When building master GDB, I ran into the following:
binutils-gdb/gdb/bt-utils.c: In function 'int libbacktrace_print(void*, uintptr_t, const char*, int, const char*)':
binutils-gdb/gdb/bt-utils.c:93:44: error: format '%lx' expects argument of type 'long unsigned int', but argument 4 has type 'uintptr_t {aka unsigned int}' [-Werror=format=]
snprintf (buf, sizeof (buf), "0x%lx ", pc);
Fix this by using %PRIxPTR as opposed to %lx.
In read_call_site_scope we have:
...
call_site_local.pc = pc;
slot = htab_find_slot (cu->call_site_htab, &call_site_local, INSERT);
...
The call passes a call_site pointer as element. OTOH, the hashtab is created
using hash_f == core_addr_hash and eq_f == core_addr_eq, so the element
will be accessed through a CORE_ADDR pointer.
This is not wrong (at least in C), given that pc is the first field in
call_site.
Nevertheless, as in call_site_for_pc, make the htab_find_slot call match the
used hash_f and eq_f by using &pc instead:
...
slot = htab_find_slot (cu->call_site_htab, &pc, INSERT);
...
Tested on x86_64-linux.
Co-Authored-By: Tom de Vries <tdevries@suse.de>
Change how rnglists and loclists procs to align them with how procs for
aranges (and other things in the DWARF assembler) work. Instead of
using "args" (variable number of parameters in TCL) and command-line
style option arguments, use one leading "option" parameters, used as a
kind of key/value dictionary of options parsed using `parse_options`.
Change-Id: I63e60d17ae16a020ce4d6de44baf3d152ea42a1a
When I wrote support for rnglists and loclists in the testsuite's DWARF
assembler, I made it with nested procs, for example proc "table" inside
proc "rnglists". The intention was that this proc "table" could only be
used by the user while inside proc "rnglists"'s body. I had chosen very
simple names, thinking there was no chance of name clashes. I recently
learned that this is not how TCL works. This ends up defining a proc
"table" in the current namespace ("Dwarf" in this case).
Things still work if you generate rnglists and loclists in the same
file, as each redefines its own procedures when executing. But if a
user of the assembler happened to define a convenience "table" or
"start_end" procedure, for example, it would get overriden.
I'd like to change how this works to reduce the chances of a name clash.
- Move the procs out of each other, so they are not defined in a nested
fashion.
- Prefix them with "_rnglists_" or "_loclists_".
- While calling $body in the various procs, temporarily make the procs
available under their "short" name. For example, while in rngllists'
body, make _rnglists_table available as just "table". This allows
existing code to keep working and keeps it not too verbose.
- Modify with_override to allow the overriden proc to not exist. In
that case, the temporary proc is deleted on exit.
Note the non-conforming indentation when calling with_override in
_loclists_list. This is on purpose: as we implement more loclists (and
rnglists) entry types, the indentation would otherwise get larger and
larger without much value for readability. So I think it's reasonable
here to put them on the same level.
Change-Id: I7bb48d26fcb0dba1ae4dada05c0c837212424328
Remove the `TYPE_FIELD_NAME` and `FIELD_NAME` macros, changing all the
call sites to use field::name directly.
Change-Id: I6900ae4e1ffab1396e24fb3298e94bf123826ca6
Add the `name` and `set_name` methods on `struct field`, in order to
remove `FIELD_NAME` and `TYPE_FIELD_NAME` macros. In this patch, the
macros are changed to use `field::name`, so all the call sites that are
used to set the field's name are changed to use `field::set_name`.
The next patch will remove the macros completely.
Note that because of the name clash between the existing field named
`name` and the new method, I renamed the field `m_name`. It is not
private per-se, because we can't make `struct field` a non-POD yet, but
it should be considered private anyway (not accessed outside `struct
field`).
Change-Id: If16ddbca4e0c39d0ff9da420bb5cdebe5b9b0896
PR gdb/28369 reports that gdb/ser-pipe.c has an 'execl' function call
with a hard-coded "/bin/sh" as its argument. We've had 'get_shell'
for a while now, which is conscious about the SHELL environment and a
better alternative to always calling "/bin/sh".
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=28369
Patch is adding Cortex-R52+ as 'cortex-r52plus' command line
flag for -mcpu option.
bfd/
* cpu-arm.c: New Cortex-R52+ CPU.
gas/
* NEWS: Update docs.
* config/tc-arm.c: New Cortex-R52+ CPU.
