Searched hist:197445 (Results 1 - 2 of 2) sorted by relevance
| /freebsd-11-stable/lib/libthr/thread/ | ||
| H A D | thr_umtx.h | diff 197445 Wed Sep 23 19:46:30 MDT 2009 attilio rwlock implemented from libthr need to fall through the 'hard path' and query umtx also if the shared waiters bit is set on a shared lock. The writer starvation avoidance technique, infact, can lead to shared waiters on a shared lock which can bring to a missed wakeup and thus to a deadlock if the right bit is not checked (a notable case is the writers counterpart to be handled through expired timeouts). Fix that by checking for the shared waiters bit also when unlocking the shared locks. That bug was causing a reported MySQL deadlock. Many thanks go to Nick Esborn and his employer DesertNet which provided time and machines to identify and fix this issue. PR: thread/135673 Reported by: Nick Esborn <nick at desert dot net> Tested by: Nick Esborn <nick at desert dot net> Reviewed by: jeff |
| /freebsd-11-stable/sys/kern/ | ||
| H A D | kern_umtx.c | diff 197476 Thu Sep 24 22:07:47 MDT 2009 davidxu In function do_rw_wrlock, when a writer got an error and before returning, check if there are readers blocked by us via URWLOCK_WRITE_WAITERS flag, and resume the readers. The error must be EAGAIN, otherwise there must have memory problem, and nobody can rescue the buggy application. The revision 197445 might be reverted. |
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