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From: Eric Dumazet <edumazet@google.com>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Paolo Abeni <pabeni@redhat.com>,
	patchwork-bot+netdevbpf@kernel.org,
	Santosh Shilimkar <santosh.shilimkar@oracle.com>,
	David Miller <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	syzbot <syzbot+694120e1002c117747ed@syzkaller.appspotmail.com>,
	netdev <netdev@vger.kernel.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	linux-rdma <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH net v2] net: rds: use maybe_get_net() when acquiring refcount on TCP sockets
Date: Thu, 5 May 2022 12:13:37 -0700	[thread overview]
Message-ID: <CANn89iJaairJwd9rqWuTH3vibanugMTG3_4mX3yoqgrNiqHEeA@mail.gmail.com> (raw)
In-Reply-To: <41d09faf-bc78-1a87-dfd1-c6d1b5984b61@I-love.SAKURA.ne.jp>

On Wed, May 4, 2022 at 6:54 PM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>
> Eric Dumazet is reporting addition on 0 problem at rds_tcp_tune(), for
> delayed works queued in rds_wq might be invoked after a net namespace's
> refcount already reached 0.
>
> Since rds_tcp_exit_net() from cleanup_net() calls flush_workqueue(rds_wq),
> it is guaranteed that we can instead use maybe_get_net() from delayed work
> functions until rds_tcp_exit_net() returns.
>
> Note that I'm not convinced that all works which might access a net
> namespace are already queued in rds_wq by the moment rds_tcp_exit_net()
> calls flush_workqueue(rds_wq). If some race is there, rds_tcp_exit_net()
> will fail to wait for work functions, and kmem_cache_free() could be
> called from net_free() before maybe_get_net() is called from
> rds_tcp_tune().
>
> Reported-by: Eric Dumazet <edumazet@google.com>
> Fixes: 3a58f13a881ed351 ("net: rds: acquire refcount on TCP sockets")
> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> ---
>

Reviewed-by: Eric Dumazet <edumazet@google.com>

  reply	other threads:[~2022-05-05 19:13 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-24  7:40 KASAN: use-after-free Read in tcp_retransmit_timer (5) syzbot
2021-12-22 11:00 ` [syzbot] " syzbot
2022-04-09  8:19   ` Tetsuo Handa
2022-04-09 16:46     ` Eric Dumazet
2022-04-09 17:47       ` Eric Dumazet
2022-04-09 17:55         ` Eric Dumazet
2022-04-10  0:38           ` Tetsuo Handa
2022-04-10  5:39             ` Tetsuo Handa
2022-04-10 11:36         ` Tetsuo Handa
2022-04-22 14:40     ` Tetsuo Handa
2022-04-24  3:57       ` Tetsuo Handa
2022-05-01 15:29         ` [PATCH] net: rds: acquire refcount on TCP sockets Tetsuo Handa
2022-05-01 16:14           ` Eric Dumazet
2022-05-02  1:40             ` [PATCH v2] " Tetsuo Handa
2022-05-02 14:12               ` Haakon Bugge
2022-05-02 14:29                 ` Tetsuo Handa
2022-05-03  9:02               ` Paolo Abeni
2022-05-03  9:56                 ` Tetsuo Handa
2022-05-03 11:10                   ` Paolo Abeni
2022-05-03 13:27                 ` David Laight
2022-05-03 13:43                   ` Eric Dumazet
2022-05-03 14:25                     ` David Laight
2022-05-03 13:45                 ` Eric Dumazet
2022-05-03 14:08                   ` Tetsuo Handa
2022-05-03 11:40               ` patchwork-bot+netdevbpf
2022-05-03 21:17                 ` Eric Dumazet
2022-05-03 22:37                   ` Eric Dumazet
2022-05-04  1:04                     ` Tetsuo Handa
2022-05-04  3:09                       ` Eric Dumazet
2022-05-04  4:58                         ` Tetsuo Handa
2022-05-04 15:15                           ` Tetsuo Handa
2022-05-05  0:45                             ` [PATCH] net: rds: use maybe_get_net() when acquiring " Tetsuo Handa
2022-05-05  0:53                               ` Eric Dumazet
2022-05-05  1:04                               ` Jakub Kicinski
2022-05-05  1:53                               ` [PATCH net v2] " Tetsuo Handa
2022-05-05 19:13                                 ` Eric Dumazet [this message]
2022-05-06  1:20                                 ` patchwork-bot+netdevbpf
2022-05-04 13:09                   ` [PATCH v2] net: rds: acquire " Paolo Abeni
2022-05-04 13:25                     ` Eric Dumazet

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