This is a note to let you know that I've just added the patch titled
sctp: do not check hb_timer.expires when resetting hb_timer
to the 4.14-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-do-not-check-hb_timer.expires-when-resetting-hb.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f2101fdcb7a5483f2f2982bb9045d281b3fb17db
Author: Xin Long <lucien.xin@xxxxxxxxx>
Date: Mon Jan 30 11:25:33 2023 -0500
sctp: do not check hb_timer.expires when resetting hb_timer
[ Upstream commit 8f35ae17ef565a605de5f409e04bcd49a55d7646 ]
It tries to avoid the frequently hb_timer refresh in commit ba6f5e33bdbb
("sctp: avoid refreshing heartbeat timer too often"), and it only allows
mod_timer when the new expires is after hb_timer.expires. It means even
a much shorter interval for hb timer gets applied, it will have to wait
until the current hb timer to time out.
In sctp_do_8_2_transport_strike(), when a transport enters PF state, it
expects to update the hb timer to resend a heartbeat every rto after
calling sctp_transport_reset_hb_timer(), which will not work as the
change mentioned above.
The frequently hb_timer refresh was caused by sctp_transport_reset_timers()
called in sctp_outq_flush() and it was already removed in the commit above.
So we don't have to check hb_timer.expires when resetting hb_timer as it is
now not called very often.
Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often")
Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Link: https://lore.kernel.org/r/d958c06985713ec84049a2d5664879802710179a.1675095933.git.lucien.xin@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index af56651169b2..79d2aa44c6e5 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -210,9 +210,7 @@ void sctp_transport_reset_hb_timer(struct sctp_transport *transport)
/* When a data chunk is sent, reset the heartbeat interval. */
expires = jiffies + sctp_transport_timeout(transport);
- if ((time_before(transport->hb_timer.expires, expires) ||
- !timer_pending(&transport->hb_timer)) &&
- !mod_timer(&transport->hb_timer,
+ if (!mod_timer(&transport->hb_timer,
expires + prandom_u32_max(transport->rto)))
sctp_transport_hold(transport);
}
