Messages in this thread | | | Date | Wed, 17 Nov 2010 12:45:18 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 0/2] kmsg_dump: adding to reboot, halt, poweroff and emergency_restart path |
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On Wed, 17 Nov 2010 09:58:18 -0500 Seiji Aguchi <seiji.aguchi@hds.com> wrote:
> Hi, > > This series aims to develop logging facility for enterprise use. > > It is important to save kernel messages reliably on enterprise system > because they are helpful for diagnosing system. > > This series add kmsg_dump() to the paths loosing kernel messages. > The use case is the following. > > [Use case of reboot/poweroff/halt/emergency_restart] > > My company has often experienced the followings in our support service. > - Customer's system suddenly reboots. > - Customers ask us to investigate the reason of the reboot. > > We recognize the fact itself because boot messages remain in /var/log/messages. > However, we can't investigate the reason why the system rebooted, because the last messages don't remain. > And off course we can't explain the reason. > > > We can solve above problem with this patch as follows. > Case1: reboot with command > - We can see "Restarting system with command:" or ""Restarting system.". > > Case2: halt with command > - We can see "System halted.". > > Case3: poweroff with command > - We can see " Power down.". > > Case4: emergency_restart with sysrq. > - We can see "Sysrq:" outputted in __handle_sysrq(). > > Case5: emergency_restart with softdog. > - We can see "Initiating system reboot" in watchdog_fire(). > > So, we can distinguish the reason of reboot, poweroff, halt and emergency_restart. > > If customer executed reboot command, you may think the customer should know the fact. > However, they often claim they don't execute the command when they rebooted system by mistake. > > No evidential message remain on current Linux kernel, so we can't show the proof to the customer. > This patch improves this situation. > > > The first patch alters mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC, > KMSG_DUMP_OOPS and KMSG_DUMP_KEXEC because they would like to log crashes only. > > The latter patch adds kmsg_dump() to reboot, halt, poweroff and emergency_restart path.
Damn, that's a good changelog. We can actually understand why you wrote the patch, and see what its value is!
One thing: please don't send multiple patches with the same title. See Documentation/SubmittingPatches section 15. I renamed these two patches to
kmsg_dump: constrain mtdoops and ramoops to perform their actions only for KMSG_DUMP_PANIC
and
kmsg_dump: add kmsg_dump() calls to the reboot, halt, poweroff and emergency_restart paths
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