linux-kernel - Re: [PATCH] posixtimers: Fix posix clock monotonicity

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <49BF43A8.1040808@jp.fujitsu.com>
Date:	Tue, 17 Mar 2009 15:31:04 +0900
From:	Hidetoshi Seto <seto.hidetoshi@...fujitsu.com>
To:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
CC:	linux-kernel@...r.kernel.org, stable@...nel.org
Subject: Re: [PATCH] posixtimers: Fix posix clock monotonicity

KAMEZAWA Hiroyuki wrote:
> Hidetoshi Seto <seto.hidetoshi@...fujitsu.com> wrote:
> 
>> This patch rehires task_sched_runtime() and thread_group_sched_runtime()
>> which were removed at the time of 2.6.28-rc1.
>>
>> These functions protect the sampling of clock with rq lock.
>> This rq lock is required not to update rq->clock during the sampling.
>> i.e. You may get ((banked runtime before update)+(delta after update)).
>>
> Does clock_gettime() go backward without lock ?

Yes, that's right.

You can find the ancestor of this patch here:
 [RESEND][PATCH] posixtimers: clock_gettime(CLOCK_*_CPUTIME_ID) goes backward
  http://lkml.org/lkml/2009/1/27/18

After the last post, I dug the git-log and found that there were functions,
task_sched_runtime() and thread_group_sched_runtime(), worked fine at the
time of 2.6.27.  I think it is better to reintroduce these functions again
than making almost same function with different name.

Thanks,
H.Seto

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/