Eric Dumazet ed2e923945 tcp/dccp: fix timewait races in timer handling ... When creating a timewait socket, we need to arm the timer before allowing other cpus to find it. The signal allowing cpus to find the socket is setting tw_refcnt to non zero value. As we set tw_refcnt in __inet_twsk_hashdance(), we therefore need to call inet_twsk_schedule() first. This also means we need to remove tw_refcnt changes from inet_twsk_schedule() and let the caller handle it. Note that because we use mod_timer_pinned(), we have the guarantee the timer wont expire before we set tw_refcnt as we run in BH context. To make things more readable I introduced inet_twsk_reschedule() helper. When rearming the timer, we can use mod_timer_pending() to make sure we do not rearm a canceled timer. Note: This bug can possibly trigger if packets of a flow can hit multiple cpus. This does not normally happen, unless flow steering is broken somehow. This explains this bug was spotted ~5 months after its introduction. A similar fix is needed for SYN_RECV sockets in reqsk_queue_hash_req(), but will be provided in a separate patch for proper tracking. Fixes: 789f558cfb ("tcp/dccp: get rid of central timewait timer") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Ying Cai <ycai@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>		2015-09-21 16:32:29 -07:00
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ccids
ackvec.c
ackvec.h
ccid.c
ccid.h
dccp.h
diag.c
feat.c
feat.h
input.c
ipv4.c
ipv6.c
ipv6.h
Kconfig
Makefile
minisocks.c	tcp/dccp: fix timewait races in timer handling	2015-09-21 16:32:29 -07:00
options.c
output.c
probe.c
proto.c
qpolicy.c
sysctl.c
timer.c