This is a note to let you know that I've just added the patch titled bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent to the 6.1-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: bcache-fix-__bch_btree_node_alloc-to-make-the-failure-behavior-consistent.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 80fca8a10b604afad6c14213fdfd816c4eda3ee4 Mon Sep 17 00:00:00 2001 From: Zheng Wang <zyytlz.wz@xxxxxxx> Date: Thu, 15 Jun 2023 20:12:22 +0800 Subject: bcache: Fix __bch_btree_node_alloc to make the failure behavior consistent From: Zheng Wang <zyytlz.wz@xxxxxxx> commit 80fca8a10b604afad6c14213fdfd816c4eda3ee4 upstream. In some specific situations, the return value of __bch_btree_node_alloc may be NULL. This may lead to a potential NULL pointer dereference in caller function like a calling chain : btree_split->bch_btree_node_alloc->__bch_btree_node_alloc. Fix it by initializing the return value in __bch_btree_node_alloc. Fixes: cafe56359144 ("bcache: A block layer cache") Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Zheng Wang <zyytlz.wz@xxxxxxx> Signed-off-by: Coly Li <colyli@xxxxxxx> Link: https://lore.kernel.org/r/20230615121223.22502-6-colyli@xxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/md/bcache/btree.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/md/bcache/btree.c +++ b/drivers/md/bcache/btree.c @@ -1090,10 +1090,12 @@ struct btree *__bch_btree_node_alloc(str struct btree *parent) { BKEY_PADDED(key) k; - struct btree *b = ERR_PTR(-EAGAIN); + struct btree *b; mutex_lock(&c->bucket_lock); retry: + /* return ERR_PTR(-EAGAIN) when it fails */ + b = ERR_PTR(-EAGAIN); if (__bch_bucket_alloc_set(c, RESERVE_BTREE, &k.key, wait)) goto err; Patches currently in stable-queue which might be from zyytlz.wz@xxxxxxx are queue-6.1/bcache-fix-__bch_btree_node_alloc-to-make-the-failure-behavior-consistent.patch queue-6.1/bcache-remove-unnecessary-null-point-check-in-node-allocations.patch