ext4: fix NULL pointer dereference in print_daily_error_info()

commit a1c6c5698d53db4c47a25c3a8d11731a4d7b8370 upstream.

Fix NULL pointer dereference in print_daily_error_info, when
called on unmounted fs (EXT4_SB(sb) returns NULL), by removing error
reporting timer in ext4_put_super.

Google-Bug-Id: 3017663

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Thomas Meyer <thomas@m3y3r.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 26147746c272c2112b7067aa6415800434586b50..751997d2cefe555803b61fb68d8c23aa867b3016 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -719,6 +719,7 @@ static void ext4_put_super(struct super_block *sb)
                        ext4_abort(sb, "Couldn't clean up the journal");
        }
 
+       del_timer(&sbi->s_err_report);
        ext4_release_system_zone(sb);
        ext4_mb_release(sb);
        ext4_ext_release(sb);