From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CC8B5271476; Wed, 17 Dec 2025 08:57:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765961871; cv=none; b=ng0pvq53EcMwQ5oVwS2rksKYewJgn7wPtFmC3hSrvZOogadiG1Zetu9PE3GIemXWSEDFtJQuN5rqUaMlMfS3R2i0/vOUiRD70iqbhX3OiSmpE7qpR66fQoWLbnymgjsxWG3ANpSjj5qEd/f87N3Wr1PuscVVE1nZKjYb9Y3967o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765961871; c=relaxed/simple; bh=ui1mP/6A61a/AucY4OUnha5jdOb7H9NDLUh5IXt5UJg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=b6PlN5jc9SVWjZvw5cn6BDwtdYZJ7B0H2i0KgeL8L1ReVQaTgxcY+6Lrds85cBBrBgb2ctDFReAOsOaV6AbAFXkq+bjDgiwU3BYlQj6/wnPApxcC3oAT7nFcvGKmti5HIo3JQPYnQi0BlM0mFAL49Et9lTmsNThotEZ9zhqO6Gc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q8B2rO/z; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q8B2rO/z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66053C4CEFB; Wed, 17 Dec 2025 08:57:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1765961871; bh=ui1mP/6A61a/AucY4OUnha5jdOb7H9NDLUh5IXt5UJg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=q8B2rO/z7b5orerXS4Ffk3ofuOL/WL9lgPbzmUxz3Y+DPn6G4I3gDmKLGjy4fYou4 0XdYQkpdjBdgw/92y9KB9CnUyknQ4NRLC6QHfAOk4SaFuVANhaF8rl1JPZBpga2XIb jrAPNYNGnpfNeB3Zb1iZ6ZmPywp7FZesFAxQs+UDDOmHGM/TAJgtOnZJ02O5EZ2HcA CLr5YNJiBi5EOEdQrSSlTAN1CBABIuct+OZBVXGGF/tW3e/vEOxdUcCYRi2pwG9lfd IjecoyB6AwSTBiYZLE4QzEvaHKwdmF/I8c0QsJUu3kCX1Yn1MNlRBzC2cjeaAvzJGD 6DUwDj/5Wr2YA== Message-ID: <5cb165de-12ef-4e6a-ab8a-aefb53bf9f23@kernel.org> Date: Wed, 17 Dec 2025 09:57:47 +0100 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] net: nfc: fix deadlock between nfc_unregister_device and rfkill_fop_write To: Deepanshu Kartikey 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 References: <20251217054908.178907-1-kartikey406@gmail.com> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit 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