Jun Koi wrote:
Hi,
I found below cmdline params having no documentation anywhere, so
could somebody explain their meaning?
- memory_module
- no_modules
- no_ikconfig
- no_namelist_gzip
- no_kmem_cache
- kmem_cache_delay
- readnow
- buildinfo
- zero_excluded
Many thanks,
J
They're all essentially debug flags for use on kernels/dumpfiles
that for some reason or other would not initialize properly.
memory_module: if /dev/mem or /dev/crash do not suffice you could
force-feed one or the other for live system analysys.
no_modules: if the module initialization code cause crash to
during initialization, skip it with --no_modules.
no_ikconfig: if the reading of the in-kernel config data causes
an initialization-time failure, skip it with --no_ikconfig
no_namelist_gzip: completely obsolete
no_kmem_cache: if the kmem slab cache initialization causes an
initialization-time failure, skip it with --no_kmem_cache
kmem_cache_delay: if the kmem slab cache initialization causes an
initialization-time failure, it can alternatively be delayed
until the first command that accesses the kmem_cache is run
readnow: useless now, but there was a very short period of time
where gcc was creating debuginfo vmlinux files that required
--readnow in order to gather all of the debug data at initialization
time.
buildinfo: dumps information about who/where/when/gcc w/respect to
the crash utility itself.
zero_excluded: if a page was excluded by diskdump or makedumpfile,
it normally returns a failure if the page is accessed. If you
want it to just return a page of zeroes, use --zero_excluded.
In any case, if you find that you need to use any of the flags above,
then it's indicative of (1) a crash utility bug, or (2) a corrupted vmcore.
In either situation, it's best to find and fix the underlying problem
instead of working around it. Using the flags above is only a stop-gap
measure, and should not be "depended upon".
Dave