[RFC][PATCH 1/3] Embed vmcoreinfo into kernel file
vgoyal at in.ibm.com
Fri Aug 17 08:28:03 EDT 2007
On Fri, Aug 17, 2007 at 03:43:31PM +0900, Ken'ichi Ohmichi wrote:
> >- There is another important field which I would like to see in vmcoreinfo
> > and that is time of crash (lets say CRASH_TIME). This will indicate the
> > timestamp when did system actually crash. One can read the time in
> > crash_kexec(), fill in the field and then save vmcore info note.
> > For this, either you need to scan the vmcoreinfo note again and fill in
> > the time stamp. Or you need to do vmcoreinfo note saving after crash
> > instead of boot time.
> Is it necessary of the field for timestamp ?
> The crash utility can display the time of crash already like the following.
> # crash vmlinux vmcore
> KERNEL: vmlinux
> DUMPFILE: vmcore
> CPUS: 2
> DATE: Tue Jul 10 20:41:50 2007 <- Here
> UPTIME: 00:04:58
> LOAD AVERAGE: 0.12, 0.22, 0.11
> TASKS: 88
> NODENAME: peak
> RELEASE: 184.108.40.206-0.12-default
> VERSION: #1 SMP Thu May 17 14:00:09 UTC 2007
> MACHINE: ia64 (1000 Mhz)
> MEMORY: 5.5 GB
> PANIC: "SysRq : Trigger a crashdump"
> PID: 3455
> COMMAND: "bash"
> TASK: e0000040f2f40000 [THREAD_INFO: e0000040f2f410d0]
> CPU: 0
> STATE: TASK_RUNNING (SYSRQ)
But this requires a debug compiled vmlinux to be available on the system
and that's a rarity. For example, we are exporting UTSNAME also which
can be retrieved by opening vmcore with crash.
By exporting this, now one can write a small utility in second kernel,
which can just look at the /proc/vmcore in second kernel, determine that
machine had crashed and send a notification over network to other machine
with crash time stamp.
> +#define SYMBOL(name) \
> + vmcoreinfo_append_str("SYMBOL(%s)=%lx\n", #name, (unsigned long)&name)
> +#define SIZE(name) \
> + vmcoreinfo_append_str("SIZE(%s)=%d\n", #name, sizeof(struct name))
> +#define OFFSET(name, field) \
> + vmcoreinfo_append_str("OFFSET(%s.%s)=%d\n", #name, #field, &(((struct name *)0)->field))
> +#define LENGTH(name, value) \
> + vmcoreinfo_append_str("LENGTH(%s)=%d\n", #name, value)
> +#define CONFIG(name) \
> + vmcoreinfo_append_str("CONFIG_%s=%c\n", #name, CONFIG_##name)
Have you tested CONFIG(). For me it did not work? Are you getting output
like CONFIG_KEXEC=y with above macro?
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