Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
Dharmosoth Seetharam dseetha...@inbox.com writes: 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. You can't have it. Sorry. Keeping user space alive is something that simply can not be done reliably. Please advice me, What we can do to achieve those things. The only scenario I see possible is to take the dump. Use makedumpfile or the crash log command to extract the kernel messages and put them in the /var/log/messages. Eric ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
Dharmosoth Seetharam dseetha...@inbox.com writes: 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. You can't have it. Sorry. Keeping user space alive is something that simply can not be done reliably. Please advice me, What we can do to achieve those things. The only scenario I see possible is to take the dump. Use makedumpfile or the crash log command to extract the kernel messages and put them in the /var/log/messages. Eric ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
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: nhor...@redhat.com Sent: Sat, 13 Jun 2009 14:07:36 -0400 To: dseetha...@inbox.com 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: nhor...@redhat.com Sent: Fri, 12 Jun 2009 16:05:13 -0400 To: dseetha...@inbox.com 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 ke...@lists.infradead.org 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 list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
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? Thanks and Regards Seetharam -Original Message- From: nhor...@redhat.com Sent: Fri, 12 Jun 2009 16:05:13 -0400 To: dseetha...@inbox.com 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 ke...@lists.infradead.org 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 list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
-Original Message- From: ebied...@xmission.com Sent: Sat, 13 Jun 2009 00:11:25 -0700 To: dseetha...@inbox.com Subject: Re: /var/log/messages doesn't have crash info when kernel gets panic/oops/crash Dharmosoth Seetharam dseetha...@inbox.com writes: 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? Hi Eric, Basic questions. 1) Do you have panic on oops set? I think that setting more than anything else will be the difference in what shows up in /var/log/messages. Yes, in my case panic_on_oops was set with 1 2) Have you tried a dry run and confirmed you can get a crash dump? No, I haven't tried this. 3) Are you using kvm kvm? kernel virtual memory? thanks, Seetharam Eric Thanks and Regards Seetharam -Original Message- From: nhor...@redhat.com Sent: Fri, 12 Jun 2009 16:05:13 -0400 To: dseetha...@inbox.com 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 ke...@lists.infradead.org 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 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! ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
-Original Message- From: ebied...@xmission.com Sent: Sat, 13 Jun 2009 05:51:25 -0700 To: dseetha...@inbox.com Subject: Re: /var/log/messages doesn't have crash info when kernel gets panic/oops/crash Dharmosoth Seetharam dseetha...@inbox.com writes: -Original Message- From: ebied...@xmission.com Sent: Sat, 13 Jun 2009 00:11:25 -0700 To: dseetha...@inbox.com Subject: Re: /var/log/messages doesn't have crash info when kernel gets panic/oops/crash Dharmosoth Seetharam dseetha...@inbox.com writes: 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? Hi Eric, Basic questions. 1) Do you have panic on oops set? I think that setting more than anything else will be the difference in what shows up in /var/log/messages. Yes, in my case panic_on_oops was set with 1 That is the reason thing don't show up in /var/log/messages because you panic before syslog has a chance to write the messages. Thanks. So, if panic_on_oops set with 0(default), we will get all the needed info like stack traces, bug info etc. in /var/log/messages then reboots. Or do we need to apply any specific patches to get info in /var/log/messages? 2) Have you tried a dry run and confirmed you can get a crash dump? No, I haven't tried this. It sounds like you have not been getting the coredumps when problems happen. Running a simple test run to Alt-sysrq-c to confirm that things are basically setup ok is a good idea. Sorry, I misunderstood your question. I have gave dry run and confirmed that the dumps are getting saved in particular dir and able to analyze. I did in both the ways like 1 - echo c /proc/sysrq-trigger 2 -Alt -sysrq -c thanks, Seetharam 3) Are you using kvm kvm? kernel virtual memory? Kernel virtual machine. In particular. Hardware acceleration for virtual machines. Eric FREE ONLINE PHOTOSHARING - Share your photos online with your friends and family! Visit http://www.inbox.com/photosharing to find out more! ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
