
step-over, and insert one reinsert_breakpoint for another thread doing
vCont;s. After the operation of one thread is finished, GDBserver must
remove reinsert_breakpoint for that thread only.
On the other hand, reinsert_breakpoint is used for step-over nowadays.
GDBserver inserts reinsert_breakpoint, and wait only from the thread
doing step-over. After the step-over is done, GDBserver removes the
reinsert_breakpoint. If there is still any threads need step-over, do
the same again until all threads are finished step-over. In other words,
reinsert_breakpoint is globally thread specific, but in an implicit way.
It is natural to make it explicitly thread specific.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* mem-break.c (struct reinsert_breakpoint) <ptid>: New field.
(set_reinsert_breakpoint): New parameter ptid. Callers updated.
(clone_one_breakpoint): Likewise.
(delete_reinsert_breakpoints): Change parameter to thread.
Callers updated.
(has_reinsert_breakpoints): Likewise.
(uninsert_reinsert_breakpoints): Likewise.
(reinsert_reinsert_breakpoints): Likewise.
* mem-break.h (set_reinsert_breakpoint): Update declaration.
(delete_reinsert_breakpoints): Likewise.
(reinsert_reinsert_breakpoints): Likewise.
(uninsert_reinsert_breakpoints): Likewise.
(has_reinsert_breakpoints): Likewise.
This patch is to change the interface of clone_all_breakpoints, from
lists of breakpoints and raw_breakpoints to child thread and parent
thread. I choose child thread to pass because we need the ptid of
the child thread in the following patch.
gdb/gdbserver:
2016-07-21 Yao Qi <yao.qi@linaro.org>
* inferiors.c (get_thread_process): Make parameter const.
* inferiors.h (get_thread_process): Update declaration.
* mem-break.c (clone_all_breakpoints): Remove all parameters.
Add new parameters child_thread and parent_thread. Callers
updated.
* mem-break.h (clone_all_breakpoints): Update declaration.
This commit fixes detaching on Linux when some thread exits the whole
thread group (process) just while we're detaching.
On Linux, a ptracer must detach from each LWP individually, with
PTRACE_DETACH. Since PTRACE_DETACH sets the thread running free, if
one of the already-detached threads causes the whole thread group to
exit (e.g., simply calls exit), the kernel force-kills the other
threads in the group, making them zombie, just as we're still
detaching them. Since PTRACE_DETACH against a zombie thread fails
with ESRCH, and gdb/gdbserver are not expecting this, the detach fails
with an error like: "Can't detach process: No such process.".
This patch detects this detach failure as normal, and instead of
erroring out, reaps the now-dead thread.
New test included, that exercises several different scenarios that
cause GDB/GDBserver to error out when it should not.
Tested on x86-64 GNU/Linux with {unix, native-gdbserver,
native-extended-gdbserver}
Note: without the previous fix, the "single-process + continue"
variant of the new test would fail with:
(gdb) PASS: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: switch to parent
continue
Continuing.
Warning:
Could not insert hardware watchpoint 3.
Could not insert hardware breakpoints:
You may have requested too many hardware breakpoints/watchpoints.
Command aborted.
(gdb) FAIL: gdb.threads/process-dies-while-detaching.exp: single-process: continue: watchpoint: continue
gdb/gdbserver/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* linux-low.c: Change interface to take the target lwp_info
pointer directly and return void. Handle detaching from a zombie
thread.
(linux_detach_lwp_callback): New function.
(linux_detach): Detach from the leader thread after detaching from
the clone threads.
gdb/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* inf-ptrace.c (inf_ptrace_detach_success): New function, factored
out from ...
(inf_ptrace_detach): ... here.
* inf-ptrace.h (inf_ptrace_detach_success): New declaration.
* linux-nat.c (get_pending_status): Rename to ...
(get_detach_signal): ... this, and return a host signal instead of
filling in a wait status.
(detach_one_lwp): New function, factored out from detach_callback
and adjusted to handle detaching from a zombie thread.
(detach_callback): Skip the leader thread.
(linux_nat_detach): No longer defer to inf_ptrace_detach to detach
the leader thread, nor build a signal string to pass down.
