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Spotted that we'd gained two 'New commands' sections in our 'Changes
since GDB 14' NEWS file block. I've merged them together.
Also, one of these two sections was actually called 'New Commands',
however, all the other places in the NEWS file use 'New commands', so
I've changed to use that.
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According to we have changed all E_MIPS_* to EF_MIPS_* in binutils
and glibc, we also need to change it here to keep same style.
We can refer to this commit record:
https://sourceware.org/pipermail/binutils/2023-October/129904.html
Approved-By: Pedro Alves <pedro@palves.net>
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Simon noticed that gdb.threads/threads-after-exec.exp was racy. You
can consistenly reproduce it (at git hash
319b460545dc79280e2904dcc280057cf71fb753), with:
$ taskset -c 0 make check TESTS="gdb.threads/threads-after-exec.exp"
gdb.log shows:
(...)
Thread 3 "threads-after-e" hit Catchpoint 2 (exec'd .../gdb.threads/threads-after-exec/threads-after-exec), 0x00007ffff7fe3290
in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) PASS: gdb.threads/threads-after-exec.exp: continue until exec
info threads
Id Target Id Frame
* 3 process 1443269 "threads-after-e" 0x00007ffff7fe3290 in _start () from /lib64/ld-linux-x86-64.so.2
(gdb) FAIL: gdb.threads/threads-after-exec.exp: info threads
(...)
maint info linux-lwps
LWP Ptid Thread ID
1443269.1443269.0 1.3
(gdb) FAIL: gdb.threads/threads-after-exec.exp: maint info linux-lwps
The FAILs happen because the .exp file expects that after the exec,
the only thread has GDB thread number 1, but it has instead 3.
This is yet another case of zombie leader detection making things a
bit fuzzy.
In the passing case, we have:
continue
Continuing.
[New Thread 0x7ffff7bff640 (LWP 603183)]
[Thread 0x7ffff7bff640 (LWP 603183) exited]
process 603180 is executing new program: .../gdb.threads/threads-after-exec/threads-after-exec
While in the failing case, we have (note remarks on the rhs):
continue
Continuing.
[New Thread 0x7ffff7bff640 (LWP 600205)]
[Thread 0x7ffff7f95740 (LWP 600202) exited] <<< gdb deletes leader thread, thread 1.
[New LWP 600202] <<< gdb adds it back -- this is now thread 3.
[Thread 0x7ffff7bff640 (LWP 600205) exited]
process 600202 is executing new program: .../threads-after-exec/threads-after-exec
The testcase only has two threads, yet GDB presented the exec for
thread 3. This is GDB deleting the leader (the backend detected it
was zombie, due to the exec), and then adding the leader back when it
saw the exec event.
I've recorded some thoughts about this in PR gdb/31069.
For now, this commit just makes the testcase cope with the non-one
thread number, as the number is not important for what this test is
exercising.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31069
Change-Id: Id80b5c73f09c9e0005efeb494cca5d066ac3bbae
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If you run gdb in the build tree without --data-directory, on a
program that does not have debug info, it will crash, because
gdbpy_handle_missing_debuginfo unconditionally uses gdb_python_module.
Other code in gdb using gdb_python_module checks it first and it
seemes harmless to do the same thing here. (gdb_python_initialized
does not cover this case so that python can be partially initialized
and still somewhat work.)
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This changes ada-nested.exp to fix a test name (the test expects three
variables but is named "two"), and to iterate over all the variables
that are found. It also adds a workaround to a problem Tom de Vries
found with an older version of GNAT -- it emits a duplicate "x".
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Doing this on behalf of Arsen as obvious. Hopefully the last fixup.
* gdb: Regenerate.
* gnulib: Regenerate.
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Doing this on behalf of Arsen as obvious.
* gdb: Regenerate.
* gdbserver: Regenerate.
* gprofng: Regenerate.
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* intl: Remove directory. Replaced with out-of-tree GNU gettext.
* .gitignore: Add '/gettext*'.
* configure.ac (host_libs): Replace intl with gettext. (hbaseargs, bbaseargs, baseargs): Split baseargs into {h,b}baseargs. (skip_barg): New flag. Skips appending current flag to bbaseargs. <library exemptions>: Exempt --with-libintl-{type,prefix} from target and build machine argument passing.
* configure: Regenerate.
* Makefile.def (host_modules): Replace intl module with gettext module. (configure-ld): Depend on configure-gettext.
* Makefile.in: Regenerate.
* src-release.sh: Remove references to the intl/ directory.
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'runtest' complains about a path in a test name, from the new test
case py-missing-debug.exp.
This patch fixes the problem by providing an explicit test name to
gdb_test. I chose something very basic because the block in question
is already wrapped in with_test_prefix.
