svn commit: r284245 - head/sys/netinet
Julien Charbon
jch at freebsd.org
Thu Jun 11 13:18:20 UTC 2015
Hi John,
On 10/06/15 17:32, John Baldwin wrote:
> On 6/10/15 4:43 PM, Julien Charbon wrote:
>> Author: jch
>> Date: Wed Jun 10 20:43:07 2015
>> New Revision: 284245
>> URL: https://svnweb.freebsd.org/changeset/base/284245
>>
>> Log:
>> Fix a callout race condition introduced in TCP timers callouts with r281599.
>> In TCP timer context, it is not enough to check callout_stop() return value
>> to decide if a callout is still running or not, previous callout_reset()
>> return values have also to be checked.
>>
>> Differential Revision: https://reviews.freebsd.org/D2763
>> Reviewed by: hiren
>> Approved by: hiren
>> MFC after: 1 day
>> Sponsored by: Verisign, Inc.
>>
>> Modified:
>> head/sys/netinet/tcp_timer.c
>> head/sys/netinet/tcp_timer.h
>>
>> Modified: head/sys/netinet/tcp_timer.c
>> ==============================================================================
>> --- head/sys/netinet/tcp_timer.c Wed Jun 10 20:11:28 2015 (r284244)
>> +++ head/sys/netinet/tcp_timer.c Wed Jun 10 20:43:07 2015 (r284245)
>> @@ -347,11 +347,12 @@ tcp_timer_2msl(void *xtp)
>> tp = tcp_close(tp);
>> } else {
>> if (tp->t_state != TCPS_TIME_WAIT &&
>> - ticks - tp->t_rcvtime <= TP_MAXIDLE(tp))
>> - callout_reset_on(&tp->t_timers->tt_2msl,
>> - TP_KEEPINTVL(tp), tcp_timer_2msl, tp,
>> - inp_to_cpuid(inp));
>> - else
>> + ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) {
>> + if (!callout_reset(&tp->t_timers->tt_2msl,
>> + TP_KEEPINTVL(tp), tcp_timer_2msl, tp)) {
>> + tp->t_timers->tt_flags &= ~TT_2MSL_RST;
>> + }
>> + } else
>> tp = tcp_close(tp);
>
> Did you mean to use callout_reset() instead of callout_reset_on() here and
> elsewhere in this change?
Thanks for this question. Exactly, the goal here is to make clear that
once a TCP timer callout is scheduled on a core, we always reset this
callout on the same core.
It was already the case before, but having only one callout_reset_on()
call in tcp_timer_activate() when we start callout the first time, and
callout_reset() calls everywhere else make it (hopefully) clearer.
My 2 cents.
--
Julien
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 496 bytes
Desc: OpenPGP digital signature
URL: <http://lists.freebsd.org/pipermail/svn-src-all/attachments/20150611/54c9f184/attachment.sig>
More information about the svn-src-all
mailing list