ocfs2: don't put and assigning null to bh allocated outside
authorChangwei Ge <ge.changwei@h3c.com>
Fri, 2 Nov 2018 22:48:19 +0000 (15:48 -0700)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 28 Nov 2019 17:28:53 +0000 (18:28 +0100)
commit65cbd1279f4b999d56a838344a30642db24cd215
treeb548b88c4596744f5bfca7a9883b6224e189244f
parentb2c50f6fcb26d35cdbe48d42a216101df448c49e
ocfs2: don't put and assigning null to bh allocated outside

[ Upstream commit cf76c78595ca87548ca5e45c862ac9e0949c4687 ]

ocfs2_read_blocks() and ocfs2_read_blocks_sync() are both used to read
several blocks from disk.  Currently, the input argument *bhs* can be
NULL or NOT.  It depends on the caller's behavior.  If the function
fails in reading blocks from disk, the corresponding bh will be assigned
to NULL and put.

Obviously, above process for non-NULL input bh is not appropriate.
Because the caller doesn't even know its bhs are put and re-assigned.

If buffer head is managed by caller, ocfs2_read_blocks and
ocfs2_read_blocks_sync() should not evaluate it to NULL.  It will cause
caller accessing illegal memory, thus crash.

Link: http://lkml.kernel.org/r/HK2PR06MB045285E0F4FBB561F9F2F9B3D5680@HK2PR06MB0452.apcprd06.prod.outlook.com
Signed-off-by: Changwei Ge <ge.changwei@h3c.com>
Reviewed-by: Guozhonghua <guozhonghua@h3c.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <jiangqi903@gmail.com>
Cc: Changwei Ge <ge.changwei@h3c.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
fs/ocfs2/buffer_head_io.c