MIME-Version: 1.0
In-Reply-To: <20120228170436.GA9698@redhat.com>
References: <20120228170436.GA9698@redhat.com>
Date: Tue, 28 Feb 2012 22:48:18 +0530
Message-ID: <CAAHN_R1hmJt4zCxGAL7z2-9URmWUFwwV9pcqkdvQZodpunEJjQ@mail.gmail.com>
Subject: Re: + procfs-mark-thread-stack-correctly-in-proc-pid-maps.patch added
 to -mm tree
From: Siddhesh Poyarekar <siddhesh.poyarekar@gmail.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Jamie Lokier <jamie@shareable.org>, Mike Frysinger <vapier@gentoo.org>,
        Alexey Dobriyan <adobriyan@gmail.com>, Matt Mackall <mpm@selenic.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1100
Lines: 33

On Tue, Feb 28, 2012 at 10:34 PM, Oleg Nesterov <oleg@redhat.com> wrote:
>> +int vm_is_stack(struct task_struct *task,
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? struct vm_area_struct *vma, int in_group)
>> +{
>> + ? ? if (vm_is_stack_for_task(task, vma))
>> + ? ? ? ? ? ? return 1;
>> +
>> + ? ? if (in_group) {
>> + ? ? ? ? ? ? struct task_struct *t = task;
>> + ? ? ? ? ? ? while_each_thread(task, t) {
>> + ? ? ? ? ? ? ? ? ? ? if (vm_is_stack_for_task(t, vma))
>> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? return 1;
>> + ? ? ? ? ? ? }
>> + ? ? }
>> +
>> + ? ? return 0;
>> +}
>
> This is obviously wrong, while_each_thread() is not safe without
> tasklist or siglock or rcu.

I have fixed this in my git stash. I'll submit once I get to work on
Mike Frysinger's idea of marking stacks with their tids and see if it
breaks anything.

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