From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Mladek Subject: Re: [PATCH 20/30] panic: Add the panic informational notifier list Date: Mon, 16 May 2022 16:11:06 +0200 Message-ID: References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-21-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: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=8ARg9pmpq4WYUln1h89e8PyizC+ws8syAxTjgJ/s9eQ=; b=38Q4F7vItL/aQt ffazl+MbDJxwROB+HofbsUIZVTd9cY4GRUNdOd3IQ6+34UyvXJ/L6PnjiCGcpWFUIsT2SsQurqe6Z uK5AIm5ha8VdI/YX2gIFlndzwgcrvGrDYc6Ws/BQfj0+D+SOS7qXJoWDaO7GsaUj5+lgMNDhbs5bW eqE7UDXDWDfNdVIDATXcusp+Mk3kShk6j1u1lyPWacKneb1lEbizAo+BTEI/soVtxwaap6UPycMLl RJRXj41G7hjOhBMa6zMqmrlwQ151Czu2WYQ9EItj38d+Y9yrheTMj6EMvdmB52iseVj31CDGB9BXg J+l+a9CPU8Ce+Tth79Fw==; DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652710268; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=dmHPB9vjv1LBmNrF4zaonBMXasUoClA4XRHwK4fdG3Q=; b=uHHoYScC3vOzAq1rF/GezErIJTTCAnG26YueVBaMYGI4KIiBuE4CJEi5I5FkSHuHNJvOhi jBbeahpPdNTqQb9qWzy8wQwtiwj/B2njZ1Svs0P1iMsaZXkpVlpc6Bgj/6IAHlnD6RNRY+ 7obFqakfVm+qw0H2R1BXYJwwfwabCHA= Content-Disposition: inline In-Reply-To: <20220427224924.592546-21-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: "Guilherme G. Piccoli" Cc: akpm@linux-foundation.org, bhe@redhat.com, kexec@lists.infradead.org, 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, kernel@gpiccoli.net, halves@canonical.com, fabiomirmar@gmail.com, alejandro.j.jimenez@oracle.com, andriy.shev On Wed 2022-04-27 19:49:14, Guilherme G. Piccoli wrote: > The goal of this new panic notifier is to allow its users to > register callbacks to run earlier in the panic path than they > currently do. This aims at informational mechanisms, like dumping > kernel offsets and showing device error data (in case it's simple > registers reading, for example) as well as mechanisms to disable > log flooding (like hung_task detector / RCU warnings) and the > tracing dump_on_oops (when enabled). > > Any (non-invasive) information that should be provided before > kmsg_dump() as well as log flooding preventing code should fit > here, as long it offers relatively low risk for kdump. > > For now, the patch is almost a no-op, although it changes a bit > the ordering in which some panic notifiers are executed - specially > affected by this are the notifiers responsible for disabling the > hung_task detector / RCU warnings, which now run first. In a > subsequent patch, the panic path will be refactored, then the > panic informational notifiers will effectively run earlier, > before ksmg_dump() (and usually before kdump as well). > > We also defer documenting it all properly in the subsequent > refactor patch. Finally, while at it, we removed some useless > header inclusions too. > > Signed-off-by: Guilherme G. Piccoli All notifiers moved in this patch seems to fit well the "info" notifier list. The patch looks good from this POV. I still have to review the rest of the patches to see if it is complete. Best Regards, Petr