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 X-Spam-Level: X-Spam-Status: No, score=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 346C9C47087 for ; Fri, 28 May 2021 05:41:50 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id DC3FC613BA for ; Fri, 28 May 2021 05:41:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DC3FC613BA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=atomide.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: 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=ksFH5gf1LWeBIiFPAIPtFyj9ooyrGRD1eS4jTQvCUvc=; b=LllhZIbVMf6n2z gT5ZaIqXS9lLZ/l/ibkXkMWyMVKLqKX5XSsU+hhzmAEpylxNwEveM/o9vAQ1sP32SPJh8CrYEIQ3r 6d6v6HnCepCVvi+MfVeoxrhzI/J2twUVAMhQEGMt/9cWFSr/tuJgX26nU/RyYjwtx7Qp3b6FkCXaQ tEsAttBgEKnVP0BXR+shtGxkqxr2DCcVYu1mZNFOWoJUq7MfSor0TCuaskmXN7mZ4NXpw9G50gBx8 E/Yx3DFZFUy++21L7VXMbXiCZnBJZs8z/DqdjU1uIgIfdVbhqaG5OOaI497lpCOdeltAUnAE/zLHm RtDomKCd+XaXILD6XzLA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lmVEL-00CKDY-Ck; Fri, 28 May 2021 05:40:21 +0000 Received: from desiato.infradead.org ([90.155.92.199]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lmVEJ-00CKCd-Kq for linux-arm-kernel@bombadil.infradead.org; Fri, 28 May 2021 05:40:19 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=cETaThobFlxsDrRNrmeRsUyofv6797thPp6heUdldZo=; b=EDKxntaJFgvMqTfw4s3Vdtnj/0 egDD3qy7ub9BkA7BRu+Af9OIsrGGxAwNVOO/g3YBMYAE3Qar89SE9e40Uwjncc1Cq3zBzVAUCUOjr LujQehtMmtV+BNgXqu1XOqVJPXGMHKwXl4JkVPbW1/LM9bEnluKzoqKE0ALkQkacscKw7wHpQ+peB 6Fl7O+IaNiwa+TUDEwD7imAPPbgR/Ej8X9b873hlLi5WpAV69gfUByUCafiE6E5l7SPIeR1fCBYrW wKindB0uSjH2crtbeMt27vhZuSIdm5ddwGQuYYy8oXu2INXVaz80rWKRkkUUkB0uH8Sf1XfaOe4vf Lx+cBnYg==; Received: from muru.com ([72.249.23.125]) by desiato.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lmVE5-001ErI-Or for linux-arm-kernel@lists.infradead.org; Fri, 28 May 2021 05:40:14 +0000 Received: from atomide.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTPS id 4F1B380A8; Fri, 28 May 2021 05:40:00 +0000 (UTC) Date: Fri, 28 May 2021 08:39:51 +0300 From: Tony Lindgren To: Greg Kroah-Hartman Cc: Vignesh Raghavendra , Jiri Slaby , Jan Kiszka , linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, Linux ARM Mailing List , linux-kernel@vger.kernel.org Subject: Re: [PATCH] serial: 8250: 8250_omap: Fix possible interrupt storm Message-ID: References: <20210511151955.28071-1-vigneshr@ti.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210528_064012_770820_7AA8BD34 X-CRM114-Status: GOOD ( 18.28 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Greg, Vignesh & Jan, * Greg Kroah-Hartman [210513 14:17]: > On Tue, May 11, 2021 at 08:49:55PM +0530, Vignesh Raghavendra wrote: > > It is possible that RX TIMEOUT is signalled after RX FIFO has been > > drained, in which case a dummy read of RX FIFO is required to clear RX > > TIMEOUT condition. Otherwise, RX TIMEOUT condition is not cleared > > leading to an interrupt storm > > > > Cc: stable@vger.kernel.org > > How far back does this need to go? What commit id does this fix? What > caused this to just show up now vs. previously? I just noticed this causes the following regression in Linux next when pressing a key on uart console after boot at least on omap3. This seems to happen on serial_port_in(port, UART_RX) in the quirk handling. Vignesh, it seems this quirk needs some soc specific flag added to it maybe? Or maybe UART_OMAP_RX_LVL register is not available for all the SoCs? I think it's best to drop this patch until the issues are resolved, also there are some open comments above that might be answered by limiting this quirk to a specific range of SoCs :) Regards, Tony 8< ------------------------ #regzb introduced: 31fae7c8b18c ("serial: 8250: 8250_omap: Fix possible interrupt storm") Internal error: : 1028 [#1] SMP ARM Modules linked in: CPU: 0 PID: 870 Comm: syslog Not tainted 5.13.0-rc3-next-20210527-00001-g9b545469a50f #34 Hardware name: Generic OMAP36xx (Flattened Device Tree) PC is at mem_serial_in+0xc/0x20 LR is at omap8250_irq+0x258/0x2d4 pc : [] lr : [] psr: 60000193 sp : c2975c90 ip : 00000000 fp : c1836000 r10: c0ff7f20 r9 : c0ff7f40 r8 : 00000058 r7 : c2975ce0 r6 : 00000000 r5 : 00000001 r4 : c1031a24 r3 : fa06a000 r2 : 00000002 r1 : 00000000 r0 : c1031a24 Flags: nZCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none Control: 10c5387d Table: 829cc019 DAC: 00000051 Register r0 information: non-slab/vmalloc memory Register r1 information: NULL pointer Register r2 information: non-paged memory Register r3 information: 0-page vmalloc region starting at 0xfa000000 allocated at iotable_init+0x0/0xf4 Register r4 information: non-slab/vmalloc memory Register r5 information: non-paged memory Register r6 information: NULL pointer Register r7 information: non-slab/vmalloc memory Register r8 information: non-paged memory Register r9 information: non-slab/vmalloc memory Register r10 information: non-slab/vmalloc memory Register r11 information: slab kmalloc-256 start c1836000 pointer offset 0 size 256 Register r12 information: NULL pointer Process syslog (pid: 870, stack limit = 0x64988e4e) ... [] (mem_serial_in) from [] (omap8250_irq+0x258/0x2d4) [] (omap8250_irq) from [] (__handle_irq_event_percpu+0x58/0x1f0) [] (__handle_irq_event_percpu) from [] (handle_irq_event+0x68/0xcc) [] (handle_irq_event) from [] (handle_level_irq+0xc4/0x1c8) [] (handle_level_irq) from [] (__handle_domain_irq+0x84/0xfc) [] (__handle_domain_irq) from [] (__irq_svc+0x6c/0x90) Exception stack(0xc2975d28 to 0xc2975d70) 5d20: c2532990 c25328a8 00000006 c289a015 c2532888 c2532990 5d40: 00000002 00000000 00000006 64407df7 c2532880 64407df7 00000006 c2975d78 5d60: c02ef31c c030097c 60000013 ffffffff [] (__irq_svc) from [] (__d_lookup_rcu+0xbc/0x1b8) [] (__d_lookup_rcu) from [] (lookup_fast+0x48/0x180) [] (lookup_fast) from [] (walk_component+0x3c/0x1c8) [] (walk_component) from [] (link_path_walk.part.0+0x23c/0x364) [] (link_path_walk.part.0) from [] (path_parentat+0x34/0x74) [] (path_parentat) from [] (filename_parentat+0x88/0x19c) [] (filename_parentat) from [] (filename_create+0x44/0x150) [] (filename_create) from [] (do_mkdirat+0x58/0x11c) [] (do_mkdirat) from [] (ret_fast_syscall+0x0/0x58) _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel