diff options
| author | Scott Soule Cheloha <cheloha@cvs.openbsd.org> | 2023-09-09 03:03:46 +0000 |
|---|---|---|
| committer | Scott Soule Cheloha <cheloha@cvs.openbsd.org> | 2023-09-09 03:03:46 +0000 |
| commit | bfcd46b1eac2edf51f89b9518c80da4a47705925 (patch) | |
| tree | 5a15849992ec9ae5cfe37a1d560524f99c42260c /sys/kern | |
| parent | 921632a343f89d58fb8755b64c23f245f288b358 (diff) | |
clockintr_dispatch: copy cl_func to cq_shadow.cl_func before calling it
When we add support for disestablishing clockintrs in the near future,
the current call to cl->cl_func will be in a race with free(9) on
another CPU. Copying cl_func to cq_shadow.cl_func before leaving the
mutex and then calling the copy eliminates the race.
Correcting the race has a negligible performance impact and simplifies
the forthcoming clockintr_disestablish() patch.
Requested by dlg@ back in March.
Diffstat (limited to 'sys/kern')
| -rw-r--r-- | sys/kern/kern_clockintr.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/sys/kern/kern_clockintr.c b/sys/kern/kern_clockintr.c index d22ad2b9055..b91c7b6a483 100644 --- a/sys/kern/kern_clockintr.c +++ b/sys/kern/kern_clockintr.c @@ -1,4 +1,4 @@ -/* $OpenBSD: kern_clockintr.c,v 1.40 2023/09/08 22:23:30 cheloha Exp $ */ +/* $OpenBSD: kern_clockintr.c,v 1.41 2023/09/09 03:03:45 cheloha Exp $ */ /* * Copyright (c) 2003 Dale Rahn <drahn@openbsd.org> * Copyright (c) 2020 Mark Kettenis <kettenis@openbsd.org> @@ -258,10 +258,11 @@ clockintr_dispatch(void *frame) } clockqueue_pend_delete(cq, cl); cq->cq_shadow.cl_expiration = cl->cl_expiration; + cq->cq_shadow.cl_func = cl->cl_func; cq->cq_running = cl; mtx_leave(&cq->cq_mtx); - cl->cl_func(&cq->cq_shadow, frame); + cq->cq_shadow.cl_func(&cq->cq_shadow, frame); mtx_enter(&cq->cq_mtx); cq->cq_running = NULL; |