Dharmosoth Seetharam dseetha...@inbox.com writes: Basic questions. 1) Do you have panic on oops set? I think that setting more than anything else will be the difference in what shows up in /var/log/messages. Yes, in my case panic_on_oops was set with 1 That is the reason thing don't show up in /var/log/messages because you panic before syslog has a chance to write the messages. Thanks. So, if panic_on_oops set with 0(default), we will get all the needed info like stack traces, bug info etc. in /var/log/messages then reboots. Or do we need to apply any specific patches to get info in /var/log/messages? 2) Have you tried a dry run and confirmed you can get a crash dump? No, I haven't tried this. It sounds like you have not been getting the coredumps when problems happen. Running a simple test run to Alt-sysrq-c to confirm that things are basically setup ok is a good idea. Sorry, I misunderstood your question. I have gave dry run and confirmed that the dumps are getting saved in particular dir and able to analyze. I did in both the ways like 1 - echo c /proc/sysrq-trigger 2 -Alt -sysrq -c Then unless you are having problems capturing core dumps in real failure situations it sounds like all is well with the world. A kernel oops is normally not fatal and the kernel tries to limp along allowing for better diagnostics etc. This allows klogd to read the kernels message buffer and pass the kernel messages to syslog which writes the messages to /var/log/messages. After a kernel panic nothing is allowed to happen which prevents user space from writing to /var/log/messages in the usual way. If you want data in /var/log/messages it appears you have two choices. 1) Post process a core dump as Neil suggested and feed the kernel log buffer to syslog. 2) disable panic on oops. The system will continue to limp along allowing user space to write to /var/log/messages. Eric ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
Re: [Fastboot] /var/log/messages doesn't have crash info when kernel gets panic/oops/crash
-Original Message- From: ebied...@xmission.com Sent: Sat, 13 Jun 2009 07:08:50 -0700 To: dseetha...@inbox.com Subject: Re: /var/log/messages doesn't have crash info when kernel gets panic/oops/crash Dharmosoth Seetharam dseetha...@inbox.com writes: Basic questions. 1) Do you have panic on oops set? I think that setting more than anything else will be the difference in what shows up in /var/log/messages. Yes, in my case panic_on_oops was set with 1 That is the reason thing don't show up in /var/log/messages because you panic before syslog has a chance to write the messages. Thanks. So, if panic_on_oops set with 0(default), we will get all the needed info like stack traces, bug info etc. in /var/log/messages then reboots. Or do we need to apply any specific patches to get info in /var/log/messages? 2) Have you tried a dry run and confirmed you can get a crash dump? No, I haven't tried this. It sounds like you have not been getting the coredumps when problems happen. Running a simple test run to Alt-sysrq-c to confirm that things are basically setup ok is a good idea. Sorry, I misunderstood your question. I have gave dry run and confirmed that the dumps are getting saved in particular dir and able to analyze. I did in both the ways like 1 - echo c /proc/sysrq-trigger 2 -Alt -sysrq -c Then unless you are having problems capturing core dumps in real failure situations it sounds like all is well with the world. A kernel oops is normally not fatal and the kernel tries to limp along allowing for better diagnostics etc. This allows klogd to read the kernels message buffer and pass the kernel messages to syslog which writes the messages to /var/log/messages. After a kernel panic nothing is allowed to happen which prevents user space from writing to /var/log/messages in the usual way. If you want data in /var/log/messages it appears you have two choices. 1) Post process a core dump as Neil suggested and feed the kernel log buffer to syslog. 2) disable panic on oops. The system will continue to limp along allowing user space to write to /var/log/messages. Eric Thanks Eric. I will try all the ways as you suggested and let you know the outcome. regards, Seetharam FREE ONLINE PHOTOSHARING - Share your photos online with your friends and family! Visit http://www.inbox.com/photosharing to find out more! ___ fastboot mailing list fastboot@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/fastboot
