From: Oleg Nesterov <oleg@redhat.com>
To: Eric Dumazet <eric.dumazet@gmail.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, 1 Aug 2009 08:44:38 +0200 [thread overview]
Message-ID: <20090801064438.GA30800@redhat.com> (raw)
In-Reply-To: <4A73DCBE.7080309@gmail.com>
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.
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.
next prev parent reply other threads:[~2009-08-01 6:55 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-31 21:42 + execve-must-clear-current-clear_child_tid.patch added to -mm tree akpm
2009-07-31 22:29 ` 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 [this message]
2009-08-01 7:52 ` Eric Dumazet
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