From: Eric Dumazet <eric.dumazet@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, drepper@redhat.com,
jens@mcbone.net, mingo@elte.hu, peterz@infradead.org,
sonnyrao@us.ibm.com, stable@kernel.org, tglx@linutronix.de
Subject: Re: [PATCH v2] execve: must clear current->clear_child_tid
Date: Sat, 01 Aug 2009 09:52:46 +0200 [thread overview]
Message-ID: <4A73F44E.1010508@gmail.com> (raw)
In-Reply-To: <20090801064438.GA30800@redhat.com>
Oleg Nesterov a écrit :
> On 08/01, Eric Dumazet wrote:
>> I only wonder about core dumping, since mm_release() is also used by exiting tasks.
>>
>> Isnt clear_child_tid used by gdb or other debugger ?
>
> Afaics it is not...
>
> At least, I can't see how gdb (or any other user-space app) can figure
> out the value of ->clear_child_tid.
>
Yep, this was from old Unixes time, when core file included the 'u' structure ...
Dont worry ;)
>
>
> Not that this really matters, but please note also that it is possible
> that the coredumping task has ->clear_child_tid == NULL anyway, even
> without this change. The PF_SIGNALED check in mm_release() is not 100&
> reliable.
>
> Suppose a thread T sleeps in do_exit()->ptrace_event(PT_TRACE_EXIT) path.
> Another thread starts a coredump and kills T via zap_process(). This wakes
> up T, it calls exit_mm()->mm_release() without PF_SIGNALED.
>
> Oleg.
>
prev parent reply other threads:[~2009-08-01 7:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <200907312142.n6VLgKfx021454@imap1.linux-foundation.org>
2009-07-31 22:29 ` + execve-must-clear-current-clear_child_tid.patch added to -mm tree Oleg Nesterov
2009-08-01 0:38 ` Linus Torvalds
2009-08-01 0:51 ` Andrew Morton
2009-08-01 1:54 ` [PATCH v2] execve: must clear current->clear_child_tid Oleg Nesterov
2009-08-01 6:12 ` Eric Dumazet
2009-08-01 6:44 ` Oleg Nesterov
2009-08-01 7:52 ` Eric Dumazet [this message]
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