* doc/c-arm.texi: Update docs.
* testsuite/gas/arm/cpu-cortex-r52plus.d: New test.
Patch is adding new 'armv9-a` command line flag to -march for AArch64.
gas/
* config/tc-aarch64.c: Add 'armv9-a' command line flag.
* docs/c-aarch64.text: Update docs.
* NEWS: Update docs.
include/
* opcode/aarch64.h (AARCH64_FEATURE_V9): New define.
(AARCH64_ARCH_V9): New define.
As follow-up to this discussion:
https://sourceware.org/pipermail/gdb-patches/2020-August/171385.html
... make runto_main not pass no-message to runto. This means that if we
fail to run to main, for some reason, we'll emit a FAIL. This is the
behavior we want the majority of (if not all) the time.
Without this, we rely on tests logging a failure if runto_main fails,
otherwise. They do so in a very inconsisteny mannet, sometimes using
"fail", "unsupported" or "untested". The messages also vary widly.
This patch removes all these messages as well.
Also, remove a few "fail" where we call runto (and not runto_main). by
default (without an explicit no-message argument), runto prints a
failure already. In two places, gdb.multi/multi-re-run.exp and
gdb.python/py-pp-registration.exp, remove "message" passed to runto.
This removes a few PASSes that we don't care about (but FAILs will still
be printed if we fail to run to where we want to). This aligns their
behavior with the rest of the testsuite.
Change-Id: Ib763c98c5f4fb6898886b635210d7c34bd4b9023
Make gdb_open_cloexec return a scoped_fd, to encourage using automatic
management of the file descriptor closing. Except in the most trivial
cases, I changed the callers to just release the fd, which retains their
existing behavior. That will allow the transition to using scoped_fd
more to go gradually, one caller at a time.
Change-Id: Ife022b403f96e71d5ebb4f1056ef6251b30fe554
The following patches wants to change gdb_fopen_cloexec and
gdb_mkostemp_cloexec to return a scoped_fd. Doing this causes a cyclic
include between scoped_fd.h and filestuff.h, that both want to include
each other. scoped_fd.h includes filestuff.h because of the
scoped_fd::to_file method's return value. filestuff.h would then
include scoped_fd.h for gdb_fopen_cloexec's and gdb_mkostemp_cloexec's
return values.
To fix that, move gdb_file_up to its own file, gdb_file.h.
Change-Id: Ic82a48914b2aacee8f14af535b7469245f88b93d
My commit 261980de18 added alignment for the resource table symbol.
But it is wrong. The Linux remoteproc driver loads and interprets the
contents of the .resource_table ELF section, not of a table symbol.
Without this patch, if the linker happens to output padding for symbol
alignment, then the resource table contents as viewed by the kernel
loader would "shift" and look corrupted.
ld/ChangeLog:
* scripttempl/pru.sc (.resource_table): Align the output
section, not the first symbol.
Signed-off-by: Dimitar Dimitrov <dimitar@dinux.eu>
The "make thread_suspend_state::stop_pc optional" patch caused a
regression on Windows when using shared libraries. I tracked this
down to an unguarded use of stop_pc() in the TARGET_WAITKIND_LOADED
case of handle_inferior_event. This patch fixes the bug by ensuring
that the stop PC is set at this point.
With running test-case gdb.debuginfod/fetch_src_and_symbols.exp with target
board unix/-bad, I get:
...
gcc: error: unrecognized command line option '-bad'^M
compiler exited with status 1
gdb compile failed, gcc: error: unrecognized command line option '-bad'
FAIL: gdb.debuginfod/fetch_src_and_symbols.exp: compile
...
Replace the FAIL with the usual:
...
UNTESTED: gdb.debuginfod/fetch_src_and_symbols.exp: failed to compile
...
Tested on x86_64-linux.
When running test-case gdb.base/info-os.exp with target board unix/-bad, I run
into:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.base/info-os.exp: failed to prepare
FAIL: gdb.base/info-os.exp: cannot compile test program
...
Remove the redundant FAIL.
Tested on x86_64-linux.
When running test-case gdb.base/info-os.exp, I run into:
...
PASS: gdb.base/info-os.exp: get threads
PASS: gdb.base/info-os.exp: get threads
DUPLICATE: gdb.base/info-os.exp: get threads
...
Fix this not doing pass followed by exp_continue in gdb_test_multiple.
Tested on x86_64-linux.
