From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 96F3A606A330 for ; Wed, 4 Nov 2026 02:49:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=bLPxm6qs; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=cgTxz2yg DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; 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Wed, 4 Nov 2026 02:49:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793760558; bh=ThIbPidvBK4i6Csq/pIkivMxZjIx7r0x4v2l4wVxXBw=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=cgTxz2yghtz136oSvsEgNWxDK1UKzIAz4bUm2ta8Oek1uOr1sjN/JU7idKBzyVbM+ gZPRxn2jAkF+uFEoqh/WGp+va2Gtf6j6EdKSSILE1bZDoBc67WVUqbCPTOzXJM1dPI I8d4vThVTyw5reTsH+tPqHvfmLLjhfq51GCcf4IWcOLbErwBixQ8NXjj8bBFxg/YiJ pxZxxSb7c6tC+orl5EReGxSWQrlG/ZQdai7CpK39WuzwQiHes6P5LMASf9bUnYm29D ZD1E/TdusmxaP1yUZxzL9vGf/mZY8uvoRP0HxfI4ybyclYsndU3plwKUFVepNIWafQ gwZoKEMu5YFag== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH v2 1/5] panic, sys_info: Fix duplicate and dropped all-CPU backtraces in panic To: "Aaron Tomlin" , pmladek@suse.com, john.ogness@linutronix.de, rostedt@goodmis.org, senozhatsky@chromium.org, mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, akpm@linux-foundation.org, baoquan.he@linux.dev, rppt@kernel.org, pasha.tatashin@soleen.com, pratyush@kernel.org, ruirui.yang@linux.dev, david@kernel.org, ljs@kernel.org, liam@infradead.org, vbabka@kernel.org, surenb@google.com, mhocko@suse.com, kees@kernel.org, anna-maria@linutronix.de, frederic@kernel.org, tglx@kernel.org, mhiramat@kernel.org, mathieu.desnoyers@efficios.com, brendan.jackman@linux.dev, hannes@cmpxchg.org, ziy@nvidia.com, bigeasy@linutronix.de, clrkwllms@kernel.org Cc: kexec@lists.infradead.org In-Reply-To: <20261103024453.922373-2-atomlin@atomlin.com> References: <20261103024453.922373-1-atomlin@atomlin.com> <20261103024453.922373-2-atomlin@atomlin.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Wed, 04 Nov 2026 02:49:16 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-10.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > When sys_info() was factored out of kernel/panic.c by > commit b76e89e50fc3 ("panic: generalize panic_print's function to show > sys info"), __sys_info() gained an unconditional call to > trigger_all_cpu_backtrace() when SYS_INFO_ALL_BT is set, while > panic_other_cpus_shutdown() retained its own call to > panic_trigger_all_cpu_backtrace(). >=20 > This causes two problems during a kernel panic: >=20 > 1. vpanic() invokes panic_trigger_all_cpu_backtrace() inside > panic_other_cpus_shutdown() before stopping secondary CPUs, and > then invokes trigger_all_cpu_backtrace() a second time inside > sys_info(panic_print) after secondary CPUs have already been > shut down, stalling for up to 10 seconds waiting for offline > CPUs to respond to NMIs. Furthermore, if SYS_INFO_ALL_BT is > [ ... ] > panic_try_start(), and route SYS_INFO_ALL_BT in __sys_info() > through panic_trigger_all_cpu_backtrace() on the panicking CPU. >=20 > Fixes: b76e89e50fc3 ("panic: generalize panic_print's function to show sy= s info") > Signed-off-by: Aaron Tomlin Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261103024453.9223= 73-1-atomlin@atomlin.com?part=3D1