Patch "xfs: fortify xfs_alloc_buftarg error handling" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

xfs: fortify xfs_alloc_buftarg error handling

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xfs-fortify-xfs_alloc_buftarg-error-handling.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Michal Hocko <[email protected]>
Date: Thu, 23 Nov 2017 17:13:40 +0100
Subject: xfs: fortify xfs_alloc_buftarg error handling

From: Michal Hocko <[email protected]>

[ Upstream commit d210a9874b8f6166579408131cb74495caff1958 ]

percpu_counter_init failure path doesn't clean up &btp->bt_lru list. Call list_lru_destroy in that error path. Similarly register_shrinker error path is not handled.

While it is unlikely to trigger these error path, it is not impossible especially the later might fail with large NUMAs. Let's handle the failure to make the code more robust.

---
 fs/xfs/xfs_buf.c |   15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

@@ -1813,22 +1813,27 @@ xfs_alloc_buftarg(
 	btp->bt_daxdev = dax_dev;
 
 	if (xfs_setsize_buftarg_early(btp, bdev))
-		goto error;
+		goto error_free;
 
 	if (list_lru_init(&btp->bt_lru))
-		goto error;
+		goto error_free;
 
 	if (percpu_counter_init(&btp->bt_io_count, 0, GFP_KERNEL))
-		goto error;
+		goto error_lru;
 
 	btp->bt_shrinker.count_objects = xfs_buftarg_shrink_count;
 	btp->bt_shrinker.scan_objects = xfs_buftarg_shrink_scan;
 	btp->bt_shrinker.seeks = DEFAULT_SEEKS;
 	btp->bt_shrinker.flags = SHRINKER_NUMA_AWARE;
-	register_shrinker(&btp->bt_shrinker);
+	if (register_shrinker(&btp->bt_shrinker))
+		goto error_pcpu;
 	return btp;
 
-error:
+error_pcpu:
+	percpu_counter_destroy(&btp->bt_io_count);
+error_lru:
+	list_lru_destroy(&btp->bt_lru);
+error_free:
 	kmem_free(btp);
 	return NULL;
 }

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/quota-check-for-register_shrinker-failure.patch queue-4.14/xfs-fortify-xfs_alloc_buftarg-error-handling.patch