From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C3A4DC54ED1 for ; Tue, 27 May 2025 16:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=UZYLROFC13QWr0WtIHITpKv2k/IYMUKl/Ik95XSzStc=; b=PmeXeYt0UH0V5LkOOe+W+g4kEL 3pHoOKvo5klPRrtUB2z/GUGzsUDKw2qfHFcBDsRmmIjlDAN7Xc2pA5QXJxl7m9YQDe/fg5O4K3GyE 8dM90OXTm1yN+GtghXHzatQNCk9LHpFm9bDuqIc/Nr//ItxJpjqBxARfefQbmUk7ky8iNtFiBuAUU bfO0CpRWTWfvelRHy/j8jkBB3W97uLdyrgOnPLuKDSpHwh+rIAL/CLuPXwtfCkjdW6lzgRs/KcoDM TqxNTXGzk+c+pJ8ByFgkSPh+zSxnJ+r7aTHxqOaxg5QB9KKZFA35CA8YtkmzVza3/eDoItr5WNji1 un7/M/ew==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1uJxF0-0000000BAWk-1GNN; Tue, 27 May 2025 16:33:26 +0000 Received: from relay3-d.mail.gandi.net ([2001:4b98:dc4:8::223]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1uJxCp-0000000BADE-1BT2 for linux-arm-kernel@lists.infradead.org; Tue, 27 May 2025 16:31:13 +0000 Received: by mail.gandi.net (Postfix) with ESMTPSA id 538A81FCF2; Tue, 27 May 2025 16:31:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1748363469; 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: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=UZYLROFC13QWr0WtIHITpKv2k/IYMUKl/Ik95XSzStc=; b=IhRDeJrS9jEMuIKBecnBJriiCigzhovdLdAo8PcxOnxSCbLHAg2pE5zE5zYVmw1R4+039U CK8W6lC0U0n5puU297QfUE5VkxhETbk9T+KybDCrRlalPEUgCI6a0740UOxd5Sbwd3cSL2 mYH8HJ8au6B/lR5hCQcIYrJhJye69OOHxk3cD3dKL0RXz7SNYbNHAEaaoAxe5DOl+XHiNp hu2gde3xzMIE+FeM8/T8HK4PBLAbR+2FWXws0XHzYk8mKOP1L7b/Qv0aa9Dm4dU5Z6Me3B 0gtdejge1087acIokX/hgKqRFBJKeJRrdTYh4v+2O5SPx6Mj07/+3K8M5YqlMg== Date: Tue, 27 May 2025 18:31:05 +0200 From: Maxime Chevallier To: Alexis =?UTF-8?B?TG90aG9yw6k=?= Cc: Alexandre Torgue , Jose Abreu , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , Richard Cochran , Phil Reid , Thomas Petazzoni , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] net: stmmac: add explicit check and error on invalid PTP clock rate Message-ID: <20250527183105.7c4bad49@device-24.home> In-Reply-To: <20250527-stmmac_tstamp_div-v2-1-663251b3b542@bootlin.com> References: <20250527-stmmac_tstamp_div-v2-1-663251b3b542@bootlin.com> Organization: Bootlin X-Mailer: Claws Mail 4.3.1 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-State: clean X-GND-Score: -100 X-GND-Cause: gggruggvucftvghtrhhoucdtuddrgeeffedrtddtgddvtdekieculddtuddrgeefvddrtddtmdcutefuodetggdotefrodftvfcurfhrohhfihhlvgemucfitefpfffkpdcuggftfghnshhusghstghrihgsvgenuceurghilhhouhhtmecufedtudenucesvcftvggtihhpihgvnhhtshculddquddttddmnecujfgurhepfffhvfevuffkjghfohfogggtgfesthhqredtredtjeenucfhrhhomhepofgrgihimhgvucevhhgvvhgrlhhlihgvrhcuoehmrgigihhmvgdrtghhvghvrghllhhivghrsegsohhothhlihhnrdgtohhmqeenucggtffrrghtthgvrhhnpeekheegieejkeetfffhleehteffgefhfffhueefieefffejfeethfevudetudeuueenucffohhmrghinhepkhgvrhhnvghlrdhorhhgnecukfhppeeltddrjeeirdeivddrudejudenucevlhhushhtvghrufhiiigvpedtnecurfgrrhgrmhepihhnvghtpeeltddrjeeirdeivddrudejuddphhgvlhhopeguvghvihgtvgdqvdegrdhhohhmvgdpmhgrihhlfhhrohhmpehmrgigihhmvgdrtghhvghvrghllhhivghrsegsohhothhlihhnrdgtohhmpdhnsggprhgtphhtthhopeduiedprhgtphhtthhopegrlhgvgihishdrlhhothhhohhrvgessghoohhtlhhinhdrtghomhdprhgtphhtthhopegrlhgvgigrnhgurhgvrdhtohhrghhuvgesfhhoshhsrdhsthdrtghomhdprhgtphhtthhopehjohgrsghrvghusehshihnohhpshihshdrtghomhdprhgtphhtt hhopegrnhgurhgvfidonhgvthguvghvsehluhhnnhdrtghhpdhrtghpthhtohepuggrvhgvmhesuggrvhgvmhhlohhfthdrnhgvthdprhgtphhtthhopegvughumhgriigvthesghhoohhglhgvrdgtohhmpdhrtghpthhtohepkhhusggrsehkvghrnhgvlhdrohhrghdprhgtphhtthhopehprggsvghnihesrhgvughhrghtrdgtohhm X-GND-Sasl: maxime.chevallier@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250527_093111_829082_3EC1AE09 X-CRM114-Status: GOOD ( 23.69 