From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 5700C3D7D88; Fri, 31 Jul 2026 08:32:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785486760; cv=none; b=rECvSTQxQ4/LY4ANebYEmckgFn8Yfp1PLZewJCbulDt3Abt2BJY8HltdkEULHfATjmf1d5+mIm7abQc5gya5jsq0njjum4nSN7xRtMDoF6MvLoMtuOHvypeVOQOSB6Jz28UrJvnZ8Zrtw+9zs7luRfn9WeCLPQezO3+FzHckyZs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785486760; c=relaxed/simple; bh=n0BRJe5zh203HsVANA71itkRuE7rCo+oHlfC5ad3v5k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sSlxuREBnFJaVxPQD6KJYtkCMe5hK4db38kyUsMFZbDSuOnPrBdyia8pZUgInHUCFNCZ3OHJvZg7QlAtC6ZvNqkm+/NzhMV1dMa2LLs1S7Q070JPt1psB2W9ZecZKgY+r2dYTwlvY4bHn+sQTX9NnGhdxi9HS0WcicGDMEfXKh4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GTCLud3U; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GTCLud3U" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B64961F000E9; Fri, 31 Jul 2026 08:32:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785486759; bh=tgmH+dPIlumP0Ze5ndGHCpKCcld/uG34oGoxDHYHkIs=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=GTCLud3UodOosN1TedE+JNZ+pjkVdLqImWFRB2GaCJLLOGiNaTodSFZt1YUbG77AC FJhy6hilsUSwpV+s2LUJHhtxdUdyT+Js9DDThtrjypx8EiR23Air3NP3Ic49dafsO+ TtY45wWGWf2eQfPJkUd6X41KqRwDkF2t7gH6bCbxfItAj/GydOgA+rf9H8Eb2gB/eE 5vm0ItFXw7bl5jt9Ll6bSKAhfGnAQ/OH4uZE04MU/grq1kiAbQo5anaNrnONRKr/2c 4dijra+C1sRXupGbO5LiW24dGuhOP8stJidh/Nn1nI70QjWT8uQDd0k03h0+AQ0HBT BpwQyZ/4sM2TA== Message-ID: Date: Fri, 31 Jul 2026 10:32:36 +0200 Precedence: bulk X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] tty: vcc: hold port lock when clearing tty pointer in vcc_cleanup To: Greg Kroah-Hartman , sparclinux@vger.kernel.org Cc: "David S. Miller" , Joshua Rogers , linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, stable References: <20260731-aisle-tty-vcc-v1-0-962e18beb8a8@linuxfoundation.org> <20260731-aisle-tty-vcc-v1-2-962e18beb8a8@linuxfoundation.org> Content-Language: en-US From: Jiri Slaby Autocrypt: addr=jirislaby@kernel.org; keydata= xsFNBE6S54YBEACzzjLwDUbU5elY4GTg/NdotjA0jyyJtYI86wdKraekbNE0bC4zV+ryvH4j rrcDwGs6tFVrAHvdHeIdI07s1iIx5R/ndcHwt4fvI8CL5PzPmn5J+h0WERR5rFprRh6axhOk rSD5CwQl19fm4AJCS6A9GJtOoiLpWn2/IbogPc71jQVrupZYYx51rAaHZ0D2KYK/uhfc6neJ i0WqPlbtIlIrpvWxckucNu6ZwXjFY0f3qIRg3Vqh5QxPkojGsq9tXVFVLEkSVz6FoqCHrUTx wr+aw6qqQVgvT/McQtsI0S66uIkQjzPUrgAEtWUv76rM4ekqL9stHyvTGw0Fjsualwb0Gwdx ReTZzMgheAyoy/umIOKrSEpWouVoBt5FFSZUyjuDdlPPYyPav+hpI6ggmCTld3u2hyiHji2H cDpcLM2LMhlHBipu80s9anNeZhCANDhbC5E+NZmuwgzHBcan8WC7xsPXPaiZSIm7TKaVoOcL 9tE5aN3jQmIlrT7ZUX52Ff/hSdx/JKDP3YMNtt4B0cH6ejIjtqTd+Ge8sSttsnNM0CQUkXps w98jwz+Lxw/bKMr3NSnnFpUZaxwji3BC9vYyxKMAwNelBCHEgS/OAa3EJoTfuYOK6wT6nadm YqYjwYbZE5V/SwzMbpWu7Jwlvuwyfo5mh7w5iMfnZE+vHFwp/wARAQABzSFKaXJpIFNsYWJ5 IDxqaXJpc2xhYnlAa2VybmVsLm9yZz7CwXcEEwEIACEFAlW3RUwCGwMFCwkIBwIGFQgJCgsC BBYCAwECHgECF4AACgkQvSWxBAa0cEnVTg//TQpdIAr8Tn0VAeUjdVIH9XCFw+cPSU+zMSCH eCZoA/N6gitEcnvHoFVVM7b3hK2HgoFUNbmYC0RdcSc80pOF5gCnACSP9XWHGWzeKCARRcQR 4s5YD8I4VV5hqXcKo2DFAtIOVbHDW+0okOzcecdasCakUTr7s2fXz97uuoc2gIBB7bmHUGAH XQXHvdnCLjDjR+eJN+zrtbqZKYSfj89s/ZHn5Slug6w8qOPT1sVNGG+eWPlc5s7XYhT9z66E l5C0rG35JE4PhC+tl7BaE5IwjJlBMHf/cMJxNHAYoQ1hWQCKOfMDQ6bsEr++kGUCbHkrEFwD