Instead, use target_announce_detach, detach_one_lwp and
inf_ptrace_detach_success.
gdb/testsuite/ChangeLog:
2016-07-01 Pedro Alves <palves@redhat.com>
Antoine Tremblay <antoine.tremblay@ericsson.com>
* gdb.threads/process-dies-while-detaching.c: New file.
* gdb.threads/process-dies-while-detaching.exp: New file.
When I implement linux_target_ops.get_syscall_trapinfo for aarch64 and arm,
I find the second parameter sysret isn't used at all. In RSP, we don't
need syscall return value either, because GDB can figure out the return
value from registers content got by 'g' packet.
This patch is to remove them.
gdb/gdbserver:
2016-06-28 Yao Qi <yao.qi@linaro.org>
* linux-low.c (get_syscall_trapinfo): Remove parameter sysret.
Callers updated.
* linux-low.h (struct linux_target_ops) <get_syscall_trapinfo>:
Remove parameter sysno.
* linux-x86-low.c (x86_get_syscall_trapinfo): Remove parameter
sysret.
When a thread is doing step-over with reinsert breakpoint, and the
instruction executed is a syscall doing vfork, both parent and child
share the memory, so the reinsert breakpoint in the space is visible
to both of them. Also, removing the reinsert breakpoints from the
child will effectively remove them from the parent. We should
carefully manipulate reinsert breakpoints for both processes.
What we are doing here is that
- uninsert reinsert breakpoints from the parent before cloning the
breakpoint list. We use "uninsert" instead of "remove", because
we need to "reinsert" them back after vfork is done. In fact,
"uninsert" removes them from both child and parent process space.
- reinsert breakpoints in parent process are still copied to child's
breakpoint list,
- remove them from child's breakpoint list as what we did for fork,
at this point, reinsert breakpoints are removed from the child and
the parent, but they are still tracked by the parent's breakpoint
list,
- once vfork is done, "reinsert" them back to the parent,
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (handle_extended_wait): Call
uninsert_reinsert_breakpoints for the parent process. Remove
reinsert breakpoints from the child process. Reinsert them to
the parent process when vfork is done.
* mem-break.c (uninsert_reinsert_breakpoints): New function.
(reinsert_reinsert_breakpoints): New function.
* mem-break.h (uninsert_reinsert_breakpoints): Declare
(reinsert_reinsert_breakpoints): Declare.
When a thread is stepping over a syscall instruction with software
single step, GDBserver inserts reinsert breakpoints at the next pcs.
If the syscall call is fork, the forked child has reinsert breakpoint
in its space, and GDBserver clones parent's breakpoint list to child's.
When GDBserver resumes the child, its bp_reinsert is zero, but has
reinsert breakpoints, so the following assert is triggered if I apply
the patch extending step-over-syscall.exp.
gdb/gdbserver/linux-low.c:4292: A problem internal to GDBserver has been detected.^M
void linux_resume_one_lwp_throw(lwp_info*, int, int, siginfo_t*): Assertion `!has_reinsert_breakpoints (proc)' failed.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (handle_extended_wait): If the parent is doing
step-over, remove the reinsert breakpoints from the forked child.
This patch fixes a GDBserver crash when one thread is stepping over
a syscall instruction which is exit. Step-over isn't finished due
to the exit, but GDBserver doesn't clean up the state of step-over,
so in the wait next time, GDBserver will wait on step_over_bkpt,
which is already exited, and GDBserver crashes because
'requested_child' is NULL. See gdbserver logs below,
Need step over [LWP 14858]? yes, found breakpoint at 0x2aaaaad91307^M
proceed_all_lwps: found thread 14858 needing a step-over^M
Starting step-over on LWP 14858. Stopping all threads^M
>>>> entering void stop_all_lwps(int, lwp_info*)
....
