From: Andrew Morton <akpm@linux-foundation.org>
To: David Rientjes <rientjes@google.com>
Cc: Dave Jones <davej@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch] mm, hugetlb: add thread name and pid to SHM_HUGETLB mlock rlimit warning
Date: Thu, 8 Mar 2012 12:02:38 -0800 [thread overview]
Message-ID: <20120308120238.c4486547.akpm@linux-foundation.org> (raw)
In-Reply-To: <alpine.DEB.2.00.1203061825070.9015@chino.kir.corp.google.com>
On Tue, 6 Mar 2012 18:26:11 -0800 (PST)
David Rientjes <rientjes@google.com> wrote:
> Add the thread name and pid of the application that is allocating shm
> segments with MAP_HUGETLB without being a part of
> /proc/sys/vm/hugetlb_shm_group or having CAP_IPC_LOCK.
>
> This identifies the application so it may be fixed by avoiding using the
> deprecated exception (see Documentation/feature-removal-schedule.txt).
>
> ...
>
> --- a/fs/hugetlbfs/inode.c
> +++ b/fs/hugetlbfs/inode.c
> @@ -946,7 +946,11 @@ struct file *hugetlb_file_setup(const char *name, size_t size,
> if (creat_flags == HUGETLB_SHMFS_INODE && !can_do_hugetlb_shm()) {
> *user = current_user();
> if (user_shm_lock(size, *user)) {
> - printk_once(KERN_WARNING "Using mlock ulimits for SHM_HUGETLB is deprecated\n");
> + task_lock(current);
> + printk_once(KERN_WARNING
> + "%s (%d): Using mlock ulimits for SHM_HUGETLB is deprecated\n",
> + current->comm, current->pid);
> + task_unlock(current);
I assume the task_lock() is there to protect current->comm. If so, it
is unneeded - we're protecting against prctl(PR_SET_NAME), and
PR_SET_NAME only operates on current, and we know this task isn't
currently running PR_SET_NAME.
If there's a way for another task to alter this task's ->comm then we
_do_ need locking. But there isn't a way, I hope.
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next prev parent reply other threads:[~2012-03-08 20:02 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-07 2:26 [patch] mm, hugetlb: add thread name and pid to SHM_HUGETLB mlock rlimit warning David Rientjes
2012-03-08 20:02 ` Andrew Morton [this message]
2012-03-08 21:37 ` David Rientjes
2012-03-08 21:56 ` Andrew Morton
2012-03-08 22:08 ` David Rientjes
2012-03-08 22:23 ` Andrew Morton
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