has appended a NULL entry as the final member of the pageflag_names[]
array. Without the patch, a message that indicates "crash: failed to
read pageflag_names entry" is displayed during session initialization
in Linux 4.6 kernels.
(andrej.skvortzov@gmail.com)
sections used for live migration of KVM guests, which are seen in
the "kvmdump" format generated if "virsh dump" is used without the
"--memory-only" option.
(pagupta@redhat.com)
--memory-only" facility if the guest kernel was not configured with
CONFIG_KEXEC, or CONFIG_KEXEC_CORE in Linux 4.3 and later kernels.
Without the patch, the crash session fails during initialization with
the message "crash: cannot resolve kexec_crash_image".
(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)
version supports running against a live kernel. Compressed kdump
support is also here, but the crash dump support for the kernel,
kexec-tools, and makedumpfile is still pending. Initial work was
done by Karl Volz with help from Bob Picco.
(dave.kleikamp@oracle.com)
pte_present() function, which checks for either _PAGE_PRESENT or
_PAGE_PROTNONE to be set. Without the patch, user pages whose PTE
does not have _PAGE_PRESENT bit set are misconstrued as SWAP pages
with an "(unknown swap location") along with a bogus OFFSET value.
(anderson@redhat.com)
Without the patch, if a freelist pointer is corrupt, the address of
the slab page being referenced may not be displayed by the error
message, showing something like: "kmem: kmalloc-32: slab: 0 invalid
freepointer: 6e652f323a302d74".
(hirofumi@mail.parknet.co.jp)
Without the patch, the count displayed in the ALLOCATED column may
be too large, and the "kmem -S" display of allocated/free status of
individual objects may be incorrect.
(hirofumi@mail.parknet.co.jp)
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)
version of the gdb-7.6.patch in a pre-existing build directory.
Without the patch, it is possible that a previously-applied patch
could be applied a second time without the fuzz restriction.
(anderson@redhat.com)
option searches for data structures of a specified size or within a
range of specified sizes. The -m option searches for data structures
that contain a member of a given type. If a structure contains
another structure, the members of the embedded structure will also
be subject to the search. The type string may be a substring of the
data type name. The output displays the size and name of the data
structure.
(Alexandr_Terekhov@epam.com, anderson@redhat.com)
previous patch:
memory.c: In function ‘count_cpu_partial’:
memory.c:17958: warning: comparison is always false due to limited
range of data type
memory.c: In function ‘count_partial’:
memory.c:18729: warning: comparison is always false due to limited
range of data type
(anderson@redhat.com)
kmem_cache shown by "kmem -s" in kernels configured with CONFIG_SLUB.
Without the patch, the values under the ALLOCATED column may be too
large because cached per-cpu objects are counted as allocated.
(vinayakm.list@gmail.com)
address is the highest text symbol value in a kernel module. Without
the patch, the disassembly may continue past the end of the function,
or may show nothing at all. The patch utilizes in-kernel kallsyms
symbol size information instead of disassembling until reaching the
address of the next symbol in the module.
(anderson@redhat.com)
this kernel commit for Linux 4.5 and later kernels:
commit 8244062ef1e54502ef55f54cced659913f244c3e
modules: fix longstanding /proc/kallsyms vs module insertion race.
Without the patch, the crash session fails during initialization
with the error message: "crash: invalid structure member offset:
module_num_symtab".
(anderson@redhat.com)
cpu_possible_mask, cpu_present_mask and cpu_active_mask symbols in
the kernel commit for Linux 4.5 and later kernels for when the
crash session is brought up with "crash -d<debug-level>". Without
the patch, the cpus found in each mask are displayed like this
example:
cpu_possible_(null): cpus: 0 1 2 3 4 5 6 7
cpu_present_(null): cpus: 0 1
cpu_online_(null): cpus: 0 1
cpu_active_(null): cpus: 0 1
The "(null)" string segments above should read "mask".
(anderson@redhat.com)
are generated by the following files, when building X86_64 in a
Fedora Rawhide environment with gcc-6.0.0:
gdb-7.6/gdb/ada-lang.c
gdb-7.6/gdb/linux-record.c
gdb-7.6/gdb/inflow.c
gdb-7.6/gdb/printcmd.c
gdb-7.6/gdb/c-typeprint.c
Without the patch, warnings in the gdb-7.6/gdb directory are not
treated as errors, and are non-fatal to the build.
(anderson@redhat.com)
which were introduced in Linux 4.5 by this commit:
commit 132cd887b5c54758d04bf25c52fa48f45e843a30
arm64: Modify stack trace and dump for use with irq_stack
Without the patch, if an active task was operating on its per-cpu
IRQ stack on dumpfiles generated by kdump, its backtrace would start
at the exception frame that was laid down on the process stack.
This patch also adds support for "bt -E" to search IRQ stacks for
exception frames, and the "mach" command displays the addresses
of each per-cpu IRQ stack.
(anderson@redhat.com)
is generated by "gdb-7.6/opcodes/mips-dis.c" when building with
"make target=MIPS" on an x86_64 host with gcc-6.0.0. Without the
patch, the warning is treated as an error and the build is aborted.
(anderson@redhat.com)
warnings that are generated by "gdb-7.6/bfd/elf64-ppc.c" and
"gdb-7.6/opcodes/ppc-opc.c" when building with "make target=PPC64"
on an x86_64 host with gcc-6.0.0. Without the patch, the warnings
are treated as errors and the build is aborted.
