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: 5bbbbe3 ("sctp: introduce stream scheduler foundations") Signed-off-by: Duoming Zhou <duoming@zju.edu.cn> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Link: https://lore.kernel.org/r/20220723015809.11553-1-duoming@zju.edu.cn Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>

Author: stonezdm

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;
 }