MFC r304812:

In both do_rw_wrlock() and do_rw_rdlock(), do not obliterate possible
error from sleep.

1 files changed, 12 insertions, 6 deletions

diff --git a/sys/kern/kern_umtx.c b/sys/kern/kern_umtx.c
index f871d41..7a621fb 100644
--- a/sys/kern/kern_umtx.c
+++ b/sys/kern/kern_umtx.c
@@ -2831,7 +2831,7 @@ do_rw_rdlock(struct thread *td, struct urwlock *rwlock, long fflag, struct _umtx
 	uint32_t flags, wrflags;
 	int32_t state, oldstate;
 	int32_t blocked_readers;
-	int error, rv;
+	int error, error1, rv;
 
 	uq = td->td_umtxq;
 	error = fueword32(&rwlock->rw_flags, &flags);
@@ -2980,9 +2980,12 @@ sleep:
 				if (oldstate == state)
 					break;
 				state = oldstate;
-				error = umtxq_check_susp(td);
-				if (error != 0)
+				error1 = umtxq_check_susp(td);
+				if (error1 != 0) {
+					if (error == 0)
+						error = error1;
 					break;
+				}
 			}
 		}
 
@@ -3005,7 +3008,7 @@ do_rw_wrlock(struct thread *td, struct urwlock *rwlock, struct _umtx_time *timeo
 	int32_t state, oldstate;
 	int32_t blocked_writers;
 	int32_t blocked_readers;
-	int error, rv;
+	int error, error1, rv;
 
 	uq = td->td_umtxq;
 	error = fueword32(&rwlock->rw_flags, &flags);
@@ -3151,14 +3154,17 @@ sleep:
 				if (oldstate == state)
 					break;
 				state = oldstate;
-				error = umtxq_check_susp(td);
+				error1 = umtxq_check_susp(td);
 				/*
 				 * We are leaving the URWLOCK_WRITE_WAITERS
 				 * behind, but this should not harm the
 				 * correctness.
 				 */
-				if (error != 0)
+				if (error1 != 0) {
+					if (error == 0)
+						error = error1;
 					break;
+				}
 			}
 			rv = fueword32(&rwlock->rw_blocked_readers,
 			    &blocked_readers);