From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-y-209.mailbox.org (mout-y-209.mailbox.org [91.198.250.237]) (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 CF32617A2FB; Mon, 22 Sep 2025 12:47:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.198.250.237 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758545253; cv=none; b=Ce+YWYAlUgVa2m9sC/TDn5OEtTsufEmHfGdNqjJAY0U7BSiEKWY8MJVXE6NOyKmoW4ntef9pWX8ndaIFDn/36OM0DkwG/mejS12DnY5BPmqzHX7IKF8qWxanyUpb+jzArbElEWypC7n2R6BQ/8GYEqV4iZxOXqNrWwA1ZB4SulM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1758545253; c=relaxed/simple; bh=woqjYdr6fYQ/tq8XxibmlyTyVlBuByAOdKiPLXjTrtU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=k/qw1py6Tvm0PrKWkakNWWviwpkJDcD4arZw47IC5TWYRuzG0/eYlJd0Mdvu/y98R2JxFdvTw2Sdc1R52+7lOaLBaKYeEeWHIoRU6R9K6igWcXj9a16SDrcb9q5ApuMJ0giWxIeSaRkF1MzppCgX8mbRlF/plt+s/mkr61yLcBM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mssola.com; spf=fail smtp.mailfrom=mssola.com; dkim=pass (2048-bit key) header.d=mssola.com header.i=@mssola.com header.b=kKc01khb; arc=none smtp.client-ip=91.198.250.237 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=mssola.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=mssola.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mssola.com header.i=@mssola.com header.b="kKc01khb" Received: from smtp1.mailbox.org (smtp1.mailbox.org [10.196.197.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-y-209.mailbox.org (Postfix) with ESMTPS id 4cVjYd1j2wz9yXX; Mon, 22 Sep 2025 14:47:17 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mssola.com; s=MBO0001; t=1758545237; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=woqjYdr6fYQ/tq8XxibmlyTyVlBuByAOdKiPLXjTrtU=; b=kKc01khbIUo4IyTASFpsTzwS2a0hqdnJQ1I4eD7VW9+1/0IpIq0k22/CTIjntgf7GiwiQX 6mH6HXb35vRzGtH6/s9jz49amQ2USEMmmzjwzg1QST5d2fCR+cFB3c9viwtoPJhdR5SO1b onH0taTuBtjwHFvYreTHsUFSu2TOCU+MdPIEMr6e8r7mWk4RS0AWIjEIKZ13pKMGOE3w4Q JPxTBlIRbPqlCUopIG1qT3uAwX+RpQ2N7DNIGUAqS6NWTRDnum19IRalNToe+LryCLZoJF HTkzPt1gNAvFT6RbyloDZzqLuWjWCBc12kV7TRP0P4sofru6likGiHBIJNNWgQ== From: =?utf-8?Q?Miquel_Sabat=C3=A9_Sol=C3=A0?= To: David Sterba Cc: linux-btrfs@vger.kernel.org, clm@fb.com, dsterba@suse.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/2] btrfs: Prevent open-coded arithmetic in kmalloc In-Reply-To: <20250922102850.GL5333@twin.jikos.cz> (David Sterba's message of "Mon, 22 Sep 2025 12:28:50 +0200") References: <20250919145816.959845-1-mssola@mssola.com> <20250919145816.959845-2-mssola@mssola.com> <20250922102850.GL5333@twin.jikos.cz> Date: Mon, 22 Sep 2025 14:47:13 +0200 Message-ID: <87h5wu4pta.fsf@> Precedence: bulk X-Mailing-List: linux-btrfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Hello, David Sterba @ 2025-09-22 12:28 +02: > On Fri, Sep 19, 2025 at 04:58:15PM +0200, Miquel Sabat=C3=A9 Sol=C3=A0 wr= ote: >> As pointed out in the documentation, calling 'kmalloc' with open-coded >> arithmetic can lead to unfortunate overflows and this particular way of >> using it has been deprecated. Instead, it's preferred to use >> 'kmalloc_array' in cases where it might apply so an overflow check is >> performed. > > So this is an API cleanup and it makes sense to use the checked > multiplication but it should be also said that this is not fixing any > overflow because in all cases the multipliers are bounded small numbers > derived from number of items in leaves/nodes. Yes, it's just an API cleanup and I don't think it fixes any current bug in the code base. So no need to CC stable or anything like that. > >> Signed-off-by: Miquel Sabat=C3=A9 Sol=C3=A0 > > Reviewed-by: David Sterba Thanks for the review! 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