From: Krzysztof Kozlowski <krzk@kernel.org>
To: Deepanshu Kartikey <kartikey406@gmail.com>
Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org,
pabeni@redhat.com, horms@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot+4ef89409a235d804c6c2@syzkaller.appspotmail.com
Subject: Re: [PATCH] net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write
Date: Wed, 17 Dec 2025 09:57:47 +0100 [thread overview]
Message-ID: <5cb165de-12ef-4e6a-ab8a-aefb53bf9f23@kernel.org> (raw)
In-Reply-To: <CADhLXY4pBLt8vLfo8JeZMgfNYD7f=F+zGWTim5HmPyM-7j9THg@mail.gmail.com>
On 17/12/2025 09:11, Deepanshu Kartikey wrote:
>
> rfkill_set_block() calls ops->set_block() (i.e., nfc_rfkill_set_block)
> without releasing rfkill_global_mutex.
>
> Since rfkill_unregister() also acquires rfkill_global_mutex:
>
> void rfkill_unregister(struct rfkill *rfkill)
> {
> ...
> mutex_lock(&rfkill_global_mutex);
> rfkill_send_events(rfkill, RFKILL_OP_DEL);
> list_del_init(&rfkill->node);
> ...
> mutex_unlock(&rfkill_global_mutex);
> }
>
> The unregister path cannot proceed past rfkill_unregister() until any
> ongoing callback completes. Since device_del() is called after
> rfkill_unregister() returns, no UAF should be possible.
Indeed, that's correct. Please mention this briefly in commit msg. The
same as other ABBA remark in register path.
Best regards,
Krzysztof
prev parent reply other threads:[~2025-12-17 8:57 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-17 5:49 [PATCH] net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write Deepanshu Kartikey
2025-12-17 7:31 ` Krzysztof Kozlowski
2025-12-17 8:11 ` Deepanshu Kartikey
2025-12-17 8:57 ` Krzysztof Kozlowski [this message]
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