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 <[email protected]>
---
net/sctp/stream_sched.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/sctp/stream_sched.c b/net/sctp/stream_sched.c
index 518b1b9bf89..1ad565ed562 100644
--- a/net/sctp/stream_sched.c
+++ b/net/sctp/stream_sched.c
@@ -160,7 +160,7 @@ 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;
}
--
2.17.1
Hi,
On Sat, Jul 23, 2022 at 09:58:09AM +0800, Duoming Zhou wrote:
> 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
This sequence is odd but it is used when handling dup cookies. It
tears down whatever was in there and re-inits it. With that,
Acked-by: Marcelo Ricardo Leitner <[email protected]>
> sctp_sched_set_sched
> n->init_sid(..,GFP_KERNEL)
> sctp_sched_prio_init_sid //may sleep
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:
On Sat, 23 Jul 2022 09:58:09 +0800 you wrote:
> 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.
>
> [...]
Here is the summary with links:
- [net] sctp: fix sleep in atomic context bug in timer handlers
https://git.kernel.org/netdev/net/c/b89fc26f741d
You are awesome, thank you!
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