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If two threads are calling setxid simultanously a race exists between releasing setxid_futex in sighandler_setxid and locking it again in setxid_mark_thread when the thread exited in the mean time. Make sure the exiting thread is eventually woken up. Andreas. 2010-06-28 Andreas Schwab <schwab@redhat.com> * allocatestack.c (setxid_mark_thread): Ensure that the exiting thread is woken up. diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c index 831e98e..1ce9ed5 100644 --- a/nptl/allocatestack.c +++ b/nptl/allocatestack.c @@ -994,7 +994,16 @@ setxid_mark_thread (struct xid_command *cmdp, struct pthread *t) /* If the thread is exiting right now, ignore it. */ if ((ch & EXITING_BITMASK) != 0) - return; + { + /* Release the futex if there is no other setxid in + progress. */ + if ((ch & SETXID_BITMASK) == 0) + { + t->setxid_futex = 1; + lll_futex_wake (&t->setxid_futex, 1, LLL_PRIVATE); + } + return; + } } while (atomic_compare_and_exchange_bool_acq (&t->cancelhandling, ch | SETXID_BITMASK, ch)); -- 1.7.1 -- Andreas Schwab, schwab@redhat.com GPG Key fingerprint = D4E8 DBE3 3813 BB5D FA84 5EC7 45C6 250E 6F00 984E "And now for something completely different."
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