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Alexis, On Tue, 27 May 2025 08:33:44 +0200 Alexis Lothor=C3=A9 wrote: > The stmmac platform drivers that do not open-code the clk_ptp_rate value > after having retrieved the default one from the device-tree can end up > with 0 in clk_ptp_rate (as clk_get_rate can return 0). It will > eventually propagate up to PTP initialization when bringing up the > interface, leading to a divide by 0: >=20 > Division by zero in kernel. > CPU: 1 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.30-00001-g48313bd5= 768a #22 > Hardware name: STM32 (Device Tree Support) > Call trace: > unwind_backtrace from show_stack+0x18/0x1c > show_stack from dump_stack_lvl+0x6c/0x8c > dump_stack_lvl from Ldiv0_64+0x8/0x18 > Ldiv0_64 from stmmac_init_tstamp_counter+0x190/0x1a4 > stmmac_init_tstamp_counter from stmmac_hw_setup+0xc1c/0x111c > stmmac_hw_setup from __stmmac_open+0x18c/0x434 > __stmmac_open from stmmac_open+0x3c/0xbc > stmmac_open from __dev_open+0xf4/0x1ac > __dev_open from __dev_change_flags+0x1cc/0x224 > __dev_change_flags from dev_change_flags+0x24/0x60 > dev_change_flags from ip_auto_config+0x2e8/0x11a0 > ip_auto_config from do_one_initcall+0x84/0x33c > do_one_initcall from kernel_init_freeable+0x1b8/0x214 > kernel_init_freeable from kernel_init+0x24/0x140 > kernel_init from ret_from_fork+0x14/0x28 > Exception stack(0xe0815fb0 to 0xe0815ff8) >=20 > Prevent this division by 0 by adding an explicit check and error log > about the actual issue. >=20 > Fixes: 19d857c9038e ("stmmac: Fix calculations for ptp counters when cloc= k input =3D 50Mhz.") > Signed-off-by: Alexis Lothor=C3=A9 > --- > Changes in v2: > - Add Fixes tag > - Reword commit message to clarify the triggering cause of the issue > - Link to v1: https://lore.kernel.org/r/20250523-stmmac_tstamp_div-v1-1-b= ca8a5a3a477@bootlin.com > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +++++ > 1 file changed, 5 insertions(+) >=20 > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/= net/ethernet/stmicro/stmmac/stmmac_main.c > index 918d7f2e8ba992208d7d6521a1e9dba01086058f..f68e3ece919cc88d0bf199a39= 4bc7e44b5dee095 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -835,6 +835,11 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *p= riv, u32 systime_flags) > if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp)) > return -EOPNOTSUPP; > =20 > + if (!priv->plat->clk_ptp_rate) { > + netdev_err(priv->dev, "Invalid PTP clock rate"); > + return -EINVAL; > + } > + > stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags); > priv->systime_flags =3D systime_flags; This may be some nitpick that can be addressed at a later point, but we now have a guarantee that when stmmac_ptp_register() gets called, priv->ptp_clk_rate is non-zero, right ? If so, we can drop the test in said function : if (priv->plat->has_gmac4 && priv->plat->clk_ptp_rate) priv->plat->cdc_error_adj =3D (2 * NSEC_PER_SEC) / priv->plat->clk_ptp_ra= te; There is another spot in the code, like in the EST handling, where we divide by priv->plat->ptp_clk_rate : stmmac_adjust_time(...) stmmac_est_configure(priv, priv, priv->est, priv->plat->clk_ptp_rate) .est_configure() ctrl |=3D ((NSEC_PER_SEC / ptp_rate) [...] Maybe we should fail EST configuration as well if ptp_clk_rate is 0 (probably in stmmac_tc.c's tc_taprio_configure or in the .est_configure). That can be a step for later as well, as I don't know if the setup you found this bug on even supports taprio/EST, and setups that do didn't seem to encounter the bug yet. Besides all that, Reviewed-by: Maxime Chevallier Thanks, Maxime