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| author | Maciej Kwiecien <maciej.kwiecien@nokia.com> | 2019-02-22 09:45:26 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-02-22 11:11:54 -0800 |
| commit | d1f20c03f48102e52eb98b8651d129b83134cae4 (patch) | |
| tree | cfee49528aa255f4e0f12f2d05d9b8d0d165d04f /net/sctp | |
| parent | 6321aa197547da397753757bd84c6ce64b3e3d89 (diff) | |
| download | linux-d1f20c03f48102e52eb98b8651d129b83134cae4.tar.gz linux-d1f20c03f48102e52eb98b8651d129b83134cae4.tar.bz2 linux-d1f20c03f48102e52eb98b8651d129b83134cae4.zip | |
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/sctp')
| -rw-r--r-- | net/sctp/transport.c | 3 |
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); |