From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Guilherme G. Piccoli" Subject: [PATCH 27/30] powerpc: Do not force all panic notifiers to execute before kdump Date: Wed, 27 Apr 2022 19:49:21 -0300 Message-ID: <20220427224924.592546-28-gpiccoli@igalia.com> References: <20220427224924.592546-1-gpiccoli@igalia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: 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:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=anFDFlu0bsCOXNr2IgAtKg5GaPR/PV6lDnUPtLXtsK8=; b=ZtJFqSfOY1cqQi weIGml9EsEcjU9WbB/kVX5PlkjB3Z0NX2ydCyTMSL0WAjvCs3cB7zi8d1uk5R1/XrYmFjQk08w4PG jjIsBxx79fMWCIUv5wIExNmg9DVjd07AP2nZqh9CAzqJlFXkMm6d/tNzJsCzM0epVlRufAHEoEWCI ASLwle7SHQmSkvrZcplS4/i8uMhJKn1WTImBZL61lyoiicWslSF0OlyAQ+jxivPnJ2fkPvqZSZwpd d4ZpvBLdqNJ0L2GdMIJ6pBuQ1Q0jBGtJT8235X5TNCtS1VJ8RjYxs9P1VSryx5l3stQQ48Ww8lElP x/J5MYKgZPFJclVlCofQ==; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To:Content-Type:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=C9iT/xJ8gF8J/f7SmqQO2c8pu+KvBPlFfkqGdYboS2I=; b=PMFgjQG40D4y0EE10+nqxAPHVI yNLZ1EZJdP0IH30iYafdBfM788VaINOAVfe8Gnevld0DclzQJRd8t+br/vJapdawGOEWHQTLdmHei 1IQvYGZ//MLpN+QQDVtOXWSfDQyyspNE1J3gOgOC4NUam3dGx8JeBgJ9jpYRHFoaP71Y3fG1ERN+7 JvwIb059Xf3lNBTrEP8JiyuPOh5ugwSvNao5NfaR+bMPV8BospKPkEU02jshVAtp1UBbOdjrRb2r2 ze90RIwfaZigyOQntmQCmXs163wt4gsMUWHmf1nSoidLeEjFKj9WA7H531Eyz4iqvzof4LvLiIP9u dq8Lxg9g==; In-Reply-To: <20220427224924.592546-1-gpiccoli@igalia.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-um" Errors-To: linux-um-bounces+glud-user-mode-linux-devel=m.gmane-mx.org@lists.infradead.org To: akpm@linux-foundation.org, bhe@redhat.com, pmladek@suse.com, kexec@lists.infradead.org Cc: linux-kernel@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, coresight@lists.linaro.org, linuxppc-dev@lists.ozlabs.org, linux-alpha@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-leds@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-pm@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, linux-tegra@vger.kernel.org, linux-um@lists.infradead.org, linux-xtensa@linux-xtensa.org, netdev@vger.kernel.org, openipmi-developer@lists.sourceforge.net, rcu@vger.kernel.org, sparclinux@vger.kernel.org, xen-devel@lists.xenproject.org, x86@kernel.org, kernel-dev@igalia.com, gpiccoli@igalia.com, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shevchenko@linux.intel.com, arnd@arndb.de, bp@alien8. Commit 06e629c25daa ("powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic") introduced a hardcoded setting of kernel parameter "crash_kexec_post_notifiers", effectively forcing all the panic notifiers to execute earlier in the panic path, before kdump. The reason for that was a fadump issue on collecting data accurately, due to smp_send_stop() setting all CPUs offline, so the net effect desired with this change was to avoid calling the regular CPU shutdown function, and instead rely on crash_smp_send_stop(), which copes fine with fadump. The collateral effect was to increase the risk for kdump if fadump is not used, since it forces all panic notifiers to execute early, before kdump. Happens that, after a panic refactor, crash_smp_send_stop() is now used by default in the panic path, so there is no reason to mess with the notifiers ordering (which was also improved in the refactor) from within arch code. Fixes: 06e629c25daa ("powerpc/fadump: Fix inaccurate CPU state info in vmcore generated with panic") Cc: Benjamin Herrenschmidt Cc: Hari Bathini Cc: Michael Ellerman Cc: Nicholas Piggin Cc: Paul Mackerras Signed-off-by: Guilherme G. Piccoli --- We'd like to thanks specially the MiniCloud infrastructure [0] maintainers, that allow us to test PowerPC code in a very complete, functional and FREE environment. [0] https://openpower.ic.unicamp.br/minicloud arch/powerpc/kernel/fadump.c | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c index 65562c4a0a69..35ae8c09af66 100644 --- a/arch/powerpc/kernel/fadump.c +++ b/arch/powerpc/kernel/fadump.c @@ -1649,14 +1649,6 @@ int __init setup_fadump(void) register_fadump(); } - /* - * In case of panic, fadump is triggered via ppc_panic_event() - * panic notifier. Setting crash_kexec_post_notifiers to 'true' - * lets panic() function take crash friendly path before panic - * notifiers are invoked. - */ - crash_kexec_post_notifiers = true; - return 1; } /* -- 2.36.0