When running test-case gdb.dwarf2/dw2-opt-structptr.exp with target board
unix/-bad, I get:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.dwarf2/dw2-opt-structptr.exp: dw2-opt-structptr.exp
UNTESTED: gdb.dwarf2/dw2-opt-structptr.exp: failed to compile
ERROR: (dw2-opt-structptr) No such file or directory
UNRESOLVED: gdb.dwarf2/dw2-opt-structptr.exp: console: set print object on
...
Merge the two UNTESTEDs.
Fix the UNRESOLVED by checking result of compilation.
Tested on x86_64-linux.
When running test-case gdb.base/structs.exp with target board unix/-bad, I
get:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.base/structs.exp: failed to prepare
ERROR: tcl error sourcing src/gdb/testsuite/gdb.base/structs.exp.
ERROR: can't read "use_gdb_stub": no such variable
...
Fix this by checking the compilation result.
Fix the resulting DUPLICATEs using with_test_prefix.
Tested on x86_64-linux.
When running test-case gdb.base/cvexpr.exp with target board unix/-bad, I get:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
ERROR: tcl error sourcing src/gdb/testsuite/gdb.base/cvexpr.exp.
ERROR: can't read "use_gdb_stub": no such variable
...
This is triggered in a part of the test that claims to require no debug
information, but uses the exec containing either dwarf or ctf.
Fix this by preparing another executable compiled with nodebug, and using
that one instead.
Also use with_test_prefix to mark the nodebug part, such that we have:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.base/cvexpr.exp: dwarf: failed to prepare
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.base/cvexpr.exp: nodebug: failed to prepare
...
Tested on x86_64-linux.
When running test-case gdb.base/call-sc.exp with target board unix/-bad, I
get:
...
gdb compile failed, gcc: error: unrecognized command line option '-bad'
UNTESTED: gdb.base/call-sc.exp: failed to prepare
ERROR: tcl error sourcing src/gdb/testsuite/gdb.base/call-sc.exp.
ERROR: can't read "use_gdb_stub": no such variable
...
Fix this by checking the compilation result.
Fix the resulting DUPLICATE:
...
DUPLICATE: gdb.base/call-sc.exp: failed to prepare
...
using with_test_prefix.
Tested on x86_64-linux.
The effect of:
...
untested "y.exp"
...
in a gdb.x/y.exp is:
...
UNTESTED: gdb.x/y.exp: y.exp
...
which is a bit pointless.
Replace these untested messages in gdb.mi/*.exp with the usual "failed to
compile".
Likewise for an:
...
untested $testname
...
where the variable is undefined.
Tested on x86_64-linux.
On ubuntu 18.04.5, I run into:
...
(gdb) mt print objfiles dwindex^M
^M
Object file build/gdb/testsuite/outputs/gdb.rust/dwindex/dwindex: \
Objfile at 0x55dab0b87a50, bfd at 0x55dab0b0cfa0, 1095 minsyms^M
^M
Psymtabs:^M
vendor/compiler_builtins/src/int/specialized_div_rem/mod.rs at 0x55dab0db0720^M
...
library/std/src/sys/unix/stdio.rs at 0x55dab0d96320^M
ERROR: internal buffer is full.
UNRESOLVED: gdb.rust/dwindex.exp: check if index present
...
Fix this by using -lbl in proc ensure_gdb_index.
Tested on x86_64-linux.
Add elfcore_grok_solaris_note function that enables to
obtain process status, register values, and program info
from Solaris's core files.
bfd/
* elf.c (elfcore_grok_solaris_note): Solaris specific ELF
note parser. Better GDB's coredump analysis on Solaris...
(elfcore_grok_solaris_note_impl): New function.
(elfcore_grok_solaris_prstatus): New function.
(elfcore_grok_solaris_info): New function.
(elfcore_grok_solaris_lwpstatus): New function.
(elf_parse_notes): Added "CORE" groker element.
include/
* elf/common.h: Add note segment constants for core files on
Solaris systems.
When running test-case gdb.base/break-interp.exp on openSUSE Leap 42.3, I get:
...
(gdb) info addr dl_main^M
Symbol "dl_main" is at 0x1750 in a file compiled without debugging.^M
(gdb) FAIL: gdb.base/break-interp.exp: info addr dl_main
...
while the regexp expects "Symbol \"dl_main\" is a function at address $hex\\."
Fix this by also accepting this variant.
Tested on x86_64-linux.
The gdb.multi/multi-term-settings.exp testcase sometimes fails like so:
Running /home/pedro/gdb/mygit/src/gdb/testsuite/gdb.multi/multi-term-settings.exp ...
