diff options
| author | Ritesh Harjani <riteshh@linux.ibm.com> | 2020-03-18 11:43:01 +0530 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-03-26 10:52:49 -0400 |
| commit | 5e47868fb94b63c7068dcfd2469d99fba06bae9d (patch) | |
| tree | d4fb41eae543918573f41d67885cef56f83e6b34 /fs/ext4/super.c | |
| parent | f1eec3b0d0a849996ebee733b053efa71803dad5 (diff) | |
ext4: unregister sysfs path before destroying jbd2 journal
Call ext4_unregister_sysfs(), before destroying jbd2 journal,
since below might cause, NULL pointer dereference issue.
This got reported with LTP tests.
ext4_put_super() cat /sys/fs/ext4/loop2/journal_task
| ext4_attr_show();
ext4_jbd2_journal_destroy(); |
| journal_task_show()
| |
| task_pid_vnr(NULL);
sbi->s_journal = NULL;
Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20200318061301.4320-1-riteshh@linux.ibm.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/super.c')
| -rw-r--r-- | fs/ext4/super.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 5dc65b7583cb..27ab130a40d1 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1024,6 +1024,13 @@ static void ext4_put_super(struct super_block *sb) destroy_workqueue(sbi->rsv_conversion_wq); + /* + * Unregister sysfs before destroying jbd2 journal. + * Since we could still access attr_journal_task attribute via sysfs + * path which could have sbi->s_journal->j_task as NULL + */ + ext4_unregister_sysfs(sb); + if (sbi->s_journal) { aborted = is_journal_aborted(sbi->s_journal); err = jbd2_journal_destroy(sbi->s_journal); @@ -1034,7 +1041,6 @@ static void ext4_put_super(struct super_block *sb) } } - ext4_unregister_sysfs(sb); ext4_es_unregister_shrinker(sbi); del_timer_sync(&sbi->s_err_report); ext4_release_system_zone(sb); |