"virsh dump --memory-only --format <compression-type>" command,
where the compression-type is either "kdump-zlib", "kdump-lzo" or
"kdump-snappy". Without the patch, if an x86_64 guest kernel was loaded
with a non-zero "phys_base", the "--machdep phys_base=<offset>" command
line option was required as a workaround or the crash session would fail
with the warning message "WARNING: cannot read linux_banner string"
followed by the fatal error message "crash: vmlinux and <dumpfile name>
do not match!".
(anderson@redhat.com)
the header of compressed kdumps, and the new DUMP_ELF_INCOMPLETE flag
in the header of ELF kdumps. If the makedumpfile(8) facility fails
to complete the creation of compressed or ELF kdump vmcore files
due to ENOSPC or other error, it will mark the vmcore as incomplete.
If either flag is set, the crash utility will issue a warning that
the dumpfile is known to be incomplete during initialization, just
prior to the system banner display. When reads are attempted on
missing data, a read error will be returned. As an alternative,
zero-filled data will be returned if the "--zero_excluded" command
line flag is used, or the "zero_excluded" runtime variable is set
to "on". In either case, the read errors or zero-filled memory
may cause the crash session to fail entirely, cause commands to
fail, or may result in other unpredictable runtime behavior.
(anderson@redhat.com, zhouwj-fnst@cn.fujitsu.com)
either "show" (the default) or "hide". When set to "hide", certain
command output associated with offline cpus will be hidden from view,
and the output will indicate that the cpu is "[OFFLINE]". The new
variable can be set during invocation on the crash command line via
the option "--offline [show|hide]". During runtime, or in a .crashrc
or other crash input file, the variable can be set by entering
"set offline [show|hide]". The commands or options that are affected
when the variable is set to "hide" are as follows:
o On X86_64 machines, the "bt -E" option will not search exception
stacks associated with offline cpus.
o On X86_64 machines, the "mach" command will append "[OFFLINE]"
to the addresses of IRQ and exception stacks associated with
offline cpus.
o On X86_64 machines, the "mach -c" command will not display the
cpuinfo_x86 data structure associated with offline cpus.
o The "help -r" option has been fixed so as to not attempt to
display register sets of offline cpus from ELF kdump vmcores,
compressed kdump vmcores, and ELF kdump clones created by
"virsh dump --memory-only".
o The "bt -c" option will not accept an offline cpu number.
o The "set -c" option will not accept an offline cpu number.
o The "irq -s" option will not display statistics associated with
offline cpus.
o The "timer" command will not display hrtimer data associated
with offline cpus.
o The "timer -r" option will not display hrtimer data associated
with offline cpus.
o The "ptov" command will append "[OFFLINE]" when translating a
per-cpu address offset to a virtal address of an offline cpu.
o The "kmem -o" option will append "[OFFLINE]" to the base per-cpu
virtual address of an offline cpu.
o The "kmem -S" option in CONFIG_SLUB kernels will not display
per-cpu data associated with offline cpus.
o When a per-cpu address reference is passed to the "struct"
command, the data structure will not be displayed for offline
cpus.
o When a per-cpu symbol and cpu reference is passed to the "p"
command, the data will not be displayed for offline cpus.
o When the "ps -[l|m]" option is passed the optional "-C [cpus]"
option, the tasks queued on offline cpus are not shown.
o The "runq" command and the "runq [-t/-m/-g/-d]" options will not
display runqueue data for offline cpus.
o The "ps" command will replace the ">" active task indicator to
a "-" for offline cpus.
The initial system information banner and the "sys" command will
display the total number of cpus as before, but will append the count
of offline cpus. Lastly, a fix has been made for the initialization
time determination of the maximum number of per-cpu objects queued
in a CONFIG_SLAB kmem_cache so as to continue checking all cpus
higher than the first offline cpu. These changes in behavior are not
dependent upon the setting of the crash "offline" variable.
(qiaonuohan@cn.fujitsu.com)
a crash-7.0.4 patch which added per-thread task_struct.rss_stat page
counts to the task's mm_struct.rss_stat page counts in order to show
an accurate/synchronized RSS value. Without the patch, the "ps"
command performance would degrade as the number of tasks increased,
most notably when there were thousands of tasks.
(panfy.fnst@cn.fujitsu.com, anderson@redhat.com)
more "ramdump" files may be entered on the crash command line
in an ordered pair format consisting of the RAM dump filename
and the starting physical address expressed in hexadecimal,
connected with an ampersand:
$ crash vmlinux ramdump@address [ramdump@address]
A temporary ELF header will be created in /var/tmp, and the
combination of the header and the ramdump file(s) will be handled
like a normal ELF vmcore. The ELF header will only exist during
the crash session. If desired, an optional "-o <filename>"
may be entered to create a permanent ELF vmcore file from the
ramdump file(s).
(vinayakm.list@gmail.com, paawan1982@yahoo.com, anderson@redhat.com)
functions from netdump.c and kdump.c via a new read_vmcoreinfo()
method in the global program_context structure. The function
get_log_from_vmcoreinfo() will access vmcoreinfo data via the
new pointer instead of requiring its callers to pass pointers to
their dumpfile-specific function.
(anderson@redhat.com)
The hash queue is used for gathering and verifying lists, and the
original count of 128 may be overwhelmed if a list is extremely
large. For example, on a 256GB system with 192GB of free pages,
the "kmem -f" command takes hours to complete; with this patch,
the time is reduced to a few minutes. In addition, a new command
line option "--hash <count>" has been added to allow a user to
override the default hash queue head count of 32768.
(anderson@redhat.com)
that that are configured with CONFIG_RANDOMIZE_BASE. When set to
"auto", the KASLR relocation value will be determined automatically
by comparing the "_stext" symbol value compiled into the vmlinux file
with the _stext symbol value stored in kdump vmcoreinfo data; on live
systems the comparison will be made with the "_stext" symbol value
that is found in /proc/kallsyms.
(ahonig@google.com, anderson@redhat.com)
X86_64 kernels that are configured with CONFIG_RANDOMIZE_BASE.
The offset value must be equal to the difference between the
symbol values compiled into the vmlinux file and their relocated
value.
(ahonig@google.com, anderson@redhat.com)