FAIL: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: stop with control-c (SIGINT)
It's easier to reproduce if you stress the machine at the same time, like e.g.:
$ stress -c 24
Looking at gdb.log, we see:
(gdb) attach 60422
Attaching to program: build/gdb/testsuite/outputs/gdb.multi/multi-term-settings/multi-term-settings, process 60422
[New Thread 60422.60422]
Reading symbols from /lib/x86_64-linux-gnu/libc.so.6...
Reading symbols from /usr/lib/debug//lib/x86_64-linux-gnu/libc-2.31.so...
Reading symbols from /lib64/ld-linux-x86-64.so.2...
(No debugging symbols found in /lib64/ld-linux-x86-64.so.2)
0x00007f2fc2485334 in __GI___clock_nanosleep (clock_id=<optimized out>, clock_id@entry <mailto:clock_id@entry>=0, flags=flags@entry <mailto:flags@entry>=0, req=req@entry <mailto:req@entry>=0x7ffe23126940, rem=rem@entry <mailto:rem@entry>=0x0) at ../sysdeps/unix/sysv/linux/clock_nanosleep.c:78
78 ../sysdeps/unix/sysv/linux/clock_nanosleep.c: No such file or directory.
(gdb) PASS: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: inf2: attach
set schedule-multiple on
(gdb) PASS: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: set schedule-multiple on
info inferiors
Num Description Connection Executable
1 process 60404 1 (extended-remote localhost:2349) build/gdb/testsuite/outputs/gdb.multi/multi-term-settings/multi-term-settings
* 2 process 60422 1 (extended-remote localhost:2349) build/gdb/testsuite/outputs/gdb.multi/multi-term-settings/multi-term-settings
(gdb) PASS: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: info inferiors
pid=60422, count=46
pid=60422, count=47
pid=60422, count=48
pid=60422, count=49
pid=60422, count=50
pid=60422, count=51
pid=60422, count=52
pid=60422, count=53
pid=60422, count=54
pid=60422, count=55
pid=60422, count=56
pid=60422, count=57
pid=60422, count=58
pid=60422, count=59
pid=60422, count=60
pid=60422, count=61
pid=60422, count=62
pid=60422, count=63
pid=60422, count=64
pid=60422, count=65
pid=60422, count=66
pid=60422, count=67
pid=60422, count=68
pid=60422, count=69
pid=60404, count=54
pid=60404, count=55
pid=60404, count=56
pid=60404, count=57
pid=60404, count=58
PASS: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: continue
Quit
(gdb) FAIL: gdb.multi/multi-term-settings.exp: inf1_how=attach: inf2_how=attach: stop with control-c (SIGINT)
If you look at the testcase's sources, you'll see that the intention
is to resumes the program with "continue", wait to see a few of those
"pid=..., count=..." lines, and then interrupt the program with
Ctrl-C. But somehow, that resulted in GDB printing "Quit", instead of
the Ctrl-C stopping the program with SIGINT.
Here's what is happening:
#1 - those "pid=..., count=..." lines we see above weren't actually
output by the inferior after it has been continued (see #1).
Note that "inf1_how" and "inf2_how" are "attach". What happened
is that those "pid=..., count=..." lines were output by the
inferiors _before_ they were attached to. We see them at that
point instead of earlier, because that's where the testcase
reads from the inferiors' spawn_ids.
#2 - The testcase mistakenly thinks those "pid=..., count=..." lines
happened after the continue was processed by GDB, meaning it has
waited enough, and so sends the Ctrl-C. GDB hasn't yet passed
the terminal to the inferior, so the Ctrl-C results in that
Quit.
The fix here is twofold:
#1 - flush inferior output right after attaching
#2 - consume the "Continuing" printed by "continue", indicating the
inferior has the terminal. This is the same as done throughout
the testsuite to handle this exact problem of sending Ctrl-C too
soon.
gdb/testsuite/ChangeLog:
yyyy-mm-dd Pedro Alves <pedro@palves.net <mailto:pedro@palves.net>>
* gdb.multi/multi-term-settings.exp (create_inferior): Flush
inferior output.
(coretest): Use $gdb_test_name. After issuing "continue", wait
for "Continuing".
Change-Id: Iba7671dfe1eee6b98d29cfdb05a1b9aa2f9defb9
I build gdb without xml support using --without-expat, and ran into:
...
