From: Jiufei Xue <jiufei.xue@linux.alibaba.com>
To: linux-ext4@vger.kernel.org
Cc: tytso@mit.edu, joseph.qi@linux.alibaba.com
Subject: [PATCH] ext4: fix NULL pointer dereference while journal is aborted
Date: Mon, 11 Mar 2019 14:35:28 +0800 [thread overview]
Message-ID: <20190311063528.112996-1-jiufei.xue@linux.alibaba.com> (raw)
We see the following NULL pointer dereference while running xfstests
generic/475:
BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
PGD 8000000c84bad067 P4D 8000000c84bad067 PUD c84e62067 PMD 0
Oops: 0000 [#1] SMP PTI
CPU: 7 PID: 9886 Comm: fsstress Kdump: loaded Not tainted 5.0.0-rc8 #10
RIP: 0010:ext4_do_update_inode+0x4ec/0x760
...
Call Trace:
? jbd2_journal_get_write_access+0x42/0x50
? __ext4_journal_get_write_access+0x2c/0x70
? ext4_truncate+0x186/0x3f0
ext4_mark_iloc_dirty+0x61/0x80
ext4_mark_inode_dirty+0x62/0x1b0
ext4_truncate+0x186/0x3f0
? unmap_mapping_pages+0x56/0x100
ext4_setattr+0x817/0x8b0
notify_change+0x1df/0x430
do_truncate+0x5e/0x90
? generic_permission+0x12b/0x1a0
This is triggered because the NULL pointer handle->h_transaction was
dereferenced in function ext4_update_inode_fsync_trans().
I found that the h_transaction was set to NULL in jbd2__journal_restart
but failed to attached to a new transaction while the journal is aborted.
Fix this by checking the handle before updating the inode.
Signed-off-by: Jiufei Xue <jiufei.xue@linux.alibaba.com>
---
fs/ext4/ext4_jbd2.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
index a1ac7e9245ec..75a5309f2231 100644
--- a/fs/ext4/ext4_jbd2.h
+++ b/fs/ext4/ext4_jbd2.h
@@ -384,7 +384,7 @@ static inline void ext4_update_inode_fsync_trans(handle_t *handle,
{
struct ext4_inode_info *ei = EXT4_I(inode);
- if (ext4_handle_valid(handle)) {
+ if (ext4_handle_valid(handle) && !is_handle_aborted(handle)) {
ei->i_sync_tid = handle->h_transaction->t_tid;
if (datasync)
ei->i_datasync_tid = handle->h_transaction->t_tid;
--
2.19.1.856.g8858448bb
next reply other threads:[~2019-03-11 6:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-11 6:35 Jiufei Xue [this message]
2019-03-11 6:45 ` [PATCH] ext4: fix NULL pointer dereference while journal is aborted Joseph Qi
2019-03-12 11:00 ` Jiufei Xue
2019-03-15 1:18 ` Jiufei Xue
2019-03-15 3:17 ` Theodore Ts'o
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