Openmoko Bug #2135: write kernel crash message somewhere where it can be retrieved after reboot?

Openmoko Public Trac bugs at docs.openmoko.org
Wed Nov 26 13:39:25 CET 2008


#2135: write kernel crash message somewhere where it can be retrieved after
reboot?
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 Reporter:  lindi            |          Owner:  openmoko-kernel
     Type:  enhancement      |         Status:  new            
 Priority:  normal           |      Milestone:                 
Component:  System Software  |        Version:  unspecified    
 Severity:  normal           |       Keywords:                 
 Haspatch:  0                |      Blockedby:                 
Estimated:                   |    Patchreview:                 
 Blocking:                   |   Reproducible:                 
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Comment(by andy):

 For folks lucky enough to have a debug board, this isn't needed since you
 can just look in your terminal emulator and see the full backtrace or
 whatever.  But I agree if you don't have that then it is very tough to
 know what the hell happened.  It does not seem we can expect our devices
 to give access to the debug console in a user friendly way (ie, private
 USB connector for it) for foreseeable future unfortunately.

 In the Linux x86 world there's a trick thing to store stuff in RTC RAM for
 debugging suspend for example, but it's very ugly.

 Definitely this isn't the business of the bootloader to deal with.  But I
 agree about using RAM.

 We can use physical address at end of RAM, we could back off the 128MB we
 tell Linux about a little.  Next Linux boot can display it, we can
 probably expose it to userspace and let initscript handle it, since we
 only target case where panic could not be seen on original boot due to X
 for example.  If a panic is happening during boot shortly we will display
 it on LCM by default in Qi case.

 It should be pretty certain that you can always boot into backup rootfs /
 kernel unless something awful has happened, even then you can nuke your SD
 Card and come back like that with high certainty.

-- 
Ticket URL: <https://docs.openmoko.org/trac/ticket/2135#comment:2>
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