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I found some "break" statements that follow "return" or a call to a
noreturn function. These aren't needed, and the compiler would warn
if they were. So, this patch removes them.
Tested by rebuilding.
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Kévin found a bug in an earlier version of this series that was based
on a misconception I had about Symbol.is_variable. This patch fixes
the documentation to explain the method a bit better.
Approved-By: Eli Zaretskii <eliz@gnu.org>
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A co-worker requested that the DAP scope for a nested function's frame
also show the variables from outer frames. DAP doesn't directly
support this notion, so this patch arranges to put these variables
into the inner frames "Locals" scope.
I chose to do this only for DAP. For CLI and MI, gdb currently does
not do this, so this preserves the behavior.
Note that an earlier patch (see commit 4a1311ba) removed some code
that seemed to do something similar. However, that code did not
actually work.
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While working on static links, I noticed that the DAP scopes code does
not handle the scenario where a frame decorator returns None. This
situation should be handled identically to a frame decorator returning
an empty iterator.
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This adds a new gdb.Frame.static_link method to the gdb Python layer.
This can be used to find the static link frame for a given frame.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
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This moves the follow_static_link function to frame.c and exports it
for use elsewhere. The API is changed slightly to make it more
generically useful.
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This adds the method block::function_block, to easily access a block's
enclosing function block.
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This adds a couple of convenience methods, block::is_static_block and
block::is_global_block.
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Change-Id: I67d8361560ce0fa553b2983184c9d18df8dbeb4a
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Change-Id: I211d64393f5c0da3c9ce1fcf5486504d34ed38f4
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Change-Id: Ic9164fd19c3da1381302a17176e8f0f814e9ac6c
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Replace some spaces with tabs.
Change-Id: I89bbabd6610219649e7e99cd0dd7b0ed66d69b09
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I noticed that tui_locator_window has an empty do_scroll_vertical and
do_scroll_horizontal, like tui_cmd_window, but unlike tui_cmd_window doesn't
have:
...
bool can_scroll () const override
{
return false;
}
...
I suspect that it probably doesn't matter, but regardless it's good to have
the same implementations of basic properties in all windows.
Ensure this by adding a class tui_noscroll_window, that has:
- an empty do_scroll_vertical and do_scroll_horizontal, and
- a can_scroll returning false
which both tui_locator_window and tui_cmd_window inherit.
Make all methods final to ensure no accidental overrides are left in the
inheriting classes.
Likewise add new classes representing basic window properties:
- tui_nofocus_window,
- tui_oneline_window,
- tui_nobox_window,
- tui_norefresh_window, and
- tui_always_visible_window.
The changes are only a refactoring, apart from adding the "final", which does
limit the range of behaviours for subclasses.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
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Refactor the ARGTYPES regular expression in make-target-delegates.py
to eliminate '.*' for better control on what is matched. Also,
simplify the "E" match group, for which the optional SYMBOL becomes
redundant because that case can be matched by the "T" group.
After applying this patch, running './make-target-delegates.py' does not
change anything in 'target-delegates.c'.
Approved-By: Pedro Alves <pedro@palves.net>
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I ran './make-target-delegates.py' and there is one minor difference,
where an older style declaration is converted to a newer
initialization style. Add this change.
Approved-By: Pedro Alves <pedro@palves.net>
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I ran into the following FAIL:
...
(gdb) PASS: gdb.threads/stepi-over-clone.exp: catch process syscalls
continue^M
Continuing.^M
^M
Catchpoint 2 (call to syscall clone), clone () at \
../sysdeps/unix/sysv/linux/x86_64/clone.S:78^M
warning: 78 ../sysdeps/unix/sysv/linux/x86_64/clone.S: \
No such file or directory^M
(gdb) FAIL: gdb.threads/stepi-over-clone.exp: continue
...
All but one regexps in the .exp file use "clone\[23\]?" with "?" to
also accept "clone", except the failing case. This commit fixes that
case to also use "?".
Furthermore, there are FAILs like this:
...
(gdb) PASS: gdb.threads/stepi-over-clone.exp: third_thread=false: \
non-stop=on: displaced=off: i=0: continue
stepi^M
[New Thread 0x7ffff7ff8700 (LWP 15301)]^M
Hello from the first thread.^M
78 in ../sysdeps/unix/sysv/linux/x86_64/clone.S^M
(gdb) XXX: Consume the initial command
XXX: Consume new thread line
XXX: Consume first worker thread message
FAIL: gdb.threads/stepi-over-clone.exp: third_thread=false: non-stop=on: \
displaced=off: i=0: stepi
...
because this output is expected instead:
...
Hello from the first thread.^M
0x00000000004212cd in clone3 ()^M
...
