command to generate a segmentation violation. The bug is
dependant upon the compiler version used to build the crash
utility, where a buffer overrun is not seen with more recent
versions of gcc, which hide the bug due to a different stack
layout of a function's local varibles.
(anderson@redhat.com)
memory driver do not exist, try to use "/proc/kcore". Without
the patch, the session fails immediately with the error message
"crash: /dev/mem: No such file or directory".
(anderson@redhat.com)
when building with "make warn". The warnings are all false alarm
messages of type [-Wformat-overflow=], [-Wformat-truncation=] and
[-Wstringop-truncation]; the affected files are extensions.c, task.c,
kernel.c, memory.c, remote.c, symbols.c, filesys.c and xen_hyper.c.
(anderson@redhat.com)
selecting the unusable "vmlinux.o" file found in private build
directories. Without the patch, the non-executable vmlinux.o file
may be selected, and the resulting fatal error message indicates a
somewhat misleading "crash: cannot resolve _stext".
(bhsharma@redhat.com, anderson@redhat.com)
commit e8cfbc245e24887e3c30235f71e9e9405e0cfc39, titled "pid: remove
pidhash". The kernel's traditional usage of a pid_hash[] array to
store PIDs has been replaced by an IDR radix tree, requiring a new
crash plug-in function to gather the system's task set. Without the
patch, the crash session fails during initialization with the error
message "crash: cannot resolve init_task_union".
(anderson@redhat.com)
session on a host system that does not have a "/usr/src" directory.
Without the patch, the session fails with the message "*** Error in
'crash': free(): invalid pointer: <address> ***".
(Lei Chen)
when building with "make warn". The warning types are "[-Wnonnull]"
in filesys.c, and "[-Wformat-overflow=]" in kernel.c and cmdline.c.
(anderson@redhat.com)
in Linux 4.6 and later kernels due to upstream changes in the radix
tree facility. Without the patch, the commands will fail with the
message "radix trees do not exist or have changed their format".
(hirofumi@mail.parknet.co.jp)
are specified by the QEMU mem-path argument of a memory-backend-file
object. This allows the running of a live crash session against a
QEMU guest from the host machine. In this example, the /tmp/MEM file
on a QEMU host represents the guest's physical memory:
$ qemu-kvm ...other-options... \
-object memory-backend-file,id=MEM,size=128m,mem-path=/tmp/MEM,share=on \
-numa node,memdev=MEM -m 128
and a live session run can be run against the guest kernel like so:
$ crash <path-to-guest-vmlinux> live:/tmp/MEM@0
By prepending the ramdump image name with "live:", the crash session will
act as if it were running a normal live session.
(oleg@redhat.com)
of major(), minor() and makedev(). These functions are defined
in the sys/sysmacros.h header, not sys/types.h. Linux C libraries
are updating to drop the implicit include, so we need to include
it explicitly.
(vapier@gentoo.org)
option is context-sensitive, similar to the the regular "files"
command when used without an argument, but replaces the FILE and
DENTRY columns with I_MAPPING and NRPAGES columns that reflect
each open file's inode.i_mapping address_space structure address,
and the address_space.nrpages count within it; this shows how
many of each open file's pages are currently in the system's
page cache. The "files -p <inode>" option takes the address
of an inode, and dumps all of its pages that are currently in the
system's page cache, borrowing the "kmem -p" page structure output.
(yangoliver@gmail.com)
they are used in an input file. If more than one of any of those
four commands are used in an input file, the output of the second
and subsequent command instances will not display their respective
command headers.
(anderson@redhat.com)
Similar to all other supported dumpfile types, it is invoked as:
$ crash vmlinux <vmname>.vmss
A "<vmname>.vmss" file created by the VMware vSphere ESX hypervisor
contains a header and the full memory image. A "<vmname>.vmss" file
created by the VMware Workstation facility only contains the header,
and must be accompanied by a companion "<vmname>.vmem" memory image
that is located in the same directory as the "<vmname>.vmss" file.
(hfu@vmware.com)
built on an X86_64 host with "make target=X86" or "make target=ARM"
is used on a live X86_64 system without specifying a vmlinux
namelist. Without the patch, the session fails with the message
"crash: cannot find booted kernel -- please enter namelist argument".
The error message will be "crash: compiled for the X86 architecture"
or "crash: compiled for the ARM architecture".
(anderson@redhat.com)
are searched for the currently-running kernel on live systems. This
will automatically locate the vmlinux namelist for kernels that were
locally installed with "make modules_install install".
(lrintel@redhat.com)
be compressed and named "crash.ko.xz". Without the patch, the driver
is not recognized and loaded, and as a result the /dev/mem driver
and/or /proc/kcore will be tried as the live memory source.
(anderson@redhat.com)
for Linux 3.13 and later kernels if the option is attempted, and in
the "help mount" output, similar to the deprecated "mount -d" option.
(anderson@redhat.com)
containing commit eee5cc2702929fd41cce28058dc6d6717f723f87, which
removed the super_block.s_files list_head member and the open files
list that it contained. Without the patch, the command option fails
with the error message "mount: invalid structure member offset:
super_block_s_files"
(anderson@redhat.com)
