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 628CC15B10D; Thu, 6 Feb 2025 09:12:24 +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=1738833144; cv=none; b=tbjCnZ596b55eP8q4aTpbsUYgGzurm/ITHlN7RMtF0jWA30djaiuFX6JIhqBNrDB0IrUR623X4xB6OnNoq6mNAhzF7q2+uNwCsrntvUALlBeMUmzDdJZcS9R6TczMhWKu0l/2uQflxyQn/kNnrYnVpbPJxtke3I+9mbBlGt4Mjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738833144; c=relaxed/simple; bh=YMokR+qy7feXtTT7P1mLW6jI3+kd5kyy3YSx0hlrotk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=d97NskdCQBlmw9rpihuT+McxcuElFxklIBgSPt14WojwGPoqPVOCTCQKhXGhxK9xgxiDGd3cGleBFcqnPbQ3bsiVOACDVqE0SyRXuM0/J4ZBrRlTOK9mNFJo42Y+6ojxxrTX3fX379urYEdpeeXQPvD3EdVOc+7NFt6Rab+hhSA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZciL9nxb; 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="ZciL9nxb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 21669C4CEDD; Thu, 6 Feb 2025 09:12:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1738833144; bh=YMokR+qy7feXtTT7P1mLW6jI3+kd5kyy3YSx0hlrotk=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZciL9nxbNtJKUWTHi71y10BV3HwmC2BBfYxd2s7LOQiLKS0jKvMpkwb4XVSTM85mo 4HNH9ruB2C2NJNeYCfmMZbvEF28vumPq/o18xYkD2EGfOk263Ej0wS9Td1NSxdAdr8 /2Kmx3xQkaslinyzVj6UQUMsC1/2lh00RECcSGwcgp8TZ/m93fbSWF7EV0hLjfshF8 tt0j72FRWLOA3tFT9qmtBE3fMpgb2fTqaMeNDbc3uLYb8ZSVQMKXWR2jIaT1mv5U1k GenniY8+GY5Y5hzVyqL8zUQmExr7dFEeQzkgKPfhKTk9mOWyE9D1u+KNqAYqISSShA iJebW1+jomVdQ== Message-ID: Date: Thu, 6 Feb 2025 10:12:21 +0100 Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3][next] tty: tty_buffer: Avoid hundreds of -Wflex-array-member-not-at-end warnings To: "Gustavo A. R. Silva" , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, linux-hardening@vger.kernel.org References: 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: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 06. 02. 25, 4:39, Gustavo A. R. Silva wrote: > Currently, member `sentinel` in `struct tty_bufhead` is causing trouble > becase its type is `struct tty_buffer`, which is a flexible structure > --meaning it contains a flexible-array member. This combined with the > fact that `sentinel` is positioned in the middle of `struct tty_bufhead`, THUMBS_UP > Suggested-by: Greg Kroah-Hartman > Signed-off-by: Gustavo A. R. Silva > --- > Changes in v3: > - Implement `struct tty_buffer_hdr` as a separate struct and embed it > into `struct tty_buffer`. Refactor the rest of the code, accordingly. Better, but: > diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c > index 79f0ff94ce00..cd04a6567a33 100644 > --- a/drivers/tty/tty_buffer.c > +++ b/drivers/tty/tty_buffer.c ... > @@ -576,11 +579,14 @@ int tty_insert_flip_string_and_push_buffer(struct tty_port *port, > void tty_buffer_init(struct tty_port *port) > { > struct tty_bufhead *buf = &port->buf; > + struct tty_buffer *buf_sentinel; > + > + buf_sentinel = container_of(&buf->sentinel, struct tty_buffer, hdr); Bah, so this is ugly and even dangerous if someone adds a member to tty_buffer outside _hdr. We should link headers in the list, it appears. > --- a/include/linux/tty_buffer.h > +++ b/include/linux/tty_buffer.h > @@ -7,7 +7,7 @@ > #include > #include > > -struct tty_buffer { > +struct tty_buffer_hdr { > union { > struct tty_buffer *next; > struct llist_node free; > @@ -15,9 +15,13 @@ struct tty_buffer { > unsigned int used; > unsigned int size; > unsigned int commit; > - unsigned int lookahead; /* Lazy update on recv, can become less than "read" */ > + unsigned int lookahead; /* Lazy update on recv, can become less than "read" */ This is an unrelated/unwanted change. thanks, -- js suse labs