The root cause for the difference is the presence of .debug_line info for
clone.
Fix this by updating the relevant regexps.
Tested on x86_64-linux, specifically:
- openSUSE Leap 15.4 (where the FAILs where observed), and
- openSUSE Tumbleweed (where the FAILs where not observed).
Co-Authored-By: Pedro Alves <pedro@palves.net>
Approved-By: Pedro Alves <pedro@palves.net>
Change-Id: I74ca9e7d4cfe6af294fd50e8c509fcbad289b78c
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This commit builds on the previous commit, and implements the
extension_language_ops::handle_missing_debuginfo function for Python.
This hook will give user supplied Python code a chance to help find
missing debug information.
The implementation of the new hook is pretty minimal within GDB's C++
code; most of the work is out-sourced to a Python implementation which
is modelled heavily on how GDB's Python frame unwinders are
implemented.
The following new commands are added as commands implemented in
Python, this is similar to how the Python unwinder commands are
implemented:
info missing-debug-handlers
enable missing-debug-handler LOCUS HANDLER
disable missing-debug-handler LOCUS HANDLER
To make use of this extension hook a user will create missing debug
information handler objects, and registers these handlers with GDB.
When GDB encounters an objfile that is missing debug information, each
handler is called in turn until one is able to help. Here is a
minimal handler that does nothing useful:
import gdb
import gdb.missing_debug
class MyFirstHandler(gdb.missing_debug.MissingDebugHandler):
def __init__(self):
super().__init__("my_first_handler")
def __call__(self, objfile):
# This handler does nothing useful.
return None
gdb.missing_debug.register_handler(None, MyFirstHandler())
Returning None from the __call__ method tells GDB that this handler
was unable to find the missing debug information, and GDB should ask
any other registered handlers.
By extending the __call__ method it is possible for the Python
extension to locate the debug information for objfile and return a
value that tells GDB how to use the information that has been located.
Possible return values from a handler:
- None: This means the handler couldn't help. GDB will call other
registered handlers to see if they can help instead.
- False: The handler has done all it can, but the debug information
for the objfile still couldn't be found. GDB will not call
any other handlers, and will continue without the debug
information for objfile.
- True: The handler has installed the debug information into a
location where GDB would normally expect to find it. GDB
should look again for the debug information.
- A string: The handler can return a filename, which is the file
containing the missing debug information. GDB will load
this file.
When a handler returns True, GDB will look again for the debug
information, but only using the standard built-in build-id and
.gnu_debuglink based lookup strategies. It is not possible for an
extension to trigger another debuginfod lookup; the assumption is that
the debuginfod server is remote, and out of the control of extensions
running within GDB.
Handlers can be registered globally, or per program space. GDB checks
the handlers for the current program space first, and then all of the
global handles. The first handler that returns a value that is not
None, has "handled" the objfile, at which point GDB continues.
Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Tom Tromey <tom@tromey.com>
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This commit adds a new extension_language_ops hook which allows an
extension to handle the case where GDB can't find a separate debug
information file for a particular objfile.
This commit doesn't actually implement the hook for any of GDB's
extension languages, the next commit will do that. This commit just
adds support for the hook to extension-priv.h and extension.[ch], and
then reworks symfile-debug.c to call the hook.
Right now the hook will always return its default value, which means
GDB should do nothing different. As such, there should be no user
visible changes after this commit.
I'll give a brief description of what the hook does here so that we
can understand the changes in symfile-debug.c. The next commit adds a
Python implementation for this new hook, and gives a fuller
description of the new functionality.
Currently, when looking for separate debug information GDB tries three
things, in this order:
1. Use the build-id to find the required debug information,
2. Check for .gnu_debuglink section and use that to look up the
required debug information,
3. Check with debuginfod to see if it can supply the required
information.
The new extension_language_ops::handle_missing_debuginfo hook is
called if all three steps fail to find any debug information. The
hook has three possible return values:
a. Nothing, no debug information is found, GDB continues without the
debug information for this objfile. This matches the current
behaviour of GDB, and is the default if nothing is implementing this
new hook,
b. Install debug information into a location that step #1 or #2
above would normally check, and then request that GDB repeats steps
#1 and #2 in the hope that GDB will now find the debug information.
If the debug information is still not found then GDB carries on
without the debug information. If the debug information is found
the GDB loads it and carries on,
c. Return a filename for a file containing the required debug
information. GDB loads the contents of this file and carries on.
The changes in this commit mostly involve placing the core of
objfile::find_and_add_separate_symbol_file into a loop which allows
for steps #1 and #2 to be repeated.
We take care to ensure that debuginfod is only queried once, the first
time through. The assumption is that no extension is going to be able
to control the replies from debuginfod, so there's no point making a
second request -- and as these requests go over the network, they
could potentially be slow.