(gdb) target remote | vgdb --wait=2 --max-invoke-ms=2500 --pid=22032^M
Remote debugging using | vgdb --wait=2 --max-invoke-ms=2500 --pid=22032^M
relaying data between gdb and process 22032^M
warning: Can not parse XML target description; XML support was disabled at \
compile time^M
...
(gdb) PASS: gdb.base/valgrind-infcall.exp: continue #1
p gdb_test_infcall ()^M
Remote 'g' packet reply is too long (expected 560 bytes, got 800 bytes): ...^M
(gdb) FAIL: gdb.base/valgrind-infcall.exp: p gdb_test_infcall ()
...
After googling the error message with context valgrind gdbserver, I found
indications that the Remote 'g' packet reply error is due to missing xml
support.
And here ( https://www.valgrind.org/docs/manual/manual-core-adv.html ) I
found:
...
GDB version needed for ARM and PPC32/64.
You must use a GDB version which is able to read XML target description sent
by a gdbserver. This is the standard setup if GDB was configured and built
with the "expat" library. If your GDB was not configured with XML support, it
will report an error message when using the "target" command. Debugging will
not work because GDB will then not be able to fetch the registers from the
Valgrind gdbserver.
...
So I guess I'm running into the same problem for x86_64.
Fix this by skipping all gdb.base/valgrind-*.exp tests if xml support is not
available. Although only the gdb.base/valgrind-infcall*.exp produce fails,
the Remote 'g' packet reply error occurs in all tests, so it seems prudent to
disable them all.
Tested on x86_64-linux.
With a gdb build using python 2.7, I run into:
...
(gdb) python \
gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))^M
File "<string>", line 1^M
gdb.events.breakpoint_modified.connect(lambda bp: print(bp.enabled))^M
^^M
SyntaxError: invalid syntax^M
Error while executing Python code.^M
(gdb) FAIL: gdb.python/py-breakpoint.exp: test_bkpt_auto_disable: \
trap breakpoint_modified event
...
This is caused by the following:
- a lambda function body needs to be an expression
- in python 2, print is a statement, while in python 3 it's a function
- a function call is an expression, and a statement is not.
Fix this by defining a function print_bp_enabled:
...
def print_bp_enabled (bp):
print (bp.enabled)
end
...
and using that instead.
Tested on x86_64-linux.
With a gdb configured to be somewhat minimal, while still supporting python:
...
$ gdb --configuration
This GDB was configured as follows:
configure --host=x86_64-pc-linux-gnu --target=x86_64-pc-linux-gnu
--with-auto-load-dir=$debugdir:$datadir/auto-load
--with-auto-load-safe-path=$debugdir:$datadir/auto-load
--without-expat
--with-gdb-datadir=$install/share/gdb (relocatable)
--with-jit-reader-dir=$install/lib64/gdb (relocatable)
--without-libunwind-ia64
--without-lzma
--without-babeltrace
--without-intel-pt
--with-mpfr
--without-xxhash
--with-python=/usr
--with-python-libdir=/usr/lib
--with-debuginfod
--without-guile
--disable-source-highlight
--with-separate-debug-dir=/usr/lib/debug
--with-system-gdbinit=$devel/system-gdbinit
...
and using gcc 4.8 to build gdb (causing std::thread not to be used due to
PR28318) I ran into:
...
(gdb) PASS: gdb.gdb/python-helper.exp: start inner gdb
print 1^M
^M
Breakpoint 2, value_print () at src/gdb/valprint.c:1174^M
1174 scoped_value_mark free_values;^M
(xgdb) FAIL: gdb.gdb/python-helper.exp: hit breakpoint in inner gdb (timeout)
...
The problem is that the regexp expects "hit Breakpoint $decimal". The "hit"
part is missing.
The "hit" is printed by maybe_print_thread_hit_breakpoint, when
show_thread_that_caused_stop returns true:
...
int
show_thread_that_caused_stop (void)
{
return highest_thread_num > 1;
}
...
Apparently, that's not the case.
Fix this by removing "hit" from the regexp, making the regexp more similar to
what is used in say, continue_to_breakpoint.
Tested on x86_64-linux.
