From mboxrd@z Thu Jan 1 00:00:00 1970 From: Petr Mladek Subject: Re: [PATCH 25/30] panic, printk: Add console flush parameter and convert panic_print to a notifier Date: Mon, 16 May 2022 16:56:41 +0200 Message-ID: References: <20220427224924.592546-1-gpiccoli@igalia.com> <20220427224924.592546-26-gpiccoli@igalia.com> Mime-Version: 1.0 Return-path: List-Id: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1652713009; 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=oTDrZeo/UdLI29Tuaw8mlcdG/RkPgJLQM7cePAnlqRg=; b=qMST7ia3BcKl3UtC1W2uQ0qkLBJP5Q7YC0oT0Qsb2KbEzU3Or4Q8r5PYsshuphM/GEHsx/ 3TbgfR0/0E5XpsXnd9OyJN2pbUs6sglf0Hs/rZTi2wLDZTO2OOnHvkd7qA4fAmNZA1vdry 3XHA87WfjJ2L5kh4VZznBS1IZ/1m/S0= Content-Disposition: inline In-Reply-To: <20220427224924.592546-26-gpiccoli@igalia.com> Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit 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 19:49:19, Guilherme G. Piccoli wrote: > Currently the parameter "panic_print" relies in a function called > directly on panic path; one of the flags the users can set for > panic_print triggers a console replay mechanism, to show the > entire kernel log buffer (from the beginning) in a panic event. > > Two problems with that: the dual nature of the panic_print > isn't really appropriate, the function was originally meant > to allow users dumping system information on panic events, > and was "overridden" to also force a console flush of the full > kernel log buffer. It also turns the code a bit more complex > and duplicate than it needs to be. > > This patch proposes 2 changes: first, we decouple panic_print > from the console flushing mechanism, in the form of a new kernel > core parameter (panic_console_replay); we kept the functionality > on panic_print to avoid userspace breakage, although we comment > in both code and documentation that this panic_print usage is > deprecated. > > We converted panic_print function to a panic notifier too, adding > it on the panic informational notifier list, executed as the final > callback. This allows a more clear code and makes sense, as > panic_print_sys_info() is really a panic-time only function. > We also moved its code to kernel/printk.c, it seems to make more > sense given it's related to printing stuff. I really like both changes. Just please split it them into two patchset. I mean one patch for the new "panic_console_replay" parameter and 2nd that moves "printk_info" into the notifier. Best Regards, Petr