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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 8CBCBC61DD8 for ; Sat, 14 Nov 2020 06:52:23 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3F9ED20678 for ; Sat, 14 Nov 2020 06:52:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="OtFGwxpu" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3F9ED20678 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B03166B005D; Sat, 14 Nov 2020 01:52:22 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id A89EC6B0093; Sat, 14 Nov 2020 01:52:22 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9C5976B0095; Sat, 14 Nov 2020 01:52:22 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0218.hostedemail.com [216.40.44.218]) by kanga.kvack.org (Postfix) with ESMTP id 6D3EF6B005D for ; Sat, 14 Nov 2020 01:52:22 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 234573620 for ; Sat, 14 Nov 2020 06:52:22 +0000 (UTC) X-FDA: 77482104924.23.love87_510e18727315 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin23.hostedemail.com (Postfix) with ESMTP id 083A037606 for ; Sat, 14 Nov 2020 06:52:22 +0000 (UTC) X-HE-Tag: love87_510e18727315 X-Filterd-Recvd-Size: 4842 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf22.hostedemail.com (Postfix) with ESMTP for ; Sat, 14 Nov 2020 06:52:21 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 6BC932073C; Sat, 14 Nov 2020 06:52:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605336740; bh=ObAOBqZNtreQ5iTbc4vp4rnvs0bMjsVLb9Qrf9oukh4=; h=Date:From:To:Subject:In-Reply-To:From; b=OtFGwxpuQZ95UjewASbhRR+QpV2gJUWg2Nc/Y8XqrL4Jfq5XYwMJ02bojprnh3TFb /ocu5xemGHKlsK1oXRD8s+RNpCCSMdXeQBP3K+uhWZjQzr1o+Q7xHTWB8sAYktjtKe f8D5ihRaNQScjwTj1CduMmcBzh+NFin1Yq7hQ2cM= Date: Fri, 13 Nov 2020 22:52:20 -0800 From: Andrew Morton To: aik@ozlabs.ru, akpm@linux-foundation.org, christophe.leroy@csgroup.eu, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, wangkefeng.wang@huawei.com Subject: [patch 13/14] panic: don't dump stack twice on warn Message-ID: <20201114065220._M2ijwOkQ%akpm@linux-foundation.org> In-Reply-To: <20201113225115.b24faebc85f710d5aff55aa7@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Christophe Leroy Subject: panic: don't dump stack twice on warn Before commit 3f388f28639f ("panic: dump registers on panic_on_warn"), __warn() was calling show_regs() when regs was not NULL, and show_stack() otherwise. After that commit, show_stack() is called regardless of whether show_regs() has been called or not, leading to duplicated Call Trace: [ 7.112617] ------------[ cut here ]------------ [ 7.117041] WARNING: CPU: 0 PID: 1 at arch/powerpc/mm/nohash/8xx.c:186 mmu_mark_initmem_nx+0x24/0x94 [ 7.126021] CPU: 0 PID: 1 Comm: swapper Not tainted 5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty #4092 [ 7.135202] NIP: c00128b4 LR: c0010228 CTR: 00000000 [ 7.140205] REGS: c9023e40 TRAP: 0700 Not tainted (5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty) [ 7.149131] MSR: 00029032 CR: 24000424 XER: 00000000 [ 7.155760] [ 7.155760] GPR00: c0010228 c9023ef8 c2100000 0074c000 ffffffff 00000000 c2151000 c07b3880 [ 7.155760] GPR08: ff000900 0074c000 c8000000 c33b53a8 24000822 00000000 c0003a20 00000000 [ 7.155760] GPR16: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 [ 7.155760] GPR24: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00800000 [ 7.191092] NIP [c00128b4] mmu_mark_initmem_nx+0x24/0x94 [ 7.196333] LR [c0010228] free_initmem+0x20/0x58 [ 7.200855] Call Trace: [ 7.203319] [c9023f18] [c0010228] free_initmem+0x20/0x58 [ 7.208564] [c9023f28] [c0003a3c] kernel_init+0x1c/0x114 [ 7.213813] [c9023f38] [c000f184] ret_from_kernel_thread+0x14/0x1c [ 7.219869] Instruction dump: [ 7.222805] 7d291850 7d234b78 4e800020 9421ffe0 7c0802a6 bfc10018 3fe0c060 3bff0000 [ 7.230462] 3fff4080 3bffffff 90010024 57ff0010 <0fe00000> 392001cd 7c3e0b78 953e0008 [ 7.238327] CPU: 0 PID: 1 Comm: swapper Not tainted 5.10.0-rc2-s3k-dev-01375-gf46ec0d3ecbd-dirty #4092 [ 7.247500] Call Trace: [ 7.249977] [c9023dc0] [c001e070] __warn+0x8c/0xd8 (unreliable) [ 7.255815] [c9023de0] [c05e0e5c] report_bug+0x11c/0x154 [ 7.261085] [c9023e10] [c0009ea4] program_check_exception+0x1dc/0x6e0 [ 7.267430] [c9023e30] [c000f43c] ret_from_except_full+0x0/0x4 [ 7.273238] --- interrupt: 700 at mmu_mark_initmem_nx+0x24/0x94 [ 7.273238] LR = free_initmem+0x20/0x58 [ 7.283155] [c9023ef8] [00000000] 0x0 (unreliable) [ 7.287913] [c9023f18] [c0010228] free_initmem+0x20/0x58 [ 7.293160] [c9023f28] [c0003a3c] kernel_init+0x1c/0x114 [ 7.298410] [c9023f38] [c000f184] ret_from_kernel_thread+0x14/0x1c [ 7.304479] ---[ end trace 31702cd2a9570752 ]--- Only call show_stack() when regs is NULL. Link: https://lkml.kernel.org/r/e8c055458b080707f1bc1a98ff8bea79d0cec445.1604748361.git.christophe.leroy@csgroup.eu Fixes: 3f388f28639f ("panic: dump registers on panic_on_warn") Signed-off-by: Christophe Leroy Cc: Alexey Kardashevskiy Cc: Kefeng Wang Signed-off-by: Andrew Morton --- kernel/panic.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/kernel/panic.c~panic-dont-dump-stack-twice-on-warn +++ a/kernel/panic.c @@ -605,7 +605,8 @@ void __warn(const char *file, int line, panic("panic_on_warn set ...\n"); } - dump_stack(); + if (!regs) + dump_stack(); print_irqtrace_events(current); _