This is a note to let you know that I've just added the patch titled sctp: fix sleep in atomic context bug in timer handlers to the 5.10-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: sctp-fix-sleep-in-atomic-context-bug-in-timer-handle.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit d4e50ac92fae9fe0b48e5348b08b74dcb8e8ee31 Author: Duoming Zhou <duoming@xxxxxxxxxx> Date: Sat Jul 23 09:58:09 2022 +0800 sctp: fix sleep in atomic context bug in timer handlers [ Upstream commit b89fc26f741d9f9efb51cba3e9b241cf1380ec5a ] There are sleep in atomic context bugs in timer handlers of sctp such as sctp_generate_t3_rtx_event(), sctp_generate_probe_event(), sctp_generate_t1_init_event(), sctp_generate_timeout_event(), sctp_generate_t3_rtx_event() and so on. The root cause is sctp_sched_prio_init_sid() with GFP_KERNEL parameter that may sleep could be called by different timer handlers which is in interrupt context. One of the call paths that could trigger bug is shown below: (interrupt context) sctp_generate_probe_event sctp_do_sm sctp_side_effects sctp_cmd_interpreter sctp_outq_teardown sctp_outq_init sctp_sched_set_sched n->init_sid(..,GFP_KERNEL) sctp_sched_prio_init_sid //may sleep This patch changes gfp_t parameter of init_sid in sctp_sched_set_sched() from GFP_KERNEL to GFP_ATOMIC in order to prevent sleep in atomic context bugs. Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations") Signed-off-by: Duoming Zhou <duoming@xxxxxxxxxx> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx> Link: https://lore.kernel.org/r/20220723015809.11553-1-duoming@xxxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/sctp/stream_sched.c b/net/sctp/stream_sched.c index 99e5f69fbb74..a2e1d34f52c5 100644 --- a/net/sctp/stream_sched.c +++ b/net/sctp/stream_sched.c @@ -163,7 +163,7 @@ int sctp_sched_set_sched(struct sctp_association *asoc, if (!SCTP_SO(&asoc->stream, i)->ext) continue; - ret = n->init_sid(&asoc->stream, i, GFP_KERNEL); + ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC); if (ret) goto err; }