From 018e32c194500f646f74fee2263de320553fa771 Mon Sep 17 00:00:00 2001 From: Colin Percival Date: Wed, 17 Mar 2004 09:37:13 +0000 Subject: Adjust the number of processes waiting on a semaphore properly if we're woken up in the middle of sleeping. PR: misc/64347 Reviewed by: tjr MFC after: 7 days --- sys/kern/sysv_sem.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'sys/kern') diff --git a/sys/kern/sysv_sem.c b/sys/kern/sysv_sem.c index e07e632d8af4..1cd6e1bb0eac 100644 --- a/sys/kern/sysv_sem.c +++ b/sys/kern/sysv_sem.c @@ -1040,12 +1040,7 @@ semop(td, uap) error = msleep(semaptr, sema_mtxp, (PZERO - 4) | PCATCH, "semwait", 0); DPRINTF(("semop: good morning (error=%d)!\n", error)); - - if (error != 0) { - error = EINTR; - goto done2; - } - DPRINTF(("semop: good morning!\n")); + /* return code is checked below, after sem[nz]cnt-- */ /* * Make sure that the semaphore still exists @@ -1064,6 +1059,17 @@ semop(td, uap) semptr->semzcnt--; else semptr->semncnt--; + + /* + * Is it really morning, or was our sleep interrupted? + * (Delayed check of msleep() return code because we + * need to decrement sem[nz]cnt either way.) + */ + if (error != 0) { + error = EINTR; + goto done2; + } + DPRINTF(("semop: good morning!\n")); } done: -- cgit v1.3