From: Simon Horman <horms@kernel.org>
To: Chengfeng Ye <dg573847474@gmail.com>
Cc: jreuter@yaina.de, ralf@linux-mips.org, davem@davemloft.net,
edumazet@google.com, kuba@kernel.org, pabeni@redhat.com,
linux-hams@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] ax25: Fix potential deadlock on &ax25_list_lock
Date: Sat, 7 Oct 2023 17:10:21 +0200 [thread overview]
Message-ID: <20231007151021.GC831234@kernel.org> (raw)
In-Reply-To: <20231005072349.52602-1-dg573847474@gmail.com>
On Thu, Oct 05, 2023 at 07:23:49AM +0000, Chengfeng Ye wrote:
> Timer interrupt ax25_ds_timeout() could introduce double locks on
> &ax25_list_lock.
>
> ax25_ioctl()
> --> ax25_ctl_ioctl()
> --> ax25_dama_off()
> --> ax25_dev_dama_off()
> --> ax25_check_dama_slave()
> --> spin_lock(&ax25_list_lock)
> <timer interrupt>
> --> ax25_ds_timeout()
> --> spin_lock(&ax25_list_lock)
>
> This flaw was found by an experimental static analysis tool I am
> developing for irq-related deadlock.
>
> To prevent the potential deadlock, the patch use spin_lock_bh()
> on &ax25_list_lock inside ax25_check_dama_slave().
>
> Fixes: c19c4b9c9acb ("[AX.25]: Optimize AX.25 socket list lock")
> Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Hi Chengfeng Ye,
Are there other functions that spin_lock(&ax25_list_lock)
that also need to use spin_lock_bh()?
...
next prev parent reply other threads:[~2023-10-07 15:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-05 7:23 [PATCH V2] ax25: Fix potential deadlock on &ax25_list_lock Chengfeng Ye
2023-10-07 15:10 ` Simon Horman [this message]
2023-10-07 15:43 ` Chengfeng Ye
2023-10-09 14:55 ` Simon Horman
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