[Crash-utility] [ANNOUNCE] crash version 6.1.2 is available
Dave Anderson
anderson at redhat.com
Wed Jan 9 15:50:50 UTC 2013
Download from: http://people.redhat.com/anderson
Changelog:
- Enhancement of the "task" command to display both the task_struct
and the thread_info structures of a task. The -R option accepts
members of either/both structure types.
(anderson at redhat.com)
- Fix for the X86_64 "search" and "rd" commands due to this commit:
http://git.kernel.org/linus/027ef6c87853b0a9df53175063028edb4950d476
Upon any attempt to read a page within the RAM region reserved for
AMD GART on a live system, the Linux 3.7rc1 commit above causes
causes /dev/mem, /proc/kcore and the /dev/crash drivers to spin
forever, leading to a kernel soft lockup. The RAM pages reserved for
GART consist of 2MB large pages whose _PAGE_PRESENT bits are turned
off. Prior to the above commit, a read() attempt on GART RAM would
cause an unresolvable page fault, and would harmlessly return an
EFAULT. The commit above has changed pmd_large() function such that
it now returns TRUE if only _PAGE_PSE bit is set in the PTE, whereas
before it required both _PAGE_PSE and _PAGE_PRESENT. So instead of
just failing the read() system call with an EFAULT, the page fault
handling code now considers it a spurious TLB fault, and the
instruction is retried indefinitely. The crash utility patch stores
the GART physical memory range, and disallows any attempts to read
from it.
(anderson at redhat.com)
- If an EPPIC_GIT_URL environment variable is defined, then the URL
that it points to is used as an alternative to the code.google.com
git source repository for the eppic.so extension module. However,
the alternative site is only accessed if code.google.com can first
be pinged; this patch removes that restriction.
(per.fransson.ml at gmail.com)
- Fix for the "files" command PATH display on kernels configured with
CONFIG_DEVTMPFS, when the vfsmount pointer in an file structure's
"f_path" member does not point to the root vfsmount required for
reconstructing the full file pathname. Without the patch, open files
in /dev directory may be truncated and not show the "/dev" filename
component.
(anderson at redhat.com)
- Enhancement to the "kmem -v" option on 2.6.28 and later kernels that
utilize the "vmap_area_list" list of mapped kernel virtual memory
regions, replacing the usage of the to-be-obsoleted "vmlist" list.
In those kernels, the output of the command will also show each
vmap_area structure address, in addition to its vm_struct address,
memory range, and size.
(anderson at redhat.com)
- Update to the exported do_rbtree() and do_rdtree() functions such
that they will return the number of items found in the targeted tree,
similar in nature to the do_list() function. The two functions have
also been fixed such that the VERBOSE flag is actually recognized,
so that external callers are able to gather the entries in a tree
without having them displayed. The calls to either function may be
enclosed with hq_open() and hq_close() so the that tree entries may
be subsequently gathered by retrieve_list() into a supplied buffer,
as well as to recognize a corrupted list with duplicate entries.
(anderson at redhat.com)
- Fix for the "extend -u" option to prevent the usage of a member of
a free()'d extension_table structure. No command failure occurs,
but rather an inadvertent coding error.
(Jan.Karlsson at sonymobile.com)
- Fix to allow error() to be called during an open_tmpfile() sequence
prior to close_tmpfile() being called. There are no crash functions
that call error() during an open_tmpfile() sequence, but there's no
reason why it cannot be done. Without the patch, the error message
gets displayed on stdout (as expected), but the error message will
also overwrite/corrupt the tmpfile() data while it is being parsed.
(anderson at redhat.com)
- Fix to properly determine whether X86_64 kernels were configured
with CONFIG_FRAME_POINTER, due to this ftrace-related commit:
http://git.kernel.org/linus/d57c5d51a30152f3175d2344cb6395f08bf8ee0c
Without the patch, the crash utility fails to determine whether the
kernel was built with CONFIG_FRAME_POINTER, and therefore the "bt"
command cannot take advantage of it for more reliable backtraces.
(anderson at redhat.com)
- Fix to properly determine whether 2.6.31 and earlier X86_64 kernels
were configured with CONFIG_FRAME_POINTER. Without the patch, the
crash utility may fail to determine whether the kernel was built with
CONFIG_FRAME_POINTER. In those kernel versions -- which may be
dependent upon the compiler version used -- one of the sample
functions tested may have their "push %rbp, mov %rsp,%rbp" function
preamble separated by other instruction(s), resulting in a false
negative that precludes the "bt" command from taking advantage of
framepointers.
(anderson at redhat.com)
- Fix for the file and line-number string that is displayed by the
"sym <kernel-text>" option. Without the patch, the "/usr/src/"
part of the string is stripped, and the filename string itself
could have two corrupted characters in the pathname, for example,
showing "k3.nel-3.6.fc17" instead of "kernel-3.6.fc17". This is
dependent upon the compiler version, or perhaps the string library
that is linked into the crash binary, because it only has been seen
on crash binaries built with gcc-4.7. The fix now displays the full
pathname, no longer dropping the "/usr/src" from beginning.
(anderson at redhat.com)
- Restricted the X86_64 "line_number_hook" to kernels earlier than
2.6.24, i.e., kernels prior to the x86/x86_64 merge. Without the
patch, the manufactured filename information for assembly-language
files was incorrect for 2.6.24 and later kernels. Also, the kernel
debuginfo data now has file/line-number data for assembly-language
files as well, obviating the need for the hook.
(anderson at redhat.com)
- Fix for the extensions/trace.c extension module to prevent a double
free exception that would occur if a calloc() call fails during
module initialization.
(per.fransson.ml at gmail com)
- Fix for the "p -u" option if a 32-bit kernel symbol is incorrectly
passed as an argument. Without the patch, the command fails, but
the next command requiring the services of the embedded gdb module
will generate an error message of the sort "*** glibc detected ***
crash: free(): invalid pointer: <address> ***", or "*** glibc
detected *** crash: munmap_chunk(): invalid pointer: <address> ***",
followed by a backtrace, and an abort of the crash session.
(anderson at redhat.com)
- Fix for the embedded gdb module to correctly handle kernel modules
whose ELF header contains "__ksymtab" and "__ksymtab_gpl" sections
with non-zero (nonsensical) "Address" values, such as those shown
in this example snippet:
$ readelf -a edac_core.so
...
Section Headers:
[Nr] Name Type Address Offset
Size EntSize Flags Link Info Align
...
[ 8] __ksymtab PROGBITS 0000000000000060 0000ad90
0000000000000010 0000000000000000 A 0 0 16
...
[10] __ksymtab_gpl PROGBITS 0000000000000070 0000add0
00000000000001a0 0000000000000000 A 0 0 16
...
Without the patch, if one of the odd sections above is encountered,
the "Offset" values of the remaining sections are not processed; and
if the module's .data section is ignored, gdb incorrectly calculates
the address of all symbols in the module's .data section, leading to
incorrect output if, for example, data is printed with the gdb "p"
command. This invalid ELF section format was introduced in Linux 3.0
by the kernel's "scripts/module-common.lds" file.
(jan.kratochvil at redhat.com)
- Fix for the "runq -g" option if the kernel contains more than 200
task groups. Without the patch, the command generates a segmentation
violation.
(anderson at redhat.com)
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