netdev - Re: [PATCH net] mISDN: Fix data race in timer handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aXpJWC8daHd329w9@horms.kernel.org>
Date: Wed, 28 Jan 2026 17:37:28 +0000
From: Simon Horman <horms@...nel.org>
To: Henry Zhang <henryzhangjcle@...il.com>
Cc: netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	tglx@...utronix.de, mingo@...nel.org,
	syzbot+c6e7bcea7ffb7ff46acb@...kaller.appspotmail.com,
	Henry Zhang <zeri@...ch.edu>, Eric Dumazet <edumazet@...gle.com>
Subject: Re: [PATCH net] mISDN: Fix data race in timer handling

+ Eric

On Tue, Jan 27, 2026 at 02:19:27AM -0500, Henry Zhang wrote:
> KCSAN reported a data race where misdn_add_timer() writes dev->work
> while mISDN_read() reads it without holding the spinlock:
> 
> write to 0xffff88812d848280 of 4 bytes by task 10864 on cpu 1:
>  misdn_add_timer drivers/isdn/mISDN/timerdev.c:175 [inline]
> ...
> 
> read to 0xffff88812d848280 of 4 bytes by task 10857 on cpu 0:
>  mISDN_read+0x1f2/0x470 drivers/isdn/mISDN/timerdev.c:112
> ...
> 
> dev->work is read locklessly in wait_event_interruptible() and
> mISDN_poll(). In mISDN_read(), the result is rechecked under dev->lock.
> In mISDN_poll(), a stale value may cause a spurious EPOLLIN or a missed
> wake, but wake_up_interruptible() will correct this. In both cases, the
> race is benign, so we can annotate these with READ_ONCE/WRITE_ONCE.
> 
> Reported-by: syzbot+c6e7bcea7ffb7ff46acb@...kaller.appspotmail.com
> Closes: https://syzkaller.appspot.com/bug?extid=c6e7bcea7ffb7ff46acb
> 
> Signed-off-by: Henry Zhang <zeri@...ch.edu>

Hi Henry,

This appears to already be addressed by
commit 8175dbf174d4 ("mISDN: annotate data-race around dev->work")

-- 
pw-bot: cr