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[157.230.128.187]) by smtp.gmail.com with ESMTPSA id v27sm3350582pfi.61.2020.05.18.09.51.55 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 18 May 2020 09:51:56 -0700 (PDT) Received: by 42.do-not-panic.com (Postfix, from userid 1000) id 17421404B0; Mon, 18 May 2020 16:51:55 +0000 (UTC) Date: Mon, 18 May 2020 16:51:54 +0000 From: Luis Chamberlain To: Johannes Berg Cc: jeyu@kernel.org, akpm@linux-foundation.org, arnd@arndb.de, rostedt@goodmis.org, mingo@redhat.com, aquini@redhat.com, cai@lca.pw, dyoung@redhat.com, bhe@redhat.com, peterz@infradead.org, tglx@linutronix.de, gpiccoli@canonical.com, pmladek@suse.com, tiwai@suse.de, schlad@suse.de, andriy.shevchenko@linux.intel.com, keescook@chromium.org, daniel.vetter@ffwll.ch, will@kernel.org, mchehab+samsung@kernel.org, kvalo@codeaurora.org, davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, ath10k@lists.infradead.org Subject: Re: [PATCH v2 12/15] ath10k: use new module_firmware_crashed() Message-ID: <20200518165154.GH11244@42.do-not-panic.com> References: <20200515212846.1347-1-mcgrof@kernel.org> <20200515212846.1347-13-mcgrof@kernel.org> <2b74a35c726e451b2fab2b5d0d301e80d1f4cdc7.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2b74a35c726e451b2fab2b5d0d301e80d1f4cdc7.camel@sipsolutions.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Sat, May 16, 2020 at 03:24:01PM +0200, Johannes Berg wrote: > On Fri, 2020-05-15 at 21:28 +0000, Luis Chamberlain wrote:> module_firmware_crashed > > You didn't CC me or the wireless list on the rest of the patches, so I'm > replying to a random one, but ... > > What is the point here? > > This should in no way affect the integrity of the system/kernel, for > most devices anyway. Keyword you used here is "most device". And in the worst case, *who* knows what other odd things may happen afterwards. > So what if ath10k's firmware crashes? If there's a driver bug it will > not handle it right (and probably crash, WARN_ON, or something else), > but if the driver is working right then that will not affect the kernel > at all. Sometimes the device can go into a state which requires driver removal and addition to get things back up. > So maybe I can understand that maybe you want an easy way to discover - > per device - that the firmware crashed, but that still doesn't warrant a > complete kernel taint. That is one reason, another is that a taint helps support cases *fast* easily detect if the issue was a firmware crash, instead of scraping logs for driver specific ways to say the firmware has crashed. > Instead of the kernel taint, IMHO you should provide an annotation in > sysfs (or somewhere else) for the *struct device* that had its firmware > crash. It would seem the way some folks are thinking about getting more details would be through devlink. > Or maybe, if it's too complex to walk the entire hierarchy > checking for that, have a uevent, or add the ability for the kernel to > print out elsewhere in debugfs the list of devices that crashed at some > point... All of that is fine, but a kernel taint? debugfs is optional, a taint is simple, and device agnostic. From a support perspective it is very easy to see if a possible issue may be device firmware specific. Luis