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To:     rpeterso@redhat.com, agruenba@redhat.com
Cc:     cluster-devel@redhat.com, linux-kernel@vger.kernel.org
From:   Jia-Ju Bai <baijiaju1990@gmail.com>
Subject: [BUG] fs: gfs2: possible null-pointer dereferences in
 gfs2_rgrp_bh_get()
Message-ID: <8d270882-54da-365e-1be7-a291a5178b1e@gmail.com>
Date:   Wed, 24 Jul 2019 16:50:03 +0800
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In gfs2_rgrp_bh_get, there is an if statement on line 1191 to check 
whether "rgd->rd_bits[0].bi_bh" is NULL.
When "rgd->rd_bits[0].bi_bh" is NULL, it is used on line 1216:
     gfs2_rgrp_in(rgd, (rgd->rd_bits[0].bi_bh)->b_data);
and on line 1225:
     gfs2_rgrp_ondisk2lvb(..., rgd->rd_bits[0].bi_bh->b_data);
and on line 1228:
     if (!gfs2_rgrp_lvb_valid(rgd))

Note that in gfs2_rgrp_lvb_valid(rgd), there is a statement on line 1114:
     struct gfs2_rgrp *str = (struct gfs2_rgrp 
*)rgd->rd_bits[0].bi_bh->b_data;

Thus, possible null-pointer dereferences may occur.

These bugs are found by a static analysis tool STCheck written by us.
I do not know how to correctly fix these bugs, so I only report bugs.


Best wishes,
Jia-Ju Bai