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7f15a94e65
For background, see this thread: https://inbox.sourceware.org/gdb-patches/20250612144607.27507-1-tdevries@suse.de Tom describes the issue clearly in the above thread, here's what he said: Once in a while, when running test-case gdb.base/bp-cmds-continue-ctrl-c.exp, I run into: ... Breakpoint 2, foo () at bp-cmds-continue-ctrl-c.c:23^M 23 usleep (100);^M ^CFAIL: $exp: run: stop with control-c (unexpected) (timeout) FAIL: $exp: run: stop with control-c ... This is PR python/32167, observed both on x86_64-linux and powerpc64le-linux. This is not a timeout due to accidental slowness, gdb actually hangs. The backtrace at the hang is (on cfarm120 running AlmaLinux 9.6): ... (gdb) bt #0 0x00007fffbca9dd94 in __lll_lock_wait () from /lib64/glibc-hwcaps/power10/libc.so.6 #1 0x00007fffbcaa6ddc in pthread_mutex_lock@@GLIBC_2.17 () from /lib64/glibc-hwcaps/power10/libc.so.6 #2 0x000000001067aee8 in __gthread_mutex_lock () at /usr/include/c++/11/ppc64le-redhat-linux/bits/gthr-default.h:749 #3 0x000000001067afc8 in __gthread_recursive_mutex_lock () at /usr/include/c++/11/ppc64le-redhat-linux/bits/gthr-default.h:811 #4 0x000000001067b0d4 in std::recursive_mutex::lock () at /usr/include/c++/11/mutex:108 #5 0x000000001067b380 in std::lock_guard<std::recursive_mutex>::lock_guard () at /usr/include/c++/11/bits/std_mutex.h:229 #6 0x0000000010679d3c in set_quit_flag () at gdb/extension.c:865 #7 0x000000001066b6dc in handle_sigint () at gdb/event-top.c:1264 #8 0x00000000109e3b3c in handler_wrapper () at gdb/posix-hdep.c:70 #9 <signal handler called> #10 0x00007fffbcaa6d14 in pthread_mutex_lock@@GLIBC_2.17 () from /lib64/glibc-hwcaps/power10/libc.so.6 #11 0x000000001067aee8 in __gthread_mutex_lock () at /usr/include/c++/11/ppc64le-redhat-linux/bits/gthr-default.h:749 #12 0x000000001067afc8 in __gthread_recursive_mutex_lock () at /usr/include/c++/11/ppc64le-redhat-linux/bits/gthr-default.h:811 #13 0x000000001067b0d4 in std::recursive_mutex::lock () at /usr/include/c++/11/mutex:108 #14 0x000000001067b380 in std::lock_guard<std::recursive_mutex>::lock_guard () at /usr/include/c++/11/bits/std_mutex.h:229 #15 0x00000000106799cc in set_active_ext_lang () at gdb/extension.c:775 #16 0x0000000010b287ac in gdbpy_enter::gdbpy_enter () at gdb/python/python.c:232 #17 0x0000000010a8e3f8 in bpfinishpy_handle_stop () at gdb/python/py-finishbreakpoint.c:414 ... What happens here is the following: - the gdbpy_enter constructor attempts to set the current extension language to python using set_active_ext_lang - set_active_ext_lang attempts to lock ext_lang_mutex - while doing so, it is interrupted by sigint_wrapper (the SIGINT handler), handling a SIGINT - sigint_wrapper calls handle_sigint, which calls set_quit_flag, which also tries to lock ext_lang_mutex - since std::recursive_mutex::lock is not async-signal-safe, things go wrong, resulting in a hang. The hang bisects to commit |
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| .. | ||
| lib/gdb | ||
| py-all-events.def | ||
| py-arch.c | ||
| py-auto-load.c | ||
| py-block.c | ||
| py-bpevent.c | ||
| py-breakpoint.c | ||
| py-cmd.c | ||
| py-color.c | ||
| py-color.h | ||
| py-connection.c | ||
| py-continueevent.c | ||
| py-dap.c | ||
| py-disasm.c | ||
| py-event-types.def | ||
| py-event.c | ||
| py-event.h | ||
| py-events.h | ||
| py-evtregistry.c | ||
| py-evts.c | ||
| py-exitedevent.c | ||
| py-finishbreakpoint.c | ||
| py-frame.c | ||
| py-framefilter.c | ||
| py-function.c | ||
| py-gdb-readline.c | ||
| py-inferior.c | ||
| py-infevents.c | ||
| py-infthread.c | ||
| py-instruction.c | ||
| py-instruction.h | ||
| py-lazy-string.c | ||
| py-linetable.c | ||
| py-membuf.c | ||
| py-mi.c | ||
| py-micmd.c | ||
| py-newobjfileevent.c | ||
| py-objfile.c | ||
| py-param.c | ||
| py-prettyprint.c | ||
| py-progspace.c | ||
| py-record-btrace.c | ||
| py-record-btrace.h | ||
| py-record-full.c | ||
| py-record-full.h | ||
| py-record.c | ||
| py-record.h | ||
| py-ref.h | ||
| py-registers.c | ||
| py-signalevent.c | ||
| py-stopevent.c | ||
| py-stopevent.h | ||
| py-symbol.c | ||
| py-symtab.c | ||
| py-threadevent.c | ||
| py-tui.c | ||
| py-type.c | ||
| py-uiout.h | ||
| py-unwind.c | ||
| py-utils.c | ||
| py-value.c | ||
| py-varobj.c | ||
| py-xmethods.c | ||
| python-config.py | ||
| python-internal.h | ||
| python.c | ||
| python.h | ||