Re: /var/log/messages doesn't have crash info when kernel gets panic/oops/crash

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Hi,
I have experimented few things and results are below.
Case 1) echo 0 > /proc/sys/kernel/panic_on_oops        When BUG/oops occurred it is able to log the diagnostics to /var/log/messages        and then continue(not switching to dump-saving kernel).
        What I am looking is - I want both the things to be happen.        that is - it should log the appropriate messages in /var/log/messsages and        should be able to take kernel dump.
case 2) In general, When panic has occurred we won't log any type of messages in        /var/log/messages ... am I right ?        If KEXEC is enabled and dump-saving kernel is loaded then         will switch to it and save the kernel dump.
        I have added the dump_stack() function call in the panic() function         before calling crash_kexec with few seconds of delay. It is behaving         like randomly (ie. some time stack traces are logged in /var/log/messages and         not for rest of the time)
        What I am looking is - I want to log the  appropriate messages in /var/log/messages        and then switch to dump-saving kernel.
case 3) In general, When die/nmi_die called we used to log the appropriate messages in /var/log/message        and then saving kernel dump will be depends on KEXEC enable and loading dump-saving kernel.        --- am I right ?                I have added the delay in die() function with few seconds before calling crash_kexec()        But I never seen messages logged in /var/log/messages, I can see those on serial console.
        Here also my intention is want both, ie. log the appropriate messages in /var/log/messages        and then take the action as per KEXEC enabled.


Please advice me, What we can do to achieve those things.
Thanks for helping me here.

regards,Seetharam




> -----Original Message-----> From: nhorman@xxxxxxxxxx> Sent: Sat, 13 Jun 2009 14:07:36 -0400> To: dseetharam@xxxxxxxxx> Subject: Re: /var/log/messages doesn't have crash info when kernel gets> panic/oops/crash> > On Fri, Jun 12, 2009 at 11:01:35PM -0800, Dharmosoth Seetharam wrote:>> >> Hi Neil,>> >> Thanks for your quick reply.>> >> What you have suggested is nice when we got/save crash dump (i.e vmcore)>> What if we failed to save/capture vmcore info or vmcore is corrupted>> etc. then we dont get any information>> regarding the panic/crash/oops at anywhere?>> > If the vmcore is corrupted to the point where makedumpfile can't extract> the> dmesg log, then its certain that syslog wouldn't have been able to write> anything to /var/log/messages either.  As a last resort you can try run> strings> on the corrupted vmcore and see if the dmesg log is still in there> somewhere.> > If you forgot to capture the vmcore, theres not much more help I can give> you,> Im afraid.  You'll just have to make sure you capture it next time.  If> you only> need the backtrace, and don't want the rest of the vmcore, you can make> kdump> just run makedumpfile --dump-dmesg /proc/vmcore /var/log/oops.txt> > Neil> 

>> >> >> >> Thanks and Regards>> >>  Seetharam>> >> >>> -----Original Message----->>> From: nhorman@xxxxxxxxxx>>> Sent: Fri, 12 Jun 2009 16:05:13 -0400>>> To: dseetharam@xxxxxxxxx>>> Subject: Re: /var/log/messages doesn't have crash info when kernel gets>>> panic/oops/crash>>> >>> On Fri, Jun 12, 2009 at 01:25:49AM -0800, Dharmosoth Seetharam wrote:>>>> Hi,>>>> >>>> I have encounter a problem called /var/log/messages does not contain>>>> any>>>> information>>>> on kernel crash dump.>>>> >>>> Prior to enabling KEXEC we saw stack traces and bug info etc in>>>> /var/log/messages.>>>> After enabling KEXEC feature those info was missed.>>>> >>>> How can we get those missed info in /var/log/messages even when KEXEC>>>> feature is enabled.>>>> >>>> Any help will appreciate.>>>> >>> run crash on the resultant vmcore file that kexec can produce/save and>>> get the>>> dmesg log out of it.>>> alternatively you can use makedumpfile with the --dump-dmesg log>>> >>> Neil>>> >>>> >>>> Thanks and Regards>>>> Seetharam>>>> >>>> ____________________________________________________________>>>> Receive Notifications of Incoming Messages>>>> Easily monitor multiple email accounts & access them with a click.>>>> Visit http://www.inbox.com/notifier and check it out!>>>> >>>> _______________________________________________>>>> kexec mailing list>>>> kexec@xxxxxxxxxxxxxxxxxxx>>>> http://lists.infradead.org/mailman/listinfo/kexec>> >> ____________________________________________________________>> GET FREE SMILEYS FOR YOUR IM & EMAIL - Learn more at>> http://www.inbox.com/smileys>> Works with AIM®, MSN® Messenger, Yahoo!® Messenger, ICQ®, Google Talk™>> and most webmails_______________________________________________fastboot mailing listfastboot@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.linux-foundation.org/mailman/listinfo/fastboot


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