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05 April 2024, 19:05:47 UTC
Revision 5211613978cb7353a3237e4372958c0e7514683f authored by Oleg Nesterov on 22 October 2015, 20:32:08 UTC, committed by Linus Torvalds on 23 October 2015, 08:55:10 UTC 
kmod: don't run async usermode helper as a child of kworker thread
 
call_usermodehelper_exec_sync() does fork() + wait() with "unignored"
SIGCHLD.  What we have missed is that this worker thread can have other
children previously forked by call_usermodehelper_exec_work() without
UMH_WAIT_PROC.  If such a child exits in between it becomes a zombie
because auto-reaping only works if SIGCHLD is ignored, and nobody can
reap it (unless/until this worker thread exits too).

Change the !UMH_WAIT_PROC case to use CLONE_PARENT.

Note: this is only first step.  All PF_KTHREAD tasks, even created by
kernel_thread() should have ->parent == kthreadd by default.

Fixes: bb304a5c6fc63d8506c ("kmod: handle UMH_WAIT_PROC from system unbound workqueue")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 8a70dd2
History
Tip revision: 5211613978cb7353a3237e4372958c0e7514683f authored by Oleg Nesterov on 22 October 2015, 20:32:08 UTC
kmod: don't run async usermode helper as a child of kworker thread
Tip revision: 5211613
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.get_maintainer.ignore -rw-r--r-- 31 bytes
.gitignore -rw-r--r-- 1.2 KB
.mailmap -rw-r--r-- 5.3 KB
COPYING -rw-r--r-- 18.3 KB
CREDITS -rw-r--r-- 94.9 KB
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Kconfig -rw-r--r-- 252 bytes
MAINTAINERS -rw-r--r-- 320.4 KB
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