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Code Issues Projects Releases Packages Wiki Activity Actions 11

bpo-44434: Don't call PyThread_exit_thread() explicitly (GH-26758) (GH-26824)

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_thread.start_new_thread() no longer calls PyThread_exit_thread()
explicitly at the thread exit, the call was redundant.

On Linux with the glibc, pthread_cancel() loads dynamically the
libgcc_s.so.1 library. dlopen() can fail if there is no more
available file descriptor to open the file. In this case, the process
aborts with the error message:

"libgcc_s.so.1 must be installed for pthread_cancel to work"

pthread_cancel() unwinds back to the thread's wrapping function that
calls the thread entry point.

The unwind function is dynamically loaded from the libgcc_s library
since it is tightly coupled to the C compiler (GCC). The unwinder
depends on DWARF, the compiler generates DWARF, so the unwinder
belongs to the compiler.

Thanks Florian Weimer and Carlos O'Donell for their help on
investigating this issue.
(cherry picked from commit 45a78f906d)

Co-authored-by: Victor Stinner <vstinner@python.org>
This commit is contained in:
Miss Islington (bot) 2021-06-21 05:29:17 -07:00 • committed by GitHub
parent 9b0bbb9143
commit 6614eac843
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2 changed files with 7 additions and 1 deletions
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4
Modules/_threadmodule.c
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@ -1105,7 +1105,9 @@ thread_run(void *boot_raw)
PyThreadState_Clear(tstate);
_PyThreadState_DeleteCurrent(tstate);
PyThread_exit_thread();
// bpo-44434: Don't call explicitly PyThread_exit_thread(). On Linux with
// the glibc, pthread_exit() can abort the whole process if dlopen() fails
// to open the libgcc_s.so library (ex: EMFILE error).
}
static PyObject *