mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![]() 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:
|
||
---|---|---|
.. | ||
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 | ||
options.c | ||
output.c | ||
probe.c | ||
proto.c | ||
qpolicy.c | ||
sysctl.c | ||
timer.c |