<<<< exiting void stop_all_lwps(int, lwp_info*)^M
Done stopping all threads for step-over.^M
pc is 0x2aaaaad91307^M
Writing 0f to 0x2aaaaad91307 in process 14858^M
Could not find fast tracepoint jump at 0x2aaaaad91307 in list (uninserting).^M
pending reinsert at 0x2aaaaad91307^M
step from pc 0x2aaaaad91307^M
Resuming lwp 14858 (step, signal 0, stop not expected)^M
# Start step-over for LWP 14858
>>>> entering ptid_t linux_wait_1(ptid_t, target_waitstatus*, int)
....
LLFE: 14858 exited.
...
<<<< exiting ptid_t linux_wait_1(ptid_t, target_waitstatus*, int)
# LWP 14858 exited
.....
>>>> entering ptid_t linux_wait_1(ptid_t, target_waitstatus*, int)^M
linux_wait_1: [<all threads>]^M
step_over_bkpt set [LWP 14858.14858], doing a blocking wait
# but step_over_bkpt is still LWP 14858, which is wrong
The fix is to finish step-over if it is ongoing, and unsuspend other
threads. Without the fix in linux-low.c, GDBserver will crash in
with running gdb.base/step-over-exit.exp.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (unsuspend_all_lwps): Declare.
(linux_low_filter_event): If thread exited, call finish_step_over.
If step-over is finished, unsuspend other threads.
gdb/testsuite:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* gdb.base/step-over-exit.c: New.
* gdb.base/step-over-exit.exp: New.
This patch adds more asserts, so the incorrect or sub-optimal
reinsert breakpoints manipulations (from the tests in the following
patches) can trigger them.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_resume_one_lwp_throw): Assert
has_reinsert_breakpoints returns false.
* mem-break.c (delete_disabled_breakpoints): Assert
bp type isn't reinsert_breakpoint.
This patch adds some sanity check that reinsert breakpoints must be
there when doing step-over on software single step target. The check
triggers an assert when running forking-threads-plus-breakpoint.exp
on arm-linux target,
gdb/gdbserver/linux-low.c:4714: A problem internal to GDBserver has been detected.^M
int finish_step_over(lwp_info*): Assertion `has_reinsert_breakpoints ()' failed.
the error happens when GDBserver has already resumed a thread of
process A for step-over (and wait for it hitting reinsert breakpoint),
but receives detach request for process B from GDB, which is shown in
the backtrace below,
(gdb) bt
#2 0x000228aa in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4703
#3 0x00025a50 in finish_step_over (lwp=0x12bbd98) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4749
#4 complete_ongoing_step_over () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:4760
#5 linux_detach (pid=25228) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/linux-low.c:1503
#6 0x00012bae in process_serial_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3974
#7 handle_serial_event (err=<optimized out>, client_data=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:4347
#8 0x00016d68 in handle_file_event (event_file_desc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:429
#9 0x000173ea in process_event () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:184
#10 start_event_loop () at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/event-loop.c:547
#11 0x0000aa2c in captured_main (argv=<optimized out>, argc=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3719
#12 main (argc=<optimized out>, argv=<optimized out>) at /home/yao/SourceCode/gnu/gdb/git/gdb/gdbserver/server.c:3804
the sanity check tries to find the reinsert breakpoint from process B,
but nothing is found. It is wrong, we need to search in process A,
since we started step-over of a thread of process A.
(gdb) p lwp->thread->entry.id
$3 = {pid = 25120, lwp = 25131, tid = 0}
(gdb) p current_thread->entry.id
$4 = {pid = 25228, lwp = 25228, tid = 0}
This patch switched current_thread to the thread we are doing step-over
in finish_step_over.
gdb/gdbserver:
2016-06-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (maybe_hw_step): New function.
(linux_resume_one_lwp_throw): Call maybe_hw_step.
(finish_step_over): Switch current_thread to lwp temporarily,
and assert has_reinsert_breakpoints returns true.
(proceed_one_lwp): Call maybe_hw_step.
* mem-break.c (has_reinsert_breakpoints): New function.
* mem-break.h (has_reinsert_breakpoints): Declare.
This patch is to replace find_inferior (&all_threads, unsuspend_one_lwp, NULL)
with unsuspend_all_lwps (NULL), which is shorter. They are equivalent
to each other.
gdb/gdbserver:
2016-05-17 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_stabilize_threads): Call unsuspend_all_lwps
instead of find_inferior.
