Re: [Crash-utility] [PATCH] debuginfo does not pick user_regs_struct on x86_64

----- Original Message ----- >> >> Right -- over the years it has been "found" in some kernel >> version's debuginfo data, but certainly not in all kernel >> versions. (mostly not) >> >> But anyway, its potential non-existence has been worked >> around such that the offset_table entries are not required. >> >> I did test it out on ~150 sample dumpfiles, and while it doesn't >> break anything, it doesn't help either -- the "bt -a" output is >> identical with or without the patch. > > The command "bt -a" can work fine without the patch now, because we > have checked it in get_netdump_regs_x86_64(). > > We have a new hardware to do dump, and use makedumpfile to generate > vmcore. Our hardware can work when the OS is out of controll(for > example: dead loop). When we use crash to analyze the vmcore, bt can > not work, because there is no panic task. > > We have provide the value of register in the vmcore(the format is elf_prstatus, > it is same with normal kdump's vmcore). So I write the code to use the register > from notes in the vmcore when we do not find panic task. So we should know > these offsets. We can check it where we use, but I think it's better to check > and init it in x86_64_init(). Interesting -- so you essentially have an alternative dumping method whose format simulates a kdump. >> >> Did you actually have a situation where a backtrace failed >> without it -- but then worked OK with your patch? >> >> And was there a reason you used "unsigned long long" declarations? >> I understand they are the same, but the kernel uses "unsigned long". >> Why the difference? > > Does this case exist: we build crash on x86 box and use it to analyze the > vmcore which is generate in x86_64 box? If it does not exist, I think > we should use "unsigend long", the same with the kernel. No, that cannot be done. You can build an x86 binary on an x86_64 machine with "make target=X86", but not the other way around. I'll revert them to "unsigned long" declarations, and queue the patch for crash-5.1.3.

Thanks, Dave