The warnings that find_and_add_separate_symbol_file collects are
displayed only once assuming that no debug information is found. If
debug information is found, even after the extension has operated,
then the warnings are not shown; remember, these are warnings from GDB
about failure to find any suitable debug information, so it makes
sense to hide these if debug information is found.
Approved-By: Tom Tromey <tom@tromey.com>
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This is purely a refactoring commit.
This commit splits objfile::find_and_add_separate_symbol_file into
some separate helper functions. My hope is that the steps for looking
up separate debug information are now clearer.
In a later commit I'm going to extend
objfile::find_and_add_separate_symbol_file, with some additional
logic, so starting with a simpler function will make the following
changes easier.
When reading objfile::find_and_add_separate_symbol_file after this
commit, you might be tempted to think that removing the `has_dwarf`
local variable would be a good additional cleanup. After the next
commit though it makes more sense to retain this local, so I've left
this in place for now.
There should be no user visible changes after this commit.
Approved-By: Tom Tromey <tom@tromey.com>
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This commit merges the code that looks for and loads the separate
debug symbol files from coffread.c and elfread.c. The factored out
code is moved into a new objfile::find_and_add_separate_symbol_file()
method.
For the elfread.c path there should be no user visible changes after
this commit.
For the coffread.c path GDB will now attempt to perform a debuginfod
lookup for the missing debug information, assuming that GDB can find a
build-id in the COFF file.
I don't know if COFF files can include a build-id, but I the existing
coffread.c code already includes a call to
find_separate_debug_file_by_build-id, so I know that it is at least OK
for GDB to ask a COFF file for a build-id. If the COFF file doesn't
include a build-id then the debuginfod lookup code will not trigger
and the new code is harmless.
If the COFF file does include a build-id, then we're going to end up
asking debuginfod for the debug file. As build-ids should be unique,
this should be harmless, even if debuginfod doesn't contain any
suitable debug data, it just costs us one debuginfod lookup, so I'm
not too worried about this for now.
As with the previous commit, I've done some minimal testing using the
mingw toolchain on a Linux machine, GDB seems to still access the
split debug information just fine.
Approved-By: Tom Tromey <tom@tromey.com>
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In this commit:
commit 8a92335bfca80cc9b4cd217505ea0dcbfdefbf07
Date: Fri Feb 1 19:39:04 2013 +0000
the logic for when we try to load a separate debug file in elfread.c
was extended. The new code checks that the objfile doesn't already
have a separate debug objfile linked to it, and that the objfile isn't
itself a separate debug objfile for some other objfile.
The coffread code wasn't extended at the same time.
I don't know if it's possible for the coffread code to get into the
same state where these checks are needed, but I don't see why having
these checks would be a problem. In a later commit I plan to merge
this part of the elfread and coffread code, so bringing these two
pieces of code into line first makes that job easier.
I've tested this with a simple test binary compiled with the mingw
toolchain on a Linux host. After compiling the binary and splitting
out the debug info GDB still finds and loads the separate debug info.
Approved-By: Tom Tromey <tom@tromey.com>
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Currently left_margin does not match its documentation:
...
/* Return the size of the left margin space, this is the space used to
display things like breakpoint markers. */
int left_margin () const
{ return box_width () + TUI_EXECINFO_SIZE + extra_margin (); }
...
It is stated that the left margin is reserved to display things, but
the box_width is not used for that.
Fix this by dropping box_width () from the left_margin calculation.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
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In tui_source_window::set_contents we have:
...
/* Take hilite (window border) into account, when
calculating the number of lines. */
int nlines = height - 2;
...
The '2' represents the total size of the window border (or box, in can_box
terms), in this case one line at the top and one line at the bottom.
Likewise, '1' is used to represent the width of the window border.
Introduce new functions:
- tui_win_info::box_width () and
- tui_win_info::box_size ()
that can be used instead instead of these hardcoded constants.
Implement these such that they return 0 when can_box () == false.
Tested patch completeness by making all windows unboxed:
...
@@ -85,7 +85,7 @@ struct tui_win_info
/* Return true if this window can be boxed. */
virtual bool can_box () const
{
- return true;
+ return false;
}
int box_width () const
...
and test-driving TUI.
This required eliminating an assert in
tui_source_window_base::show_source_content, I've included that part as well.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
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Currently the call to prefresh in tui_source_window_base::refresh_window looks
like:
...
prefresh (m_pad.get (), 0, pad_x, y + 1, x + left_margin,
y + m_content.size (), x + left_margin + view_width - 1);
...
This is hard to parse. It's not obvious what the arguments mean, and there's
repetition in the argument calculation.