Hi,
I happen to see that field need_step_over in struct lwp_info is only
used to print a debug info. need_step_over is set in linux_wait_1
when breakpoint_here is true, however, we check breakpoint_here too in
need_step_over_p and do the step over. I think we don't need field
need_step_over, and check breakpoint_here directly in need_step_over_p.
This field was added in this patch
https://sourceware.org/ml/gdb-patches/2010-03/msg00605.html and the code
wasn't changed much since then.
This patch is to remove it.
gdb/gdbserver:
2016-04-28 Yao Qi <yao.qi@linaro.org>
* linux-low.h (struct lwp_info) <need_step_over>: Remove.
* linux-low.c (linux_wait_1): Update.
(need_step_over_p): Likewise.
When GDBserver steps over a breakpoint using software single step, it
enqueues the signal, single step and deliver the signal in the next
resume if step over is not needed. In this way, the program won't
receive the signal if the conditional breakpoint is set a branch to
self instruction, because the step over is always needed.
This patch removes the restriction that don't deliver the signal to
the inferior if we are trying to reinsert a breakpoint for software
single step and change the decision on resume vs. step-over when the
LWP has pending signals to deliver.
gdb/gdbserver:
2016-04-25 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): Adjust.
(need_step_over_p): Return zero if the LWP has pending signals
can be delivered on software single step target.
GDBserver doesn't deliver signal when stepping over a breakpoint even
hardware single step is used. When GDBserver started to step over
(thread creation) breakpoint for mutlit-threaded debugging in 2002 [1],
GDBserver behaves this way.
This behavior gets trouble on conditional breakpoints on branch to
self instruction like this,
0x00000000004005b6 <+29>: jmp 0x4005b6 <main+29>
and I set breakpoint
$(gdb) break branch-to-self.c:43 if counter > 3
and the variable counter will be set to 5 in SIGALRM signal handler.
Since GDBserver keeps stepping over breakpoint, the SIGALRM can never
be dequeued and delivered to the inferior, so the program can't stop.
The test can be found in gdb.base/branch-to-self.exp.
GDBserver didn't deliver signal when stepping over a breakpoint because
a tracepoint is collected twice if GDBserver does so in the following
scenario, which can be reproduced by gdb.trace/signal.exp.
- program stops at tracepoint, and tracepoint is collected,
- gdbserver starts a step-over,
- a signal arrives, step-over is canceled, and signal should be passed,
- gdbserver starts a new step-over again, pass the signal as well,
- program stops at the entry of signal handler, step-over finished,
- gdbserver proceeds,
- program returns from the signal handler, again to the tracepoint,
and thus is collected again.
The spurious collection isn't that harmful, IMO, so it should be OK
to let GDBserver deliver signal when stepping over a breakpoint.
gdb/gdbserver:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): Don't deliver
signal when stepping over breakpoint with software single
step.
gdb/testsuite:
2016-04-22 Yao Qi <yao.qi@linaro.org>
* gdb.trace/signal.exp: Also pass if
$tracepoint_hits($i) > $iterations.
The enqueue and dequeue signals in linux_resume_one_lwp_throw use one
condition and its inverted one. This patch is to move the condition
into a function lwp_signal_can_be_delivered, so that the next patch can
change the condition in one place.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (lwp_signal_can_be_delivered): New function.
(linux_resume_one_lwp_throw): Use lwp_signal_can_be_delivered.
Today, we enqueue signal in linux_resume_one_lwp_throw, but set
variable 'signal' many lines below with the comment
/* Postpone any pending signal. It was enqueued above. */
signal = 0;
I feel difficult to associate code across many lines, and we should
move the code close to enqueue_pending_signal call. This is what
this patch does in general. After this change, variable 'signal'
is set to zero very early, so the 'signal' value in the following
debugging message makes no sense, so I remove it from the debugging
message. The function returns early if lwp->status_pending_p is
true, so 'signal' value in the debugging message doesn't matter,
AFAICS. Also, I move one debugging message several lines below to
make it close the real ptrace call,
if (debug_threads)
debug_printf ("Resuming lwp %ld (%s, signal %d, stop %s)\n",
lwpid_of (thread), step ? "step" : "continue", signal,
lwp->stop_expected ? "expected" : "not expected");
so that the debugging message can reflect what GDBserver does. This
is a code refactor and only debugging messages are affected.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_resume_one_lwp_throw): Set 'signal' to
0 if signal is enqueued. Remove 'signal' from one debugging
message. Move one debugging message to some lines below.
