From da4a04126baa3be03bc566d4a2ee0944c5e783d0 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Thu, 30 Jan 2014 15:45:58 -0800 Subject: [PATCH] zram: fix race between reset and flushing pending work 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 Reported-by: Dan Carpenter Cc: Nitin Gupta Cc: Jerome Marchand Tested-by: Sergey Senozhatsky Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/block/zram/zram_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index f9711c5..213dfc1 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -553,14 +553,14 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity) 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; -- 2.7.4