Fix this by rewriting the call as follows:
- use sminrow, smincol, smaxrow and smaxcol variables for the last
4 arguments, and
- calculate the smaxrow and smaxcol variables based on the sminrow and
smincol variables.
Tested on x86_64-linux.
Approved-By: Tom Tromey <tom@tromey.com>
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The original intention of the test appears to be checking to make sure
setting a breakpoint in an inlined function didn't set multiple
breakpoints where one of them was at address 0.
The gdb.ada/inline-section-gc.exp test may pass or fail depending on the
version of gnat. Per the discussion on IRC, the ada inlining appears to
have some target dependencies. In this test there are two functions,
callee and caller. Function calee is inlined into caller. The test sets
a breakpoint in function callee. The reported location where the
breakpoint is set may be at the requested location in callee or the
location in caller after callee has been inlined. The test needs to
accept either location as correct provided the breakpoint address is not
zero.
This patch checks to see if the reported breakpoint is in function callee
or function caller and fails if the breakpoint address is 0x0. The line
number where the breakpoint is set will match the requested line if the
breakpoint location is reported is callee.adb. If the breakpoint is
reported in caller.adb, the line number in caller is the breakpoint
location in callee where it is inlined into caller.
This patch fixes the single regression failure for the test on PowerPC.
It does not introduce any failures on X86-64.
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If your target has no support for TARGET_WAITKIND_NO_RESUMED events
(and no way to support them, such as the yet-unsubmitted AMDGPU
target), and you step over thread exit with scheduler-locking on, this
is what you get:
(gdb) n
[Thread ... exited]
*hang*
Getting back the prompt by typing Ctrl-C may not even work, since no
inferior thread is running to receive the SIGINT. Even if it works,
it seems unnecessarily harsh. If you started an execution command for
which there's a clear thread of interest (step, next, until, etc.),
and that thread disappears, then I think it's more user friendly if
GDB just detects the situation and aborts the command, giving back the
prompt.
That is what this commit implements. It does this by explicitly
requesting the target to report thread exit events whenever the main
resumed thread has a thread_fsm. Note that unlike stepping over a
breakpoint, we don't need to enable clone events in this case.
With this patch, we get:
(gdb) n
[Thread 0x7ffff7d89700 (LWP 3961883) exited]
Command aborted, thread exited.
(gdb)
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I901ab64c91d10830590b2dac217b5264635a2b95
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This commit documents in both manual and NEWS:
- the new remote clone event stop reply,
- the new QThreadOptions packet and its current defined options,
- the associated "set/show remote thread-events-packet" command,
- and the associated QThreadOptions qSupported feature.
Approved-By: Eli Zaretskii <eliz@gnu.org>
Change-Id: Ic1c8de1fefba95729bbd242969284265de42427e
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Add new gdb.threads/step-over-thread-exit.exp and
gdb.threads/step-over-thread-exit-while-stop-all-threads.exp
testcases, exercising stepping over thread exit syscall. These make
use of lib/my-syscalls.S to define the exit syscall.
Co-authored-by: Pedro Alves <pedro@palves.net>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
Change-Id: Ie8b2c5747db99b7023463a897a8390d9e814a9c9
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Refactor the syscall assembly code in gdb/testsuite/lib/my-syscalls.S
behind a SYSCALL macro so that it's easy to add new syscalls without
duplicating code.
Note that the way the macro is implemented, it only works correctly
for syscalls with up to 3 arguments, and, if the syscall doesn't
return (the macro doesn't bother to save/restore callee-saved
registers).
The following patch will want to use the macro to define a wrapper for
the "exit" syscall, so the limitations continue to be sufficient.
Change-Id: I8acf1463b11a084d6b4579aaffb49b5d0dea3bba
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
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If scheduler-locking is in effect, e.g., with "set scheduler-locking
on", and you step over a function that spawns a new thread, the new
thread is allowed to run free, at least until some event is hit, at
which point, whether the new thread is re-resumed depends on a number
of seemingly random factors. E.g., if the target is all-stop, and the
parent thread hits a breakpoint, and GDB decides the breakpoint isn't
interesting to report to the user, then the parent thread is resumed,
but the new thread is left stopped.
I think that letting the new threads run with scheduler-locking
enabled is a defect. This commit fixes that, making use of the new
clone events on Linux, and of target_thread_events() on targets where
new threads have no connection to the thread that spawned them.
Testcase and documentation changes included.