Remove code setting 'signal' to 0.
WIFSTOPPED is checked linux_wstatus_maybe_breakpoint, so WIFSTOPPED
in "WIFSTOPPED (wstat) && linux_wstatus_maybe_breakpoint (wstat)"
is redundant. This patch removes WIFSTOPPED check.
gdb/gdbserver:
2016-03-18 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_low_filter_event): Remove redundant
WIFSTOPPED check together with linux_wstatus_maybe_breakpoint.
I happen to see that comments to start_step_over isn't in sync with
code, so this patch is to update the comments.
gdb/gdbserver:
2016-03-03 Yao Qi <yao.qi@linaro.org>
* linux-low.c: Update comments to start_step_over.
I see the following GDBserver internal error in two cases,
gdb/gdbserver/linux-low.c:1922: A problem internal to GDBserver has been detected.
unsuspend LWP 17200, suspended=-1
1. step over a breakpoint on fork/vfork syscall instruction,
2. step over a breakpoint on clone syscall instruction and child
threads hits a breakpoint,
the stack backtrace is
#0 internal_error (file=file@entry=0x44c4c0 "gdb/gdbserver/linux-low.c", line=line@entry=1922,
fmt=fmt@entry=0x44c7d0 "unsuspend LWP %ld, suspended=%d\n") at gdb/gdbserver/../common/errors.c:51
#1 0x0000000000424014 in lwp_suspended_decr (lwp=<optimised out>, lwp=<optimised out>) at gdb/gdbserver/linux-low.c:1922
#2 0x000000000042403a in unsuspend_one_lwp (entry=<optimised out>, except=0x66e8c0) at gdb/gdbserver/linux-low.c:2885
#3 0x0000000000405f45 in find_inferior (list=<optimised out>, func=func@entry=0x424020 <unsuspend_one_lwp>, arg=arg@entry=0x66e8c0)
at gdb/gdbserver/inferiors.c:243
#4 0x00000000004297de in unsuspend_all_lwps (except=0x66e8c0) at gdb/gdbserver/linux-low.c:2895
#5 linux_wait_1 (ptid=..., ourstatus=ourstatus@entry=0x665ec0 <last_status>, target_options=target_options@entry=0)
at gdb/gdbserver/linux-low.c:3632
#6 0x000000000042a764 in linux_wait (ptid=..., ourstatus=0x665ec0 <last_status>, target_options=0)
at gdb/gdbserver/linux-low.c:3770
#7 0x0000000000411163 in mywait (ptid=..., ourstatus=ourstatus@entry=0x665ec0 <last_status>, options=options@entry=0, connected_wait=connected_wait@entry=1)
at gdb/gdbserver/target.c:214
#8 0x000000000040b1f2 in resume (actions=0x66f800, num_actions=1) at gdb/gdbserver/server.c:2757
#9 0x000000000040f660 in handle_v_cont (own_buf=0x66a630 "vCont;c:p45e9.-1") at gdb/gdbserver/server.c:2719
when GDBserver steps over a thread, other threads have been suspended,
the "stepping" thread may create new thread, but GDBserver doesn't set
it suspend count to 1. When GDBserver unsuspend threads, the child's
suspend count goes to -1, and the assert is triggered. In fact, GDBserver
has already taken care of suspend count of new thread when GDBserver is
suspending all threads except the one GDBserver wants to step over by
https://sourceware.org/ml/gdb-patches/2015-07/msg00946.html
+ /* If we're suspending all threads, leave this one suspended
+ too. */
+ if (stopping_threads == STOPPING_AND_SUSPENDING_THREADS)
+ {
+ if (debug_threads)
+ debug_printf ("HEW: leaving child suspended\n");
+ child_lwp->suspended = 1;
+ }
but that is not enough, because new thread is still can be spawned in
the thread which is being stepped over. This patch extends the
condition that GDBserver set child's suspend count to one if it is
suspending threads or stepping over the thread.
gdb/gdbserver:
2016-03-03 Yao Qi <yao.qi@linaro.org>
PR server/19736
* linux-low.c (handle_extended_wait): Set child suspended
if event_lwp->bp_reinsert isn't zero.
