Commit b89fc26f authored by Duoming Zhou's avatar Duoming Zhou Committed by Jakub Kicinski

sctp: fix sleep in atomic context bug in timer handlers

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: 5bbbbe32 ("sctp: introduce stream scheduler foundations")
Signed-off-by: default avatarDuoming Zhou <duoming@zju.edu.cn>
Acked-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://lore.kernel.org/r/20220723015809.11553-1-duoming@zju.edu.cnSigned-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c7560d12
...@@ -160,7 +160,7 @@ int sctp_sched_set_sched(struct sctp_association *asoc, ...@@ -160,7 +160,7 @@ int sctp_sched_set_sched(struct sctp_association *asoc,
if (!SCTP_SO(&asoc->stream, i)->ext) if (!SCTP_SO(&asoc->stream, i)->ext)
continue; continue;
ret = n->init_sid(&asoc->stream, i, GFP_KERNEL); ret = n->init_sid(&asoc->stream, i, GFP_ATOMIC);
if (ret) if (ret)
goto err; goto err;
} }
......
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