This is a note to let you know that I've just added the patch titled net/sched: move NULL ptr check to qdisc_put() too to the 4.19-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: net-sched-move-null-ptr-check-to-qdisc_put-too.patch and it can be found in the queue-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From didi.debian@xxxxxxxxx Thu Jun 30 15:24:25 2022 From: Diederik de Haas <didi.debian@xxxxxxxxx> Date: Thu, 30 Jun 2022 00:49:38 +0200 Subject: net/sched: move NULL ptr check to qdisc_put() too To: stable@xxxxxxxxxxxxxxx Cc: Vlad Buslov <vladbu@xxxxxxxxxxxx>, Diederik de Haas <didi.debian@xxxxxxxxx>, Thorsten Glaser <tg@xxxxxxxxx> Message-ID: <20220629224938.7760-1-didi.debian@xxxxxxxxx> From: Diederik de Haas <didi.debian@xxxxxxxxx> In commit 92833e8b5db6c209e9311ac8c6a44d3bf1856659 titled "net: sched: rename qdisc_destroy() to qdisc_put()" part of the functionality of qdisc_destroy() was moved into a (for linux-4.19.y) new function qdisk_put(), and the previous calls to qdisc_destroy() were changed to qdisk_put(). This made it similar to f.e. 5.10.y and current master. There was one part of qdisc_destroy() not moved over to qdisc_put() and that was the check for a NULL pointer, causing oopses. (See upstream commit: 6efb971ba8edfbd80b666f29de12882852f095ae) This patch fixes that. Fixes: 92833e8b5db6c209e9311ac8c6a44d3bf1856659 Reported-by: Thorsten Glaser <tg@xxxxxxxxx> Link: https://bugs.debian.org/1013299 Signed-off-by: Diederik de Haas <didi.debian@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/sched/sch_generic.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -970,8 +970,6 @@ static void qdisc_destroy(struct Qdisc * const struct Qdisc_ops *ops; struct sk_buff *skb, *tmp; - if (!qdisc) - return; ops = qdisc->ops; #ifdef CONFIG_NET_SCHED @@ -1003,6 +1001,9 @@ static void qdisc_destroy(struct Qdisc * void qdisc_put(struct Qdisc *qdisc) { + if (!qdisc) + return; + if (qdisc->flags & TCQ_F_BUILTIN || !refcount_dec_and_test(&qdisc->refcnt)) return; Patches currently in stable-queue which might be from didi.debian@xxxxxxxxx are queue-4.19/net-sched-move-null-ptr-check-to-qdisc_put-too.patch