| From foo@baz Sun Aug 26 09:13:00 CEST 2018 |
| From: Davidlohr Bueso <dave@stgolabs.net> |
| Date: Thu, 26 Jul 2018 16:37:19 -0700 |
| Subject: ipc/sem.c: prevent queue.status tearing in semop |
| |
| From: Davidlohr Bueso <dave@stgolabs.net> |
| |
| [ Upstream commit f075faa300acc4f6301e348acde0a4580ed5f77c ] |
| |
| In order for load/store tearing prevention to work, _all_ accesses to |
| the variable in question need to be done around READ and WRITE_ONCE() |
| macros. Ensure everyone does so for q->status variable for |
| semtimedop(). |
| |
| Link: http://lkml.kernel.org/r/20180717052654.676-1-dave@stgolabs.net |
| Signed-off-by: Davidlohr Bueso <dbueso@suse.de> |
| Cc: Manfred Spraul <manfred@colorfullife.com> |
| Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
| Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
| Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| ipc/sem.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- a/ipc/sem.c |
| +++ b/ipc/sem.c |
| @@ -2041,7 +2041,7 @@ static long do_semtimedop(int semid, str |
| } |
| |
| do { |
| - queue.status = -EINTR; |
| + WRITE_ONCE(queue.status, -EINTR); |
| queue.sleeper = current; |
| |
| __set_current_state(TASK_INTERRUPTIBLE); |