UVA72iLnnnlZCMevwE4hc0zVhseWhPc/KMYObU1sDGqaCesRLkE3tiE7X2cikmj/qH0CoMWe gjnwnQ2qVJcaPSzJ4QITvchEQ+tbuVAyvn9H+9MkdT7b7b2OaqYsUP8rn/2k1Td5zknUz7iF oJ0Z9wPTl6tDfF8phaMIPISYrhceVOIoL+rWfaikhBulZTIT5ihieY9nQOw6vhOfWkYvv0Dl o4GRnb2ybPQpfEs7WtetOsUgiUbfljTgILFw3CsPW8JESOGQc0Pv8ieznIighqPPFz9g+zSu Ss/rpcsqag5n9rQp/H3WW5zKUpeYcKGaPDp/vSUovMcjp8USIhzBBrmI7UWAtuedG9prjqfO wU0ETpLnhgEQAM+cDWLL+Wvc9cLhA2OXZ/gMmu7NbYKjfth1UyOuBd5emIO+d4RfFM02XFTI t4MxwhAryhsKQQcA4iQNldkbyeviYrPKWjLTjRXT5cD2lpWzr+Jx7mX7InV5JOz1Qq+P+nJW YIBjUKhI03ux89p58CYil24Zpyn2F5cX7U+inY8lJIBwLPBnc9Z0An/DVnUOD+0wIcYVnZAK DiIXODkGqTg3fhZwbbi+KAhtHPFM2fGw2VTUf62IHzV+eBSnamzPOBc1XsJYKRo3FHNeLuS8 f4wUe7bWb9O66PPFK/RkeqNX6akkFBf9VfrZ1rTEKAyJ2uqf1EI1olYnENk4+00IBa+BavGQ 8UW9dGW3nbPrfuOV5UUvbnsSQwj67pSdrBQqilr5N/5H9z7VCDQ0dhuJNtvDSlTf2iUFBqgk 3smln31PUYiVPrMP0V4ja0i9qtO/TB01rTfTyXTRtqz53qO5dGsYiliJO5aUmh8swVpotgK4 /57h3zGsaXO9PGgnnAdqeKVITaFTLY1ISg+Ptb4KoliiOjrBMmQUSJVtkUXMrCMCeuPDGHo7 39Xc75lcHlGuM3yEB//htKjyprbLeLf1y4xPyTeeF5zg/0ztRZNKZicgEmxyUNBHHnBKHQxz 1j+mzH0HjZZtXjGu2KLJ18G07q0fpz2ZPk2D53Ww39VNI/J9ABEBAAHCwV8EGAECAAkFAk6S 54YCGwwACgkQvSWxBAa0cEk3tRAAgO+DFpbyIa4RlnfpcW17AfnpZi9VR5+zr496n2jH/1ld wRO/S+QNSA8qdABqMb9WI4BNaoANgcg0AS429Mq0taaWKkAjkkGAT7mD1Q5PiLr06Y/+Kzdr 90eUVneqM2TUQQbK+Kh7JwmGVrRGNqQrDk+gRNvKnGwFNeTkTKtJ0P8jYd7P1gZb9Fwj9YLx jhn/sVIhNmEBLBoI7PL+9fbILqJPHgAwW35rpnq4f/EYTykbk1sa13Tav6btJ+4QOgbcezWI wZ5w/JVfEJW9JXp3BFAVzRQ5nVrrLDAJZ8Y5ioWcm99JtSIIxXxt9FJaGc1Bgsi5K/+dyTKL wLMJgiBzbVx8G+fCJJ9YtlNOPWhbKPlrQ8+AY52Aagi9WNhe6XfJdh5g6ptiOILm330mkR4g W6nEgZVyIyTq3ekOuruftWL99qpP5zi+eNrMmLRQx9iecDNgFr342R9bTDlb1TLuRb+/tJ98 f/bIWIr0cqQmqQ33FgRhrG1+Xml6UXyJ2jExmlO8JljuOGeXYh6ZkIEyzqzffzBLXZCujlYQ DFXpyMNVJ2ZwPmX2mWEoYuaBU0JN7wM+/zWgOf2zRwhEuD3A2cO2PxoiIfyUEfB9SSmffaK/ S4xXoB6wvGENZ85Hg37C7WDNdaAt6Xh2uQIly5grkgvWppkNy4ZHxE+jeNsU7tg= In-Reply-To: <20260731-aisle-tty-vcc-v1-2-962e18beb8a8@linuxfoundation.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 31. 07. 26, 10:15, Greg Kroah-Hartman wrote: > From: Joshua Rogers > > vcc_cleanup() sets port->tty to NULL without holding port->lock, racing > with vcc_event() LDC callbacks that read port->tty under port->lock and > then use tty->port. This can cause a use-after-free when the callback > dereferences tty->port after cleanup has already destroyed and freed it. > > Assisted-by: AISLE:Snapshot > Cc: stable > Signed-off-by: Joshua Rogers > Signed-off-by: Greg Kroah-Hartman > --- > drivers/tty/vcc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/tty/vcc.c b/drivers/tty/vcc.c > index 3947bd2b75ac..03ed8c692acd 100644 > --- a/drivers/tty/vcc.c > +++ b/drivers/tty/vcc.c > @@ -983,10 +983,13 @@ static int vcc_install(struct tty_driver *driver, struct tty_struct *tty) > static void vcc_cleanup(struct tty_struct *tty) > { > struct vcc_port *port; > + unsigned long flags; > > port = vcc_get(tty->index, true); > if (port) { > + spin_lock_irqsave(&port->lock, flags); > port->tty = NULL; > + spin_unlock_irqrestore(&port->lock, flags); For these, I like scope_guard(spinlock_irqsave, &port->lock) port->tty = NULL; more, as well. thanks, -- js suse labs