[3.6] bpo-32777: Fix _Py_set_inheritable async-safety in subprocess (GH-5560) #5563
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…GH-5560) Fix a rare but potential pre-exec child process deadlock in subprocess on POSIX systems when marking file descriptors inheritable on exec in the child process. This bug appears to have been introduced in 3.4 with the inheritable file descriptors support. This also changes Python/fileutils.c `set_inheritable` to use the "slow" two `fcntl` syscall path instead of the "fast" single `ioctl` syscall path when asked to be async signal safe (by way of being asked not to raise exceptions). `ioctl` is not a POSIX async-signal-safe approved function. ref: http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html (cherry picked from commit c1e46e9) Co-authored-by: Alexey Izbyshev <izbyshev@users.noreply.github.com>
gpshead
approved these changes
Feb 6, 2018
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Thanks, @gpshead! |
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Fix a rare but potential pre-exec child process deadlock in subprocess on POSIX systems when marking file descriptors inheritable on exec in the child process. This bug appears to have been introduced in 3.4 with the inheritable file descriptors support.
This also changes Python/fileutils.c
set_inheritableto use the "slow" twofcntlsyscall path instead of the "fast" singleioctlsyscall path when asked to be async signal safe (by way of being asked not to raise exceptions).ioctlis not a POSIX async-signal-safe approved function.ref: http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html
(cherry picked from commit c1e46e9)
Co-authored-by: Alexey Izbyshev izbyshev@users.noreply.github.com
https://bugs.python.org/issue32777