libpthread-138.10.4.tar.gz

[apple/libpthread.git] / kern / kern_synch.c

diff --git a/kern/kern_synch.c b/kern/kern_synch.c
index 713691265dae1c17459d519ed9e31e9edcb54922..4e7674941a3530945e7a91fbf9c079c3d8172efb 100644 (file)
--- a/kern/kern_synch.c
+++ b/kern/kern_synch.c
@@ -468,8 +468,8 @@ _ksyn_handle_missed_wakeups(ksyn_wait_queue_t kwq,
 {
        int res = 0;
        if (kwq->kw_pre_intrcount != 0 &&
-           kwq->kw_pre_intrtype == type &&
-           is_seqlower_eq(lockseq, kwq->kw_pre_intrseq)) {
+               kwq->kw_pre_intrtype == type &&
+               (kwq->kw_pre_intrseq == 0 || is_seqlower_eq(lockseq, kwq->kw_pre_intrseq))) {
                kwq->kw_pre_intrcount--;
                *retval = kwq->kw_pre_intrretbits;
                if (kwq->kw_pre_intrcount == 0) {
@@ -1413,7 +1413,8 @@ _psynch_rw_unlock(__unused proc_t p,
        int diff;
        uint32_t count = 0;
        uint32_t curgen = lgenval & PTHRW_COUNT_MASK;
-       
+       int clearedkflags = 0;
+
        error = ksyn_wqfind(rwlock, lgenval, ugenval, rw_wc, flags, (KSYN_WQTYPE_INDROP | KSYN_WQTYPE_RWLOCK), &kwq);
        if (error != 0) {
                return(error);
@@ -1439,6 +1440,7 @@ _psynch_rw_unlock(__unused proc_t p,
        /* no prepost and all threads are in place, reset the bit */
        if ((isinit != 0) && ((kwq->kw_kflags & KSYN_KWF_INITCLEARED) != 0)){
                kwq->kw_kflags &= ~KSYN_KWF_INITCLEARED;
+               clearedkflags = 1;
        }
        
        /* can handle unlock now */
@@ -1455,7 +1457,14 @@ out:
                /* update bits?? */
                *retval = updatebits;
        }
-       
+
+       // <rdar://problem/22244050> If any of the wakeups failed because they already
+       // returned to userspace because of a signal then we need to ensure that the
+       // reset state is not cleared when that thread returns. Otherwise,
+       // _pthread_rwlock_lock will clear the interrupted state before it is read.
+       if (clearedkflags != 0 && kwq->kw_pre_intrcount > 0) {
+               kwq->kw_kflags |= KSYN_KWF_INITCLEARED;
+       }
        
        ksyn_wqunlock(kwq);
        ksyn_wqrelease(kwq, 0, (KSYN_WQTYPE_INDROP | KSYN_WQTYPE_RWLOCK));