| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 094/133] zram: fix race between reset and flushing pending work | Date | Tue, 4 Feb 2014 13:08:15 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Minchan Kim <minchan@kernel.org>
commit da4a04126baa3be03bc566d4a2ee0944c5e783d0 upstream.
Dan and Sergey reported that there is a racy between reset and flushing of pending work so that it could make oops by freeing zram->meta in reset while zram_slot_free can access zram->meta if new request is adding during the race window.
This patch moves flush after taking init_lock so it prevents new request so that it closes the race.
Signed-off-by: Minchan Kim <minchan@kernel.org> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Jerome Marchand <jmarchan@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- drivers/staging/zram/zram_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -552,14 +552,14 @@ static void zram_reset_device(struct zra size_t index; struct zram_meta *meta; - flush_work(&zram->free_work); - down_write(&zram->init_lock); if (!zram->init_done) { up_write(&zram->init_lock); return; } + flush_work(&zram->free_work); + meta = zram->meta; zram->init_done = 0;
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