Approved-By: Eli Zaretskii <eliz@gnu.org>
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie12140138b37534b7fc1d904da34f0f174aa11ce
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Running the
gdb.threads/step-over-thread-exit-while-stop-all-threads.exp testcase
added later in the series against gdbserver, after the
TARGET_WAITKIND_NO_RESUMED fix from the following patch, would run
into an infinite loop in stop_all_threads, leading to a timeout:
FAIL: gdb.threads/step-over-thread-exit-while-stop-all-threads.exp: displaced-stepping=off: target-non-stop=on: iter 0: continue (timeout)
The is really a latent bug, and it is about the fact that
stop_all_threads stops listening to events from a target as soon as it
sees a TARGET_WAITKIND_NO_RESUMED, ignoring that
TARGET_WAITKIND_NO_RESUMED may be delayed. handle_no_resumed knows
how to handle delayed no-resumed events, but stop_all_threads was
never taught to.
In more detail, here's what happens with that testcase:
#1 - Multiple threads report breakpoint hits to gdb.
#2 - gdb picks one events, and it's for thread 1. All other stops are
left pending. thread 1 needs to move past a breakpoint, so gdb
stops all threads to start an inline step over for thread 1.
While stopping threads, some of the threads that were still
running report events that are also left pending.
#2 - gdb steps thread 1
#3 - Thread 1 exits while stepping (it steps over an exit syscall),
gdbserver reports thread exit for thread 1
#4 - Thread 1 was the last resumed thread, so gdbserver also reports
no-resumed:
[remote] Notification received: Stop:w0;p3445d0.3445d3
[remote] Sending packet: $vStopped#55
[remote] Packet received: N
[remote] Sending packet: $vStopped#55
[remote] Packet received: OK
#5 - gdb processes the thread exit for thread 1, finishes the step
over and restarts threads.
#6 - gdb picks the next event to process out of one of the resumed
threads with pending events:
[infrun] random_resumed_with_pending_wait_status: Found 32 events, selecting #11
#7 - This is again a breakpoint hit and the breakpoint needs to be
stepped over too, so gdb starts a step-over dance again.
#8 - We reach stop_all_threads, which finds that some threads need to
be stopped.
#9 - wait_one finally consumes the no-resumed event queue by #4.
Seeing this, wait_one disable target async, to stop listening for
events out of the remote target.
#10 - We still haven't seen all the stops expected, so
stop_all_threads tries another iteration.
#11 - Because the remote target is no longer async, and there are no
other targets, wait_one return no-resumed immediately without
polling the remote target.
#12 - We still haven't seen all the stops expected, so
stop_all_threads tries another iteration. goto #11, looping
forever.
Fix this by explicitly enabling/re-enabling target async on targets
that can async, before waiting for stops.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie3ffb0df89635585a6631aa842689cecc989e33f
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GDB doesn't handle correctly the case where a thread steps over a
breakpoint (using either in-line or displaced stepping), and the
executed instruction causes the thread to exit.
Using the test program included later in the series, this is what it
looks like with displaced-stepping, on x86-64 Linux, where we have two
displaced-step buffers:
$ ./gdb -q -nx --data-directory=data-directory build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit -ex "b my_exit_syscall" -ex r
Reading symbols from build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit...
Breakpoint 1 at 0x123c: file src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S, line 68.
Starting program: build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/../lib/libthread_db.so.1".
[New Thread 0x7ffff7c5f640 (LWP 2915510)]
[Switching to Thread 0x7ffff7c5f640 (LWP 2915510)]
Thread 2 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
68 syscall
(gdb) c
Continuing.
[New Thread 0x7ffff7c5f640 (LWP 2915524)]
[Thread 0x7ffff7c5f640 (LWP 2915510) exited]
[Switching to Thread 0x7ffff7c5f640 (LWP 2915524)]
Thread 3 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
68 syscall
(gdb) c
Continuing.
[New Thread 0x7ffff7c5f640 (LWP 2915616)]
[Thread 0x7ffff7c5f640 (LWP 2915524) exited]
[Switching to Thread 0x7ffff7c5f640 (LWP 2915616)]
Thread 4 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
68 syscall
(gdb) c
Continuing.
... hangs ...
The first two times we do "continue", we displaced-step the syscall
instruction that causes the thread to exit. When the thread exits,
the main thread, waiting on pthread_join, is unblocked. It spawns a
new thread, which hits the breakpoint on the syscall again. However,
infrun was never notified that the displaced-stepping threads are done
using the displaced-step buffer, so now both buffers are marked as
used. So when we do the third continue, there are no buffers
available to displaced-step the syscall, so the thread waits forever
for its turn.
When trying the same but with in-line step over (displaced-stepping
disabled):
$ ./gdb -q -nx --data-directory=data-directory \
build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit \
-ex "b my_exit_syscall" -ex "set displaced-stepping off" -ex r
Reading symbols from build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit...
Breakpoint 1 at 0x123c: file src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S, line 68.
