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From: Kangjie Lu <kjlu@umn.edu>
To: kjlu@umn.edu
Cc: pakki001@umn.edu, David Sterba <dsterba@suse.com>,
	linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] fs: affs: fix a NULL pointer dereference
Date: Fri, 15 Mar 2019 02:42:44 -0500	[thread overview]
Message-ID: <20190315074246.26426-1-kjlu@umn.edu> (raw)

If affs_bread fails, do not use ext_bh to avoid NULL pointer
 dereference

Signed-off-by: Kangjie Lu <kjlu@umn.edu>
---
 fs/affs/file.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/fs/affs/file.c b/fs/affs/file.c
index a85817f54483..29cbc8eda085 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -941,8 +941,10 @@ affs_truncate(struct inode *inode)
 		size = AFFS_SB(sb)->s_hashsize;
 		if (size > blkcnt - blk)
 			size = blkcnt - blk;
-		for (i = 0; i < size; i++, blk++)
-			affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
+		if (ext_bh) {
+			for (i = 0; i < size; i++, blk++)
+				affs_free_block(sb, be32_to_cpu(AFFS_BLOCK(sb, ext_bh, i)));
+		}
 		affs_free_block(sb, ext_key);
 		ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
 		affs_brelse(ext_bh);
-- 
2.17.1


             reply	other threads:[~2019-03-15  7:43 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-15  7:42 Kangjie Lu [this message]
2019-03-21 14:45 ` [PATCH] fs: affs: fix a NULL pointer dereference David Sterba
  -- strict thread matches above, loose matches on Subject: below --
2019-03-14  7:46 Kangjie Lu
2019-03-14 14:51 ` kbuild test robot
2019-03-19  9:00 ` Dan Carpenter
2019-03-19 13:43 ` Geert Uytterhoeven

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