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From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
	Eric Dumazet <eric.dumazet@gmail.com>,
	David Miller <davem@davemloft.net>,
	Jason Baron <jbaron@akamai.com>,
	kgraul@linux.ibm.com, ktkhai@virtuozzo.com,
	kyeongdon.kim@lge.com,
	Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
	Netdev <netdev@vger.kernel.org>,
	pabeni@redhat.com, syzkaller-bugs@googlegroups.com,
	xiyou.wangcong@gmail.com, zhengbin <zhengbin13@huawei.com>,
	bcrl@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-aio@kvack.org, houtao1@huawei.com, yi.zhang@huawei.com
Subject: Re: [PATCH 3/8] aio: store event at final iocb_put()
Date: Mon, 11 Mar 2019 22:52:30 +0000	[thread overview]
Message-ID: <20190311225230.GP2217@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190311211328.GN2217@ZenIV.linux.org.uk>

On Mon, Mar 11, 2019 at 09:13:28PM +0000, Al Viro wrote:
> On Mon, Mar 11, 2019 at 08:44:31PM +0100, Christoph Hellwig wrote:
> > On Sun, Mar 10, 2019 at 07:08:17AM +0000, Al Viro wrote:
> > > From: Al Viro <viro@zeniv.linux.org.uk>
> > > 
> > > Instead of having aio_complete() set ->ki_res.{res,res2}, do that
> > > explicitly in its callers, drop the reference (as aio_complete()
> > > used to do) and delay the rest until the final iocb_put().
> > > 
> > > Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> > > ---
> > >  fs/aio.c | 45 ++++++++++++++++++++-------------------------
> > >  1 file changed, 20 insertions(+), 25 deletions(-)
> > > 
> > > diff --git a/fs/aio.c b/fs/aio.c
> > > index 2249a7a1d6b3..b9c4c1894020 100644
> > > --- a/fs/aio.c
> > > +++ b/fs/aio.c
> > > @@ -1077,24 +1077,10 @@ static inline void iocb_destroy(struct aio_kiocb *iocb)
> > >  	kmem_cache_free(kiocb_cachep, iocb);
> > >  }
> > >  
> > > -static inline void iocb_put(struct aio_kiocb *iocb)
> > > -{
> > > -	if (refcount_dec_and_test(&iocb->ki_refcnt))
> > > -		iocb_destroy(iocb);
> > > -}
> > 
> > Maybe iocb_put should just have been added in the place you move
> > it to in patch 1?
> 
> Might as well...

Actually, that wouldn't be any better - it would need at least a declaration
before aio_complete(), since in the original patch aio_complete() calls it.
So that wouldn't be less noisy...

  reply	other threads:[~2019-03-11 22:52 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-03 10:22 KASAN: use-after-free Read in unix_dgram_poll syzbot
2019-03-03 13:55 ` Al Viro
2019-03-03 15:18   ` [PATCH] aio: prevent the final fput() in the middle of vfs_poll() (Re: KASAN: use-after-free Read in unix_dgram_poll) Al Viro
2019-03-03 18:37     ` Eric Dumazet
2019-03-03 19:44     ` Linus Torvalds
2019-03-03 20:13       ` Linus Torvalds
2019-03-03 20:30       ` Al Viro
2019-03-03 22:23         ` Linus Torvalds
2019-03-04  2:36           ` Al Viro
2019-03-04 21:22             ` Linus Torvalds
2019-03-07  0:03               ` [PATCH 1/8] aio: make sure file is pinned Al Viro
2019-03-07  0:03                 ` [PATCH 2/8] aio_poll_wake(): don't set ->woken if we ignore the wakeup Al Viro
2019-03-07  2:18                   ` Al Viro
2019-03-08 11:16                     ` zhengbin (A)
2019-03-07  0:03                 ` [PATCH 3/8] aio_poll(): sanitize the logics after vfs_poll(), get rid of leak on error Al Viro
2019-03-07  2:11                   ` zhengbin (A)
2019-03-07  0:03                 ` [PATCH 4/8] aio_poll(): get rid of weird refcounting Al Viro
2019-03-07  0:03                 ` [PATCH 5/8] make aio_read()/aio_write() return int Al Viro
2019-03-07  0:03                 ` [PATCH 6/8] move dropping ->ki_eventfd into iocb_put() Al Viro
2019-03-07  0:03                 ` [PATCH 7/8] deal with get_reqs_available() in aio_get_req() itself Al Viro
2019-03-07  0:03                 ` [PATCH 8/8] aio: move sanity checks and request allocation to io_submit_one() Al Viro
2019-03-07  0:23                 ` [PATCH 1/8] aio: make sure file is pinned Linus Torvalds
2019-03-07  0:41                   ` Al Viro
2019-03-07  0:48                     ` Al Viro
2019-03-07  1:20                       ` Al Viro
2019-03-07  1:30                         ` Linus Torvalds
2019-03-08  3:36                           ` Al Viro
2019-03-08 15:50                             ` Christoph Hellwig
2019-03-10  7:06                             ` Al Viro
2019-03-10  7:08                               ` [PATCH 1/8] pin iocb through aio Al Viro
2019-03-10  7:08                                 ` [PATCH 2/8] keep io_event in aio_kiocb Al Viro
2019-03-11 19:43                                   ` Christoph Hellwig
2019-03-11 21:17                                     ` Al Viro
2019-03-10  7:08                                 ` [PATCH 3/8] aio: store event at final iocb_put() Al Viro
2019-03-11 19:44                                   ` Christoph Hellwig
2019-03-11 21:13                                     ` Al Viro
2019-03-11 22:52                                       ` Al Viro [this message]
2019-03-10  7:08                                 ` [PATCH 4/8] Fix aio_poll() races Al Viro
2019-03-11 19:58                                   ` Christoph Hellwig
2019-03-11 21:06                                     ` Al Viro
2019-03-12 19:18                                       ` Christoph Hellwig
2019-03-10  7:08                                 ` [PATCH 5/8] make aio_read()/aio_write() return int Al Viro
2019-03-11 19:44                                   ` Christoph Hellwig
2019-03-10  7:08                                 ` [PATCH 6/8] move dropping ->ki_eventfd into iocb_destroy() Al Viro
2019-03-11 19:46                                   ` Christoph Hellwig
2019-03-10  7:08                                 ` [PATCH 7/8] deal with get_reqs_available() in aio_get_req() itself Al Viro
2019-03-11 19:46                                   ` Christoph Hellwig
2019-03-10  7:08                                 ` [PATCH 8/8] aio: move sanity checks and request allocation to io_submit_one() Al Viro
2019-03-11 19:48                                   ` Christoph Hellwig
2019-03-11 21:12                                     ` Al Viro
2019-03-11 19:41                                 ` [PATCH 1/8] pin iocb through aio Christoph Hellwig
2019-03-11 19:41                               ` [PATCH 1/8] aio: make sure file is pinned Christoph Hellwig
2019-03-04  7:53     ` [PATCH] aio: prevent the final fput() in the middle of vfs_poll() (Re: KASAN: use-after-free Read in unix_dgram_poll) Dmitry Vyukov

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