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| author | Oleg Nesterov <oleg@tv-sign.ru> | 2006-08-21 08:34:15 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@suse.de> | 2006-08-21 08:34:15 +0200 |
| commit | 9f83e45eb54fc7198dc59fc63255341851ba4c48 (patch) | |
| tree | 3874581e08052b7f37f164110b3bd44ae5eff291 /block | |
| parent | 78bd4d484f81a611ef6ff02f909e576cb9aac7f2 (diff) | |
| download | lwn-9f83e45eb54fc7198dc59fc63255341851ba4c48.tar.gz lwn-9f83e45eb54fc7198dc59fc63255341851ba4c48.zip | |
[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>
Diffstat (limited to 'block')
| -rw-r--r-- | block/ll_rw_blk.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c index 61d6b3c65b66..ddd9253f9d55 100644 --- a/block/ll_rw_blk.c +++ b/block/ll_rw_blk.c @@ -3628,6 +3628,8 @@ struct io_context *current_io_context(gfp_t gfp_flags) ret->nr_batch_requests = 0; /* because this is 0 */ ret->aic = NULL; ret->cic_root.rb_node = NULL; + /* make sure set_task_ioprio() sees the settings above */ + smp_wmb(); tsk->io_context = ret; } |