| Message ID | 20131204072926.GK10323@ZenIV.linux.org.uk |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Wed, Dec 04, 2013 at 07:29:26AM +0000, Al Viro wrote: > That thing should be del_timer_sync(); consider what happens > if ext4_put_super() call of del_timer() happens to come just as it's > getting run on another CPU. Since that timer reschedules itself > to run next day, you are pretty much guaranteed that you'll end up > with kfree'd scheduled timer, with usual fun consequences. AFAICS, > that's -stable fodder all way back to 2010... [the second del_timer_sync() > is almost certainly not needed, but it doesn't hurt either] > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Nice catch. Thanks, applied. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/ext4/super.c b/fs/ext4/super.c index c977f4e..9d70c0c 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -792,7 +792,7 @@ static void ext4_put_super(struct super_block *sb) } ext4_es_unregister_shrinker(sbi); - del_timer(&sbi->s_err_report); + del_timer_sync(&sbi->s_err_report); ext4_release_system_zone(sb); ext4_mb_release(sb); ext4_ext_release(sb); @@ -4184,7 +4184,7 @@ failed_mount_wq: } failed_mount3: ext4_es_unregister_shrinker(sbi); - del_timer(&sbi->s_err_report); + del_timer_sync(&sbi->s_err_report); if (sbi->s_flex_groups) ext4_kvfree(sbi->s_flex_groups); percpu_counter_destroy(&sbi->s_freeclusters_counter);
That thing should be del_timer_sync(); consider what happens if ext4_put_super() call of del_timer() happens to come just as it's getting run on another CPU. Since that timer reschedules itself to run next day, you are pretty much guaranteed that you'll end up with kfree'd scheduled timer, with usual fun consequences. AFAICS, that's -stable fodder all way back to 2010... [the second del_timer_sync() is almost certainly not needed, but it doesn't hurt either] Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> --- -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html