In this commit:
commit abbbd4a3e0
Date: Wed Aug 11 13:24:33 2021 +0100
gdb: use libbacktrace to create a better backtrace for fatal signals
The build of GDB was broken iff, the execinfo backtrace API is not
available, and, libbacktrace is either disabled, or not usable. In
this case you'll see build errors like this:
CXX bt-utils.o
/home/username/src/binutils-gdb/gdb/bt-utils.c: In function 'void gdb_internal_backtrace()':
/home/username/src/binutils-gdb/gdb/bt-utils.c:165:5: error: 'gdb_internal_backtrace_1' was not declared in this scope
gdb_internal_backtrace_1 ();
^~~~~~~~~~~~~~~~~~~~~~~~
This commit fixes the issue by guarding the call to
gdb_internal_backtrace_1 with '#ifdef GDB_PRINT_INTERNAL_BACKTRACE',
which is only defined when one of the backtrace libraries are
available.
With this commit:
commit 91f2597bd2
Date: Thu Aug 12 18:24:59 2021 +0100
gdb: print backtrace for internal error/warning
I included some references to 'stderr', which, it was pointed out,
would be better written as 'standard error stream'. See:
https://sourceware.org/pipermail/gdb-patches/2021-September/182225.html
This commit replaces the two instances of 'stderr' that I introduced.
In a recent commit I used 'manor' in some comments rather than
'manner'. This commit fixes those two mistakes.
I also looked through the gdb/ tree and found one additional instance
of this mistake that this commit also fixes.
For DWARF revision 4 and earlier, display_debug_lines_decoded
populates the file_table array with entries read from .debug_line
after the directory table. file_table[0] contains the first entry.
DWARF rev 4 line number programs index this entry as file number one.
DWARF revision 5 changes .debug_line format quite extensively, and in
particular gives file number zero a meaning.
PR 27202
* dwarf.c (display_debug_lines_decoded): Correct indexing used
for DWARF5 files.
The following scenario hangs:
- maint set target-non-stop on
- `gdbserver --attach`
- a multi-threaded program
For example:
Terminal 1:
$ gnome-calculator&
[1] 495731
$ ../gdbserver/gdbserver --once --attach :1234 495731
Attached; pid = 495731
Listening on port 1234
Terminal 2:
$ ./gdb -nx -q --data-directory=data-directory /usr/bin/gnome-calculator -ex "maint set target-non-stop on" -ex "tar rem :1234"
Reading symbols from /usr/bin/gnome-calculator...
(No debugging symbols found in /usr/bin/gnome-calculator)
Remote debugging using :1234
* hangs *
What happens is:
- The protocol between gdb and gdbserver is in non-stop mode, but the
user-visible behavior is all-stop
- On connect, gdbserver sends one stop reply for one thread that is
stops, the others stay running
- In process_initial_stop_replies, gdb calls stop_all_threads to stop
these other threads, because we are using the all-stop user-visible
mode
- stop_all_threads sends a stop request for all the running threads and
then waits for resulting events
- At this point, the remote target is in target_async(0) mode, which
makes stop_all_threads not consider it for events
- stop_all_threads loops indefinitely (it does not even block
indefinitely, it is in an infinite busy loop) because there are no
event sources. wait_one_event returns a TARGET_WAITKIND_NO_RESUMED
wait status.
Fix that by making the remote target async around the stop_all_threads
call.
I haven't implemented it because I'm not sure how to do it, but I think
it would be a good idea to have, in stop_all_threads / wait_one /
handle_one, an assert to check that if we are expecting one or more
event, then there are some targets that are in a state where they can
supply some events. Otherwise, we'll necessarily be stuck in this
infinite loop, and it's probably due to a bug in GDB. I'm not too sure
where to put this or how to express it though. Perhaps in
stop_all_threads, here:
for (int i = 0; i < waits_needed; i++)
{
wait_one_event event = wait_one ();
*here*
if (handle_one (event))
break;
}
If at that point, the returned event is TARGET_WAITKIND_NO_RESUMED,
there's a problem. We expect some event, because we've asked some
threads to stop, but all targets are answering that they won't have any
events for us. That's a contradiction, and a sign that something has
gone wrong. It could perhaps event be:
gdb_assert (event.ws.kind != TARGET_WAITKIND_NO_RESUMED);
in handle_one, as the idea is the same in prepare_for_detach.
A bit more sophisticated would be: we know which targets we are
expecting waits from, since we know which threads we have asked to
stop. So if any of these targets returns TARGET_WAITKIND_NO_RESUMED,
something is fishy.
Add a test that tests attaching with gdbserver's --attach flag to a
multi-threaded program, and then connecting to it. Without the fix, the
test reproduces the hang.
Change-Id: If6f6690a4887ca66693ef1af64791dda4c65f24f
