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authorMaciej Kwiecien <maciej.kwiecien@nokia.com>2019-02-22 11:45:26 +0300
committerDavid S. Miller <davem@davemloft.net>2019-02-22 22:11:54 +0300
commitd1f20c03f48102e52eb98b8651d129b83134cae4 (patch)
treecfee49528aa255f4e0f12f2d05d9b8d0d165d04f /net
parent6321aa197547da397753757bd84c6ce64b3e3d89 (diff)
downloadlinux-d1f20c03f48102e52eb98b8651d129b83134cae4.tar.xz
sctp: don't compare hb_timer expire date before starting it
hb_timer might not start at all for a particular transport because its start is conditional. In a result a node is not sending heartbeats. Function sctp_transport_reset_hb_timer has two roles: - initial start of hb_timer for a given transport, - update expire date of hb_timer for a given transport. The function is optimized to update timer's expire only if it is before a new calculated one but this comparison is invalid for a timer which has not yet started. Such a timer has expire == 0 and if a new expire value is bigger than (MAX_JIFFIES / 2 + 2) then "time_before" macro will fail and timer will not start resulting in no heartbeat packets send by the node. This was found when association was initialized within first 5 mins after system boot due to jiffies init value which is near to MAX_JIFFIES. Test kernel version: 4.9.154 (ARCH=arm) hb_timer.expire = 0; //initialized, not started timer new_expire = MAX_JIFFIES / 2 + 2; //or more time_before(hb_timer.expire, new_expire) == false Fixes: ba6f5e33bdbb ("sctp: avoid refreshing heartbeat timer too often") Reported-by: Marcin Stojek <marcin.stojek@nokia.com> Tested-by: Marcin Stojek <marcin.stojek@nokia.com> Signed-off-by: Maciej Kwiecien <maciej.kwiecien@nokia.com> Reviewed-by: Alexander Sverdlin <alexander.sverdlin@nokia.com> Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/sctp/transport.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/net/sctp/transport.c b/net/sctp/transport.c
index 033696e6f74f..ad158d311ffa 100644
--- a/net/sctp/transport.c
+++ b/net/sctp/transport.c
@@ -207,7 +207,8 @@ 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) &&
+ if ((time_before(transport->hb_timer.expires, expires) ||
+ !timer_pending(&transport->hb_timer)) &&
!mod_timer(&transport->hb_timer,
expires + prandom_u32_max(transport->rto)))
sctp_transport_hold(transport);