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Subject[PATCH] fs: affs: fix a NULL pointer dereference
Date
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 | 10 +++++++---
1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/fs/affs/file.c b/fs/affs/file.c
index a85817f54483..45b96faa40f1 100644
--- a/fs/affs/file.c
+++ b/fs/affs/file.c
@@ -835,7 +835,7 @@ void
affs_truncate(struct inode *inode)
{
struct super_block *sb = inode->i_sb;
- u32 ext, ext_key;
+ u32 ext, ext_key, ext_bk;
u32 last_blk, blkcnt, blk;
u32 size;
struct buffer_head *ext_bh;
@@ -941,8 +941,12 @@ 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++) {
+ ext_bk = AFFS_BLOCK(sb, ext_bh, i);
+ affs_free_block(sb, be32_to_cpu(ext_bk));
+ }
+ }
affs_free_block(sb, ext_key);
ext_key = be32_to_cpu(AFFS_TAIL(sb, ext_bh)->extension);
affs_brelse(ext_bh);
--
2.17.1
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