svn commit: r327402 - head/sys/kern

[Mateusz Guzik]

Author: mjg
Date: Sun Dec 31 02:31:01 2017
New Revision: 327402
URL: https://svnweb.freebsd.org/changeset/base/327402

Log:
  locks: adjust loop limit check when waiting for readers
  
  The check was for the exact value, but since the counter started being
  incremented by the number of readers it could have jumped over.

Modified:
  head/sys/kern/kern_rwlock.c
  head/sys/kern/kern_sx.c

Modified: head/sys/kern/kern_rwlock.c
==============================================================================
--- head/sys/kern/kern_rwlock.c	Sun Dec 31 01:59:56 2017	(r327401)
+++ head/sys/kern/kern_rwlock.c	Sun Dec 31 02:31:01 2017	(r327402)
@@ -516,7 +516,7 @@ __rw_rlock_hard(struct rwlock *rw, struct thread *td, 
 #endif
 			KTR_STATE0(KTR_SCHED, "thread", sched_tdname(curthread),
 			    "running");
-			if (i != rowner_loops)
+			if (i < rowner_loops)
 				continue;
 		}
 #endif
@@ -995,7 +995,7 @@ __rw_wlock_hard(volatile uintptr_t *c, uintptr_t v LOC
 #ifdef KDTRACE_HOOKS
 			lda.spin_cnt += rowner_loops - i;
 #endif
-			if (i != rowner_loops)
+			if (i < rowner_loops)
 				continue;
 			sleep_reason = 2;
 		}

Modified: head/sys/kern/kern_sx.c
==============================================================================
--- head/sys/kern/kern_sx.c	Sun Dec 31 01:59:56 2017	(r327401)
+++ head/sys/kern/kern_sx.c	Sun Dec 31 02:31:01 2017	(r327402)
@@ -671,7 +671,7 @@ _sx_xlock_hard(struct sx *sx, uintptr_t x, int opts LO
 #endif
 			KTR_STATE0(KTR_SCHED, "thread",
 			    sched_tdname(curthread), "running");
-			if (i != asx_loops)
+			if (i < asx_loops)
 				continue;
 			sleep_reason = 2;
 		}