From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=194.13.80.246 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794470895; b=3AzIedsY1PbUHinuRvtQorLTbRDJp6IxnrO5bVU724FJ73YPuWr37hi3soZLWwdO31FW ng+GAqmwpOkxhDZl0/cYyp3q611XaKDbwowkU2EzZE+Bz3lze52nyTlgMsuM0WL9pA0Xk Goif7v4BiGvc88ksEZW1dSQy/YQrmcuDpdOMxVFTWZ6pfEQ7D6+3Fi/tzNsEUk/6AzbNO V7pxYcWEWxA3saWc06EfUBucxMamhJLZd88RgkEp8DyxDcCKZMjpD4ZvcVO/TXbg9tJBw 9Dlnp27D5Ma4XIAR1hPtNOt7d4PXkysH9pPRJISuXqTvvfmwxJksgnBmuZH2Fl8eY2w== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794470895; h=DMARC-Filter:Received:DKIM-Signature:MIME-Version:Date:From:To:Cc: Subject:In-Reply-To:References:Message-ID:X-Sender:Content-Type: Content-Transfer-Encoding:X-Last-TLS-Session-Version; bh=I6xLghz5H9I+4KRL0++50cP7pz5F4KKwdpL8TpdIoH8=; b=daw03eZIWlaaVVDOBDiLx6pf2kIt1jr4BXWK3KyJsWSWelXvTBYr57ATfokBN2JcJGQ/ e9/IFqX7RCDwz7Ag6kJqkdma1MFhbNPu1AppbfwFGEZkuih7/xETCAxRY4/9m4/t/wU8p pYdvBj721WMnkwHlo77pWwW1ZTZJMKECIouR4MkYzQejdwhWdrHHK6XqT+0Bd8faU2i7z xrBHu8alD10fEVI1MkV+Kko49vJVI8rAYfbM2G2u9y4Zwyn3rA4HWYbUsrzyQ8/FGrX3p 9lXfKpbVDrkGuWjPVYXifA9c7n/ryL+AjWuHgtIfENW7CWFeH/P+HJJSDIoA+xIwNkA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none header.from=tipi-net.de; spf=pass smtp.mailfrom=tipi-net.de; dkim=pass header.d=tipi-net.de header.i=@tipi-net.de header.a=rsa-sha256 header.s=dkim header.b=jlpTw++h; arc=none smtp.remote-ip=194.13.80.246 Received: from mail.tipi-net.de (mail.tipi-net.de [194.13.80.246]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1848D606A327 for ; Thu, 12 Nov 2026 08:08:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 1848D606A327 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=tipi-net.de header.i=@tipi-net.de header.a=rsa-sha256 header.s=dkim header.b=jlpTw++h Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id A9606A1675; Thu, 12 Nov 2026 09:08:00 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tipi-net.de; s=dkim; t=1794470885; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=I6xLghz5H9I+4KRL0++50cP7pz5F4KKwdpL8TpdIoH8=; b=jlpTw++hrDxhhvu4ks0ockODMgBcFMoDa1eRm46nLmI8WmJYPPIjNZ6YvSXrXIRs/hC0dw qgfsNEcu/2PwSeRuDxjSCNC04KqloT+Ry8k2PWKrwnh1t4hWxu1d5vw8AB2qygCI7+vVRW omr2fFx2Dkmj65R71U323fUcdTFCUYLzgyRyIt0W/vNortPN3WkZV8DCqiMvR17VaxyrYk t1BXIQM08TDyHQHJZGzSGKaH8vpdctY8nGx9fBbeuzIZFKgz6Yy3JUJe4/PJDBVaTDQcqx vB6xnB0gWHfBsOorcPUo9nvhBJxrLVQeShI7lqGP1QHvIFPPviQa0TsbweUzXA== X-Mailing-List: linux-serial@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Date: Thu, 12 Nov 2026 09:08:00 +0100 From: Nicolai Buchwitz To: Dan Carpenter Cc: Russell King , Greg Kroah-Hartman , Jiri Slaby , Kartik Rajput , Fan Wu , Frank Li , Karl Mehltretter , =?UTF-8?Q?Stefan_D=C3=B6singer?= , linux-serial@vger.kernel.org Subject: Re: [PATCH] serial: amba-pl011: Fix divide by zero in pl011_console_get_options() In-Reply-To: <6fdea544b2fb8f4226e296a952331cd42684474d.1794315353.git.dan@cryspen.com> References: <6fdea544b2fb8f4226e296a952331cd42684474d.1794315353.git.dan@cryspen.com> Message-ID: <3726053453c5abac97e4fe90bf40d205@tipi-net.de> X-Sender: nb@tipi-net.de Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi Dan On 11.11.2026 10:23, Dan Carpenter wrote: > When you boot QEMU with -kernel and don't set a baud rate the ibrd and > fbrd values are zero and so clkdiv is also zero. It results in a > divide > by zero. Most of the time people don't notice because on > qemu-system-arm64 when you divide by zero the result is zero and > everything works. However, if you enable UBSAN, then the divide by > zero > leads to a crash and the boot fails. > > Return early when clkdev is zero. This leaves the baud rate set to its nit: clkdiv > default value of 38400. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Cc: stable@vger.kernel.org > Signed-off-by: Dan Carpenter > [...] Reviewed-by: Nicolai Buchwitz Thanks, Nicolai