From 97f53c43785e59cc7257877fb35da2d867b00ae3 Mon Sep 17 00:00:00 2001 From: Pankaj Gupta Date: Tue, 30 Jul 2019 17:07:08 +0530 Subject: [PATCH] dm table: fix dax_dev NULL dereference in device_synchronous() If a device doesn't support DAX its 'dax_dev' is NULL. Fix device_synchronous() to first check if dax_dev is NULL before dereferencing it. Fixes: b5880cce7629 ("dm: enable synchronous dax") Reported-by: jencce.kernel@gmail.com Signed-off-by: Pankaj Gupta Acked-by: Dan Williams Signed-off-by: Mike Snitzer --- drivers/md/dm-table.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index caaee8032afef..12857beaa7f90 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -894,7 +894,7 @@ int device_supports_dax(struct dm_target *ti, struct dm_dev *dev, static int device_synchronous(struct dm_target *ti, struct dm_dev *dev, sector_t start, sector_t len, void *data) { - return dax_synchronous(dev->dax_dev); + return dev->dax_dev && dax_synchronous(dev->dax_dev); } bool dm_table_supports_dax(struct dm_table *t, -- 2.39.5