Replace the code which is exactly what enqueue_pending_signal does.
gdb/gdbserver:
2016-03-02 Yao Qi <yao.qi@linaro.org>
* linux-low.c (linux_resume_one_lwp_throw): Replace code with
enqueue_pending_signal.
If gdbserver and IPA are using different tdesc, they will disagree
about 'R' trace packet size. This results in mangled traces.
To make sure they pick the same tdesc, gdbserver pokes the tdesc
(specified as an index in a target-specific list) into a global
variable in IPA. In theory, IPA could find out the tdesc on its
own, but that may be complex (in particular, I don't know how to
tell whether we have LAST_BREAK on s390 without messing with ptrace),
and we'd have to duplicate the logic.
Tested on i386 and x86_64. On i386, it fixes two FAILs in ftrace.exp.
On x86_64, these failures have been KFAILed - one of them works now,
but the other now fails due to an unrelated reason (ugh).
gdb/gdbserver/ChangeLog:
PR gdb/13808
* Makefile.in: Add i386-*-linux-ipa.o and amd64-*-linux-ipa.o.
* configure.srv: Ditto.
* linux-aarch64-ipa.c (get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment.
* linux-amd64-ipa.c: Add "linux-x86-tdesc.h" include.
(init_registers_amd64_linux): Remove prototype.
(tdesc_amd64_linux): Remove declaration.
(get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment,
initialize remaining tdescs.
* linux-i386-ipa.c: Add "linux-x86-tdesc.h" include.
(init_registers_i386_linux): Remove prototype.
(tdesc_i386_linux): Remove declaration.
(get_ipa_tdesc): New function.
(initialize_low_tracepoint): Remove ipa_tdesc assignment,
initialize remaining tdescs.
* linux-low.c (linux_get_ipa_tdesc_idx): New function.
(linux_target_ops): wire in linux_get_ipa_tdesc_idx.
* linux-low.h (struct linux_target_ops): Add get_ipa_tdesc_idx.
* linux-x86-low.c: Move tdesc declarations to linux-x86-tdesc.h.
(x86_get_ipa_tdesc_idx): New function.
(the_low_target): Wire in x86_get_ipa_tdesc_idx.
* linux-x86-tdesc.h: New file.
* target.h (struct target_ops): Add get_ipa_tdesc_idx.
(target_get_ipa_tdesc_idx): New macro.
* tracepoint.c (ipa_tdesc_idx): New macro.
(struct ipa_sym_addresses): Add addr_ipa_tdesc_idx.
(symbol_list): Add ipa_tdesc_idx.
(cmd_qtstart): Write ipa_tdesc_idx in the target.
(ipa_tdesc): Remove.
(ipa_tdesc_idx): New variable.
(get_context_regcache): Use get_ipa_tdesc.
(gdb_collect): Ditto.
(gdb_probe): Ditto.
* tracepoint.h (get_ipa_tdesc): New prototype.
(ipa_tdesc): Remove.
gdb/testsuite/ChangeLog:
PR gdb/13808
* gdb.trace/ftrace.exp (test_fast_tracepoints): Remove kfail.
This unbreaks pending/delayed breakpoints handling, as well as
hardware watchpoints, on MIPS.
Ref: https://sourceware.org/ml/gdb-patches/2016-02/msg00681.html
The MIPS kernel reports SI_KERNEL for all kernel generated traps,
instead of TRAP_BRKPT / TRAP_HWBKPT, but GDB isn't aware of this.
Basically, this commit:
- Folds watchpoints logic into check_stopped_by_breakpoint, and
renames it to save_stop_reason.
