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authorMinchan Kim <minchan@kernel.org>2014-01-30 15:45:58 -0800
committerSimon Shields <keepcalm444@gmail.com>2016-06-12 21:19:53 +1000
commit5343c207e9f3941bc8fa156a884553832f49fb43 (patch)
tree3ee35a9804c370b20c90961d06ccc5693e3a6756
parent7bd9d3e31b18fa94c80849c567fd64359d90754b (diff)
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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 <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> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--drivers/block/zram/zram_drv.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 05c8258..7881508 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -564,14 +564,14 @@ 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;