Starting program: build/binutils-gdb/gdb/testsuite/outputs/gdb.threads/step-over-thread-exit/step-over-thread-exit
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/../lib/libthread_db.so.1".
[New Thread 0x7ffff7c5f640 (LWP 2928290)]
[Switching to Thread 0x7ffff7c5f640 (LWP 2928290)]
Thread 2 "step-over-threa" hit Breakpoint 1, my_exit_syscall () at src/binutils-gdb/gdb/testsuite/lib/my-syscalls.S:68
68 syscall
(gdb) c
Continuing.
[Thread 0x7ffff7c5f640 (LWP 2928290) exited]
No unwaited-for children left.
(gdb) i th
Id Target Id Frame
1 Thread 0x7ffff7c60740 (LWP 2928285) "step-over-threa" 0x00007ffff7f7c9b7 in __pthread_clockjoin_ex () from /usr/lib/libpthread.so.0
The current thread <Thread ID 2> has terminated. See `help thread'.
(gdb) thread 1
[Switching to thread 1 (Thread 0x7ffff7c60740 (LWP 2928285))]
#0 0x00007ffff7f7c9b7 in __pthread_clockjoin_ex () from /usr/lib/libpthread.so.0
(gdb) c
Continuing.
^C^C
... hangs ...
The "continue" causes an in-line step to occur, meaning the main
thread is stopped while we step the syscall. The stepped thread exits
when executing the syscall, the linux-nat target notices there are no
more resumed threads to be waited for, so returns
TARGET_WAITKIND_NO_RESUMED, which causes the prompt to return. But
infrun never clears the in-line step over info. So if we try
continuing the main thread, GDB doesn't resume it, because it thinks
there's an in-line step in progress that we need to wait for to
finish, and we are stuck there.
To fix this, infrun needs to be informed when a thread doing a
displaced or in-line step over exits. We can do that with the new
target_set_thread_options mechanism which is optimal for only enabling
exit events of the thread that needs it; or, if that is not supported,
by using target_thread_events, which enables thread exit events for
all threads. This is done by this commit.
This patch then modifies handle_inferior_event in infrun.c to clean up
any step-over the exiting thread might have been doing at the time of
the exit. The cases to consider are:
- the exiting thread was doing an in-line step-over with an all-stop
target
- the exiting thread was doing an in-line step-over with a non-stop
target
- the exiting thread was doing a displaced step-over with a non-stop
target
The displaced-stepping buffer implementation in displaced-stepping.c
is modified to account for the fact that it's possible that we
"finish" a displaced step after a thread exit event. The buffer that
the exiting thread was using is marked as available again and the
original instructions under the scratch pad are restored. However, it
skips applying the fixup, which wouldn't make sense since the thread
does not exist anymore.
Another case that needs handling is if a displaced-stepping thread
exits, and the event is reported while we are in stop_all_threads. We
should call displaced_step_finish in the handle_one function, in that
case. It was already called in other code paths, just not the "thread
exited" path.
This commit doesn't make infrun ask the target to report the
TARGET_WAITKIND_THREAD_EXITED events yet, that'll be done later in the
series.
Note that "stop_print_frame = false;" line is moved to normal_stop,
because TARGET_WAITKIND_THREAD_EXITED can also end up with the event
transmorphed into TARGET_WAITKIND_NO_RESUMED. Moving it to
normal_stop keeps it centralized.
Co-authored-by: Simon Marchi <simon.marchi@efficios.com>
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I745c6955d7ef90beb83bcf0ff1d1ac8b9b6285a5
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This implements support for the new GDB_THREAD_OPTION_EXIT thread
option for native Linux.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ia69fc0b9b96f9af7de7cefc1ddb1fba9bbb0bb90
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
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When stepping over a breakpoint with displaced stepping, GDB needs to
be informed if the stepped thread exits, otherwise the displaced
stepping buffer that was allocated to that thread leaks, and this can
result in deadlock, with other threads waiting for their turn to
displaced step, but their turn never comes.
Similarly, when stepping over a breakpoint in line, GDB also needs to
be informed if the stepped thread exits, so that is can clear the step
over state and re-resume threads.
This commit makes it possible for GDB to ask the target to report
thread exit events for a given thread, using the new "thread options"
mechanism introduced by a previous patch.
This only adds the core bits. Following patches in the series will
teach the Linux backends (native & gdbserver) to handle the
GDB_THREAD_OPTION_EXIT option, and then a later patch will make use of
these thread exit events to clean up displaced stepping and inline
stepping state properly.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I96b719fdf7fee94709e98bb3a90751d8134f3a38
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27338
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Currently, infrun assumes that when TARGET_WAITKIND_THREAD_EXITED is
reported, the corresponding GDB thread has already been removed from
the GDB thread list.