- Adds GDB_ARCH_IS_TRAP_HWBKPT.
- Makes MIPS set both GDB_ARCH_IS_TRAP_BRPT and
GDB_ARCH_IS_TRAP_HWBKPT to SI_KERNEL. In save_stop_reason, we
handle the case of the same si_code returning true for both
TRAP_BRPT and TRAP_HWBKPT by looking at what the debug registers
say.
Tested on x86-64 Fedora 20, native and gdbserver.
gdb/ChangeLog:
2016-02-24 Pedro Alves <palves@redhat.com>
* linux-nat.c (save_sigtrap) Delete.
(stop_wait_callback): Call save_stop_reason instead of
save_sigtrap.
(check_stopped_by_breakpoint): Rename to ...
(save_stop_reason): ... this. Bits of save_sigtrap folded here.
Use GDB_ARCH_IS_TRAP_HWBKPT and handle ambiguous
GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT. Factor out
common code between the USE_SIGTRAP_SIGINFO and
!USE_SIGTRAP_SIGINFO blocks.
(linux_nat_filter_event): Call save_stop_reason instead of
save_sigtrap.
* nat/linux-ptrace.h: Check for both SI_KERNEL and TRAP_BRKPT
si_code for MIPS.
* nat/linux-ptrace.h: Fix "TRAP_HWBPT" typo in x86 table. Add
comments on MIPS behavior.
(GDB_ARCH_IS_TRAP_HWBKPT): Define for all archs.
gdb/gdbserver/ChangeLog:
2016-02-24 Pedro Alves <palves@redhat.com>
* linux-low.c (check_stopped_by_breakpoint): Rename to ...
(save_stop_reason): ... this. Use GDB_ARCH_IS_TRAP_HWBKPT and
handle ambiguous GDB_ARCH_IS_TRAP_BRKPT / GDB_ARCH_IS_TRAP_HWBKPT.
Factor out common code between the USE_SIGTRAP_SIGINFO and
!USE_SIGTRAP_SIGINFO blocks.
(linux_low_filter_event): Call save_stop_reason instead of
check_stopped_by_breakpoint and check_stopped_by_watchpoint.
Update comments.
(linux_wait_1): Update comments.
Change the signature of gdbserver's siginfo_fixup functions so that it's
in line with gdb's. This gets rid of the following build error in C++:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c: In function ‘int x86_siginfo_fixup(siginfo_t*, void*, int)’:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:694:21: error: invalid conversion from ‘void*’ to ‘gdb_byte* {aka unsigned char*}’ [-fpermissive]
FIXUP_32);
^
In file included from /home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:31:0:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/../nat/amd64-linux-siginfo.h:52:5: error: initializing argument 2 of ‘int amd64_linux_siginfo_fixup_common(siginfo_t*, gdb_byte*, int, amd64_siginfo_fixup_mode)’ [-fpermissive]
int amd64_linux_siginfo_fixup_common (siginfo_t *native, gdb_byte *inf,
^
/home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:698:20: error: invalid conversion from ‘void*’ to ‘gdb_byte* {aka unsigned char*}’ [-fpermissive]
FIXUP_X32);
^
In file included from /home/emaisin/src/binutils-gdb/gdb/gdbserver/linux-x86-low.c:31:0:
/home/emaisin/src/binutils-gdb/gdb/gdbserver/../nat/amd64-linux-siginfo.h:52:5: error: initializing argument 2 of ‘int amd64_linux_siginfo_fixup_common(siginfo_t*, gdb_byte*, int, amd64_siginfo_fixup_mode)’ [-fpermissive]
int amd64_linux_siginfo_fixup_common (siginfo_t *native, gdb_byte *inf,
^
gdb/gdbserver/ChangeLog:
* linux-aarch64-low.c (aarch64_linux_siginfo_fixup): Change
void * to gdb_byte *.
* linux-low.c (siginfo_fixup): Likewise.
(linux_xfer_siginfo): Likewise.
* linux-low.h (struct linux_target_ops) <siginfo_fixup>:
Likewise.
* linux-x86-low.c (x86_siginfo_fixup): Likewise.
