[PATCH] Fix current_io_context() vs set_task_ioprio() race

I know nothing about io scheduler, but I suspect set_task_ioprio() is not safe.

current_io_context() initializes "struct io_context", then sets ->io_context.
set_task_ioprio() running on another cpu may see the changes out of order, so
->set_ioprio(ioc) may use io_context which was not initialized properly.

Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Jens Axboe <axboe@suse.de>
This commit is contained in:
Oleg Nesterov
2006-08-21 08:34:15 +02:00
committed by Jens Axboe
parent 78bd4d484f
commit 9f83e45eb5
2 changed files with 5 additions and 0 deletions
+3
View File
@@ -44,6 +44,9 @@ static int set_task_ioprio(struct task_struct *task, int ioprio)
task->ioprio = ioprio;
ioc = task->io_context;
/* see wmb() in current_io_context() */
smp_read_barrier_depends();
if (ioc && ioc->set_ioprio)
ioc->set_ioprio(ioc, ioprio);