Module Name: src
Committed By: thorpej
Date: Thu Aug 5 23:23:50 UTC 2021
Modified Files:
src/sys/kern [thorpej-futex2]: sys_futex.c
Log Message:
At the end of futex_wait(), when sleepq_block() returns 0, we would like
to assert that l->l_futex == NULL, because all of the code paths that awaken
a blocked thread in sys_futex.c itself clear l->l_futex. Unfortunately,
there are certain received-a-signal situations (e.g. SIGKILL) where
sleepq_block() will not return an error after being awakened by the signal,
rendering this assertion too strong.
So, rather than going down the rabbit hole of reasoning out and altering
long-standing behavior of the signals code, just don't assert there and
treat a zero-return from sleepq_block() as an aborted futex wait if
l->l_futex != NULL.
(Thanks chs@ for helping chase this one down.)
To generate a diff of this commit:
cvs rdiff -u -r1.12.4.1 -r1.12.4.2 src/sys/kern/sys_futex.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