(anderson@redhat.com)
generated by "gdb-7.6/opcodes/arm-dis.c" when building crash with
"make target=ARM64" on an x86_64 host with gcc-6.0.0. Without the
patch, the warning is treated as an error and the build is aborted.
(anderson@redhat.com)
are generated by the following files, when building X86_64 in a
Fedora Rawhide environment with gcc-6.0.0:
gdb-7.6/bfd/coff-i386.c
gdb-7.6/bfd/coff-x86_64.c
kernel.c
x86_64.c
lkcd_common.c
Without the patch, the warnings in the bfd library files are treated
as errors, and abort the build. The three instances in the top-level
crash source code directory are non-fatal. There are several other
gdb-specific instances that are non-fatal and are not addressed.
(anderson@redhat.com)
cpu_online_mask, cpu_present_mask and cpu_active_mask symbols in
this kernel commit for Linux 4.5 and later kernels:
commit 5aec01b834fd6f8ca49d1aeede665b950d0c148e
kernel/cpu.c: eliminate cpu_*_mask
Without the patch, behavior is architecture-specific, dependent upon
whether the cpu mask values are used to calculate the number of cpus.
For example, ARM64 crash sessions fail during session initialization
with the error message "crash: zero-size memory allocation! (called
from <address>)", whereas X86_64 sessions come up normally, but
cpu mask values of zero are stored internally.
(anderson@redhat.com)
since this Linux 3.19 commit:
commit 054954eb051f35e74b75a566a96fe756015352c8
xen: switch to linear virtual mapped sparse p2m list
This patch resurrects support for dom0 dumpfiles only. Without the
patch, the crash session fails during session initialization with the
message "crash: cannot resolve p2m_top".
(daniel.kiper@oracle.com)
this kernel commit for Linux 4.5 and later kernels:
commit 7523e4dc5057e157212b4741abd6256e03404cf1
module: use a structure to encapsulate layout.
Without the patch, the crash session fails during initialization
with the error message: "crash: invalid structure member offset:
module_init_text_size".
(sebott@linux.vnet.ibm.com)
commit ccbf62d8a284cf181ac28c8e8407dd077d90dd4b, which changed the
task_struct.start_time member from a struct timespec to a u64.
Without the patch, the "RUN TIME" value is nonsensical.
(anderson@redhat.com)
registers from the NT_PRSTATUS notes of 32-bit tasks running in
user-mode on ARM64. Without the patch, the "bt" command utilizes
ptregs->sp and ptregs->regs[29] for 32-bit tasks instead of the
architecturally-mapped ptregs->regs[13] and ptregs->regs[11], which
yields unpredictable/invalid results, and possibly a segmentation
violation.
(drjones@redhat.com)
dumpfiles because some Fujitsu troubleshooting software assumes the
behavior. Also, fix the "set -v" option to show the "zero_excluded"
internal variable as "on" if it has been set when analyzing SADUMP
dumpfiles.
(d.hatayama@jp.fujitsu.com)
region between 0xffffffffff600000 and 0xffffffffffe00000. Without
the patch, the reading of addresses in that region returns invalid
data; in addition, the "vtop" command for an address in that region
shows an invalid physical address under the "PHYSICAL" column.
(nakajima.akira@nttcom.co.jp, anderson@redhat.com)
pre-gathering of p2m frames during session initialization, which
is unnecessary since ELF files contain the mapping information in
their ".xen_p2m" section. Without the patch, it is possible that the
crash session may be unnecessarily aborted if the p2m frame-gathering
fails, for example, if the CR3 value in the header is invalid.
(ptesarik@suse.com)
on/off with the "set" command. When set to "on", gdb's printing of
arrays will be set to "pretty", so that the display of each array
element will consume one line.
(anderson@redhat.com)
during session initialization. This includes the system's cpu maps,
xtime, and utsname data. These require at least "-d1" as a command
line option value, and are primarily useful as an aide for debugging
suspect dumpfiles that fail during session initialization.
(anderson@redhat.com)
conjunction with "-s", and requires that the "start" address is the
address of a list_head, or other similar list linkage structure whose
first member points to the next linkage structure. The "-l <offset>"
argument is the offset of the embedded list linkage structure in the
specified "-s" data structure; it can be either a number of bytes or
expressed in "struct.member" format.
(anderson@redhat.com)
and contain percpu array_cache structures that were allocated with
vmalloc(). Without the patch, during session initialization there
will be error messages of the form: "crash: kmem_cache: <vaddr>:
invalid array_cache pointer: <vaddr>", and during runtime, the
"kmem -[sS]" commands will show kmem_cache lines that marked as
"[INVALID/CORRUPTED]".
(anderson@redhat.com)
the kernel has dynamically downsized from the size indicated by the
debuginfo data. At this time, only "kmem_cache" and "task_struct"
structures that have been downsized are registered, but others may be
added in the future. If a downsized data structure is passed to gdb
for display, gdb will request a read of the "full" data structure,
which may flow into a memory region that was either filtered by
makedumpfile(8), or perhaps into non-existent memory, thereby killing
the generating command immediately due to a partial read. With this
patch, commands such as "struct" and "task" that reference downsized
data structures will have their reads flagged to return successfully
if partial read error occurs.
(anderson@redhat.com)
