"kimage_voffset" value in the ELF header. Without the patch, it is
necessary to use the "--machdep kvimage_offset=<value>" command line
option, or the session fails with the message "crash: vmlinux and
vmcore do not match!".
(anderson@redhat.com)
where the task_struct contains a "randomized_struct_fields_start" to
"randomized_struct_fields_end" section. Without the patch, a member
argument that is inside the randomized section is not found.
(anderson@redhat.com)
Without the patch, a message indicating "crash: builtin stackframe.sp
offset incorrect!" is issued during session initialization, and the
"bt" command fails with the error message "bt: invalid structure
member offset: task_struct_thread_context_sp".
(anderson@redhat.com)
x86_64 "bt" command. Kernels configured with CONFIG_