3.11.10.4 -stable review patch.  If anyone has any objections, please let me 
know.

------------------

From: Minchan Kim <[email protected]>

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 <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Cc: Nitin Gupta <[email protected]>
Cc: Jerome Marchand <[email protected]>
Tested-by: Sergey Senozhatsky <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
[ luis: backported to 3.11: zram is still a staging driver in 3.11 ]
Signed-off-by: Luis Henriques <[email protected]>
---
 drivers/staging/zram/zram_drv.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/zram/zram_drv.c b/drivers/staging/zram/zram_drv.c
index dda8771..fc540ea 100644
--- a/drivers/staging/zram/zram_drv.c
+++ b/drivers/staging/zram/zram_drv.c
@@ -551,14 +551,14 @@ 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;
 
-- 
1.8.3.2

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