On 2/19/19 8:02 AM, Jan Kara wrote:
On Tue 19-02-19 11:44:03, Colin King wrote:
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
There is a null check on the pointer bh to avoid a null pointer dereference
on bh->b_data however later bh is passed to mark_buffer_dirty that can also
cause a null pointer dereference on bh. Avoid this potential null pointer
dereference by moving the call to mark_buffer_dirty inside the null checked
block.
Fixes: e8b4274735e4 ("udf: finalize integrity descriptor before writeback")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Thanks for the patch! In fact it is the 'if (bh)' check that's
unnecessarily defensive (we cannot have sbi->s_lvid_dirty and
!sbi->s_lvid_bh). So I'll just drop that check (attached patch).
Honza
---
fs/udf/super.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/fs/udf/super.c b/fs/udf/super.c
index a6940d90bedd..b7e9a83d39db 100644
--- a/fs/udf/super.c
+++ b/fs/udf/super.c
@@ -2336,13 +2336,13 @@ static int udf_sync_fs(struct super_block *sb, int wait)
lvid = (struct logicalVolIntegrityDesc *)bh->b_data;
udf_finalize_lvid(lvid);
- }
- /*
- * Blockdevice will be synced later so we don't have to submit
- * the buffer for IO
- */
- mark_buffer_dirty(bh);
+ /*
+ * Blockdevice will be synced later so we don't have
+ * to submit the buffer for IO
+ */
+ mark_buffer_dirty(bh);
+ }
sbi->s_lvid_dirty = 0;
}
mutex_unlock(&sbi->s_alloc_mutex);
--
2.20.1
Reviewed-by: Steven J. Magnani <steve@xxxxxxxxxxxxxxx>
Doh! Thanks for the catch Colin.
------------------------------------------------------------------------
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www.digidescorp.com Earthling, return my space modulator!"
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