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From: Alexey Dobriyan <adobriyan@gmail.com>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Nathan Zimmer <nzimmer@sgi.com>,
	linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	David Woodhouse <dwmw2@infradead.org>
Subject: Re: [PATCH] fs/proc: Move kfree outside pde_unload_lock
Date: Wed, 29 Aug 2012 16:50:50 +0300	[thread overview]
Message-ID: <CACVxJT_ZRvznb3M=jq_du_aJvRmjcAb3=LSXFGYFWe5W2xo93A@mail.gmail.com> (raw)
In-Reply-To: <1346213517.2522.2.camel@edumazet-glaptop>

On Wed, Aug 29, 2012 at 7:11 AM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> I'll polish this patch once LKS/LPC is over...

It should oops in the following way (excuse Gmail please):
PDEO is removed from lists
->pde_users is 0
PDE won't be in purge queue -- no ->release while module is alive

Current code removes PDEO and checks if PDE scheduled for removal atomically.

proc_reg_release                                        remove_proc_entry

                                                        de->proc_fops = NULL;
release = pde_opener_del(inode, file);
rcu_read_lock();
                                                        synchronize_rcu();
fops = rcu_dereference(pde->proc_fops);
if (!fops) {
        rcu_read_unlock();
                         ----------------------------------
                                                        /* NOP */
                                                        while
(atomic_read(&de->pde_users))
                                                                ...
                                                        /* NOP */

pde_openers_purge(de, &purge_queue);
                                                        /* NOP */
                                                        while
(!list_empty(&purge_queue))
                                                                ...
                                                        rmmod

        if (release)
                release(inode, file) /* OOPS */

  parent reply	other threads:[~2012-08-29 13:50 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-22 16:38 [PATCH] fs/proc: Move kfree outside pde_unload_lock Nathan Zimmer
2012-08-22 16:38 ` [PATCH] fs/prof: Update comment on pde_unload_lock Nathan Zimmer
2012-08-22 18:28 ` [PATCH] fs/proc: Move kfree outside pde_unload_lock Eric Dumazet
2012-08-22 21:42   ` Eric Dumazet
2012-08-23 17:54     ` Nathan Zimmer
2012-08-24 14:48     ` Nathan Zimmer
2012-08-24 14:58       ` Eric Dumazet
2012-08-24 16:45         ` Nathan Zimmer
2012-08-24 21:43           ` Nathan Zimmer
2012-08-28 20:38     ` Alexey Dobriyan
2012-08-29  4:11       ` Eric Dumazet
2012-08-29  8:32         ` Alexey Dobriyan
2012-08-29 13:50         ` Alexey Dobriyan [this message]
2012-08-29 14:24           ` Eric Dumazet
2012-09-17 15:57             ` Nathan Zimmer

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