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Date: Fri, 13 Sep 2013 20:36:55 -0600 From: Chuck Coffing <clc@...m.mit.edu> To: linux-kernel@...r.kernel.org Cc: Alexander Viro <viro@...iv.linux.org.uk> Subject: [PATCH] bad bd_fsfreeze_count in freeze_bdev Hi, An error path in freeze_bdev screws up the freeze count. Consider: - call freeze_bdev with a bdev that's unmounted (stupidity or a race) - bd_fsfreeze_count is unconditionally incremented on entry - can't get the sb; error out - bd_fsfreeze_count is not decremented (oops!) - call freeze_bdev again just for obnoxiousness... - since bd_fsfreeze_count is already nonzero, sb is assumed good and deref'd (CC me, I'm not subscribed) diff --git a/fs/block_dev.c b/fs/block_dev.c index c3549ed..f1c5561 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -253,6 +253,7 @@ struct super_block *freeze_bdev(struct block_device *bdev) } deactivate_super(sb); out: + bdev->bd_fsfreeze_count--; sync_blockdev(bdev); mutex_unlock(&bdev->bd_fsfreeze_mutex); return sb; /* thaw_bdev releases s->s_umount */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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