linux-kernel - Re: fs/gfs2/rgrp.c:1772:53: warning: Possible null pointer dereference: minext [nullPointer]

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Date:   Fri,  2 Apr 2021 20:03:45 +0200
From:   Andreas Gruenbacher <agruenba@...hat.com>
To:     cluster-devel@...hat.com
Cc:     Andreas Gruenbacher <agruenba@...hat.com>, kbuild-all@...ts.01.org,
        linux-kernel@...r.kernel.org, kernel test robot <lkp@...el.com>
Subject: Re: fs/gfs2/rgrp.c:1772:53: warning: Possible null pointer dereference: minext [nullPointer]

gfs2: Silence possible null pointer dereference warning

In gfs2_rbm_find, rs is always NULL when minext is NULL, so
gfs2_reservation_check_and_update will never be called on a NULL minext.
This isn't immediately obvious though, so also check for a NULL minext
for better code readability.

Reported-by: kernel test robot <lkp@...el.com>
Signed-off-by: Andreas Gruenbacher <agruenba@...hat.com>
---
 fs/gfs2/rgrp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 89c37a845e64..2dab313442a7 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1783,7 +1783,7 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 			goto next_bitmap;
 		}
 		rbm->offset = offset;
-		if (!rs)
+		if (!rs || !minext)
 			return 0;
 
 		ret = gfs2_reservation_check_and_update(rbm, rs, *minext,
-- 
2.27.0