Later in the series, that will no longer work, as infrun will need to
refer to the thread's thread_info when it processes
TARGET_WAITKIND_THREAD_EXITED.
As preparation, this patch makes deleting the GDB thread
responsibility of infrun, instead of the target.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I013d87f61ffc9aaca49f0d6ce2a43e3ea69274de
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Currently, GDB does not understand the THREAD_EXITED stop reply in
remote all-stop mode. There's no good reason for this, it just
happened that THREAD_EXITED was only ever reported in non-stop mode so
far. This patch teaches GDB to parse that event in all-stop RSP too.
There is no need to add a qSupported feature for this, because the
server won't send a THREAD_EXITED event unless GDB explicitly asks for
it, with QThreadEvents, or with the GDB_THREAD_OPTION_EXIT
QThreadOptions option added in the next patch.
Change-Id: Ide5d12391adf432779fe4c79526801c4a5630966
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Now that gdb/19675 is fixed for both native and gdbserver GNU/Linux,
remove the gdb/19675 kfails.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I95c1c38ca370100675d303cd3c8995860bef465d
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This patch teaches the Linux GDBserver backend to report clone events
to GDB, when GDB has requested them with the GDB_THREAD_OPTION_CLONE
thread option, via the new QThreadOptions packet.
This shuffles code in linux_process_target::handle_extended_wait
around to a more logical order when we now have to handle and
potentially report all of fork/vfork/clone.
Raname lwp_info::fork_relative -> lwp_info::relative as the field is
no longer only about (v)fork.
With this, gdb.threads/stepi-over-clone.exp now cleanly passes against
GDBserver, so remove the native-target-only requirement from that
testcase.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: I3a19bc98801ec31e5c6fdbe1ebe17df855142bb2
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This commit teaches the native Linux target about the
GDB_THREAD_OPTION_CLONE thread option. It's actually simpler to just
continue reporting all clone events unconditionally to the core.
There's never any harm in reporting a clone event when the option is
disabled. All we need to do is to report support for the option,
otherwise GDB falls back to use target_thread_events().
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: If90316e2dcd0c61d0fefa0d463c046011698acf9
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A previous patch taught GDB about a new TARGET_WAITKIND_THREAD_CLONED
event kind, and made the Linux target report clone events.
A following patch will teach Linux GDBserver to do the same thing.
However, for remote debugging, it wouldn't be ideal for GDBserver to
report every clone event to GDB, when GDB only cares about such events
in some specific situations. Reporting clone events all the time
would be potentially chatty. We don't enable thread create/exit
events all the time for the same reason. Instead we have the
QThreadEvents packet. QThreadEvents is target-wide, though.
This patch makes GDB instead explicitly request that the target
reports clone events or not, on a per-thread basis.
In order to be able to do that with GDBserver, we need a new remote
protocol feature. Since a following patch will want to enable thread
exit events on per-thread basis too, the packet introduced here is
more generic than just for clone events. It lets you enable/disable a
set of options at once, modelled on Linux ptrace's PTRACE_SETOPTIONS.
IOW, this commit introduces a new QThreadOptions packet, that lets you
specify a set of per-thread event options you want to enable. The
packet accepts a list of options/thread-id pairs, similarly to vCont,
processed left to right, with the options field being a number
interpreted as a bit mask of options. The only option defined in this
commit is GDB_THREAD_OPTION_CLONE (0x1), which ask the remote target
to report clone events. Another patch later in the series will
introduce another option.
For example, this packet sets option "1" (clone events) on thread
p1000.2345:
QThreadOptions;1:p1000.2345
and this clears options for all threads of process 1000, and then sets
option "1" (clone events) on thread p1000.2345:
QThreadOptions;0:p1000.-1;1:p1000.2345
This clears options of all threads of all processes:
QThreadOptions;0
The target reports the set of supported options by including
"QThreadOptions=<supported options>" in its qSupported response.
infrun is then tweaked to enable GDB_THREAD_OPTION_CLONE when stepping
over a breakpoint.
Unlike PTRACE_SETOPTIONS, fork/vfork/clone children do NOT inherit
their parent's thread options. This is so that GDB can send e.g.,
"QThreadOptions;0;1:TID" without worrying about threads it doesn't
know about yet.
Documentation for this new remote protocol feature is included in a
documentation patch later in the series.
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=19675
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=27830
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Ie41e5093b2573f14cf6ac41b0b5804eba75be37e
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Similarly to QProgramSignals and QPassSignals, avoid sending duplicate
QThreadEvents packets.
Approved-By: Andrew Burgess <aburgess@redhat.com>
Change-Id: Iaf5babb0b64e1527ba4db31aac8674d82b17e8b4
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