summaryrefslogtreecommitdiff
path: root/fs/ext4
diff options
context:
space:
mode:
authorRitesh Harjani <riteshh@linux.ibm.com>2020-03-18 09:13:01 +0300
committerTheodore Ts'o <tytso@mit.edu>2020-03-26 17:52:49 +0300
commit5e47868fb94b63c7068dcfd2469d99fba06bae9d (patch)
treed4fb41eae543918573f41d67885cef56f83e6b34 /fs/ext4
parentf1eec3b0d0a849996ebee733b053efa71803dad5 (diff)
downloadlinux-5e47868fb94b63c7068dcfd2469d99fba06bae9d.tar.xz
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')
-rw-r--r--fs/ext4/super.c8
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);