From: Al Viro <viro@ZenIV.linux.org.uk>
To: Ingo Molnar <mingo@kernel.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Waiman Long <Waiman.Long@hp.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
"Chandramouleeswaran, Aswin" <aswin@hp.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>
Subject: Re: spinlock contention of files->file_lock
Date: Wed, 2 Oct 2013 11:20:37 +0100 [thread overview]
Message-ID: <20131002102037.GZ13318@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20131002051319.GB27982@gmail.com>
On Wed, Oct 02, 2013 at 07:13:19AM +0200, Ingo Molnar wrote:
>
> * Al Viro <viro@ZenIV.linux.org.uk> wrote:
>
> > On Tue, Oct 01, 2013 at 02:41:58PM -0700, Eric Dumazet wrote:
> > > Maybe I am missing something obvious ?
> >
> > Yes. do_execve_common() starts with unshare_files(); there can be
> > no other thread capable of modifying that descriptor table.
>
> Btw., might the Android Binder:
>
> drivers/staging/android/binder.c: struct files_struct *files = proc->files;
> ...
> drivers/staging/android/binder.c: __fd_install(proc->files, fd, file);
> ...
> drivers/staging/android/binder.c: retval = __close_fd(proc->files, fd);
>
> violate that assumption?
Not unless your thread has managed to call an ioctl between entering
do_execve_common() and calling do_close_on_exec() ;-)
next prev parent reply other threads:[~2013-10-02 10:20 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-09-30 19:29 Avoiding the dentry d_lock on final dput(), part deux: transactional memory Linus Torvalds
2013-09-30 19:29 ` Linus Torvalds
2013-09-30 20:01 ` Waiman Long
2013-09-30 20:01 ` Waiman Long
2013-09-30 20:04 ` Linus Torvalds
2013-09-30 20:04 ` Linus Torvalds
2013-10-02 14:56 ` Andi Kleen
2013-10-02 14:56 ` Andi Kleen
2013-09-30 22:52 ` Benjamin Herrenschmidt
2013-09-30 22:52 ` Benjamin Herrenschmidt
2013-10-01 0:36 ` Michael Neuling
2013-10-01 0:36 ` Michael Neuling
2013-10-01 0:56 ` Linus Torvalds
2013-10-01 0:56 ` Linus Torvalds
2013-10-01 2:05 ` Benjamin Herrenschmidt
2013-10-01 2:05 ` Benjamin Herrenschmidt
2013-10-01 3:13 ` Paul E. McKenney
2013-10-01 3:13 ` Paul E. McKenney
2013-10-01 4:52 ` Michael Neuling
2013-10-01 4:52 ` Michael Neuling
2013-10-01 12:16 ` Paul E. McKenney
2013-10-01 12:16 ` Paul E. McKenney
2013-10-01 13:42 ` Paul E. McKenney
2013-10-01 13:42 ` Paul E. McKenney
2013-10-01 1:05 ` spinlock contention of files->file_lock Eric Dumazet
2013-10-01 1:44 ` Linus Torvalds
2013-10-01 2:18 ` Eric Dumazet
2013-10-01 21:41 ` Eric Dumazet
2013-10-01 22:04 ` Al Viro
2013-10-01 22:21 ` Eric Dumazet
2013-10-02 5:13 ` Ingo Molnar
2013-10-02 10:20 ` Al Viro [this message]
2013-10-02 10:56 ` Ingo Molnar
2013-10-01 1:53 ` Al Viro
2013-10-01 2:02 ` Linus Torvalds
2013-10-01 3:27 ` Al Viro
2013-10-01 3:36 ` Eric Dumazet
2013-10-01 5:12 ` Eric Dumazet
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