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Old 02-10-2011, 07:28 PM
Dave Anderson
Default crash version 5.1.2 is available

- Added the /dev/crash memory driver Makefile and source file to
the crash package for live system analysis when the target
system's kernel was configured with CONFIG_STRICT_DEVMEM, or was
not configured with CONFIG_PROC_KCORE, or whose /proc/kcore is
simply not functional. The driver can be built and installed by
entering the memory_driver subdirectory and entering "make", and
then "insmod crash.ko". If the module is successfully installed,
it will be used by default for live crash sessions.

- Fix for the "extend -u" command option. Without the patch, after
the successful unloading of a crash extension module, there may be
an invalid error message that indicates "extend: <module>.so and
<module>.so are different".

- Implement support for Xen version 4 hypervisor dumpfiles:
1. Accept the "__per_cpu_shift" symbol. Without the patch, crash
initialization fails on X86, X86_64 and IA64 dumpfiles.
2. Make the x86_64 XEN_VIRT_START value a variable dependent upon
the Xen version. Without the patch, crash initialization fails
on x86_64 dumpfiles.
3. In Xen version 4, "init_tss" is a per-cpu symbol. Without this
patch, crash fails during initialization with the error message
"crash: cannot resolve init_tss" on X86 and X86_64 dumpfiles.
4. Each domain can have a different number of max VCPUs in Xen
version 4. Prepare for this by converting the static array into
a dynamic one.
5. If the size of the vcpu array in struct domain is known, use it
to size the dynamically allocated vcpu array in crash. This
enables crash to initialize domains with a different number of
VCPUs than specified by the XEN_HYPER_MAX_VIRT_CPUS macro.
6. The "vcpu" field changed from a fixed array to a pointer to an
array. The size of the array is stored in the (newly introduced)
"max_vcpus" field. Modify xen_hyper_store_domain_context() to
account for this change.
7. The command line options (such as opt_sched) are discarded after
boot in Xen version 4, so they are no longer available. Use the
"ops" variable (if it exists) to determine the active scheduler.
Without this patch, crash fails during initialization with the
error message "crash: schedule data not found".

- Created a new extension module API:

int load_module_symbols_helper(char *module);

It takes a kernel module name as an argument, and performs the same
procedure as the command "mod -s <module>".
(nakayama.ts@ncos.nec.co.jp, anderson@redhat.com)

- When loading debuginfo data for kernel module object files with the
"mod" command or with the new load_module_symbols_helper() extension
module API, search a non-standard directory path by specifying the
directory tree in the CRASH_MODULE_PATH shell environment variable.
(nakayama.ts@ncos.nec.co.jp, anderson@redhat.com)

- Created a new extension module API:

int get_kernel_config(char *conf_name, char **str);

The kernel must be configured with CONFIG_IKCONFIG. It takes a
kernel configuration item string, which may be of the format
"CONFIG_XXX" or just "XXX", and a pointer to a char *. The function

IKCONFIG_Y: configuration item is built into the kernel
IKCONFIG_M: configuration item is part of a kernel module
IKCONFIG_STR: configuration item consists of a string
IKCONFIG_N: the kernel is not configured with CONFIG_IKCONFIG or
the configuration item is not configured.

If "Y", "M" or "STR", the configuration item's string representation
will be pointed to by the passed-in "str" pointer.
(nakayama.ts@ncos.nec.co.jp, anderson@redhat.com)

- Update of the "extensions/trace.c" extension module. Initially
designed to support 2.6.32 (RHEL6), it has been updated to support
kernels up to 2.6.38-rc1.

- Fix for the internal parse_line() function to properly handle
multiple string arguments. Without the patch, the second, fourth,
etc., string argument would get broken up into individual tokens.

- Updates to support ARM page table changes and PTE differences that
were introduced in 2.6.38 kernels. Deleted two irrelevant ARM-only
source code comments.

- Removed two unused "struct syment" local variable declarations in
the gdb_add_symbol_file() function in gdb-7.0/gdb/symtab.c.

- Replaced the usage of the VOID_PTR() macro with the ULONG() macro for
structure member accesses in vm_area_dump(), vm_area_page_dump() and

- Implemented support for makedumpfile's "vmcore.flat" dumpfile format.
It is no longer necessary to revert the flat dumpfile back into an
ELF vmcore or compressed kdump vmcore with "makedumpfile -R", or with
the "makedumpfile-R.pl" script. Without the patch, attempting to use
a flat dumpfile fails with the message "crash: vmcore.flat: not a
supported file format".

- Moved the GDB_CONF_FLAGS logic from the Makefile into configure.c.

- Use memset() in the shift_string_right() utility function, and use
shift_string_right() and memset() in the mkstring() utility function.

- Added a new "search -p" option to search physical memory. Until now
only kernel virtual memory and user virtual memory of the current
context could be searched.

- Optimization of the "search -k" function resulting in a significant
time reduction when cycling through vmalloc memory space.

- Added a new "search -K" option, which searches a subset of kernel
virtual memory, restricting the search to kernel unity-mapped virtual
memory, and on the x86_64 and ia64 machines, their discretely mapped
kernel-text/static-data regions.

- Added a new "search -V" option, which searches a subset of kernel
virtual memory, restricting the search to kernel virtual memory
that was allocated by vmalloc(), kernel module memory, and the
virtual mem_map region if it exists on x86_64, ia64, ppc64 and
s390x machines.

- Reworked the functionality of the "search" command to break up kernel
virtual memory into machine-dependent address regions so that the
cycling through disparate virtual address regions can be done in a
more efficient manner.

- Fix for "search -k" on x86_64. Early 2.6 kernels did not have their
module virtual address space included in the kernel's "vmlist" array;
without the patch, module memory is not searched.

- Fix for "search -k" on x86_64. Without the patch, the kernel's
mapped kernel text/static-data region is not searched as a separate

- Fix for "search -k" on architectures that may have a virtual memmap,
such as x86_64, ia64, ppc64 and s390x. Without the patch, virtual
memmap array memory is not searched.

- Fix for "search -k" on s390x. Without the patch, the command may
end prematurely with the error message "search: read error: kernel
virtual address: 0 type: entry".

- Fix for "search" command to prevent unnecessary read error messages
for memory pages that are not contained in a xendump dumpfile.
Without the patch, the output may be interspersed with messages that
indicate "search: cannot find mfn in page index".

- Fix for a compile failure of the embedded gdb-7.0/bfd/verilog.c file
due to a smarter -Werror flag used by gcc-4.6.

Download from: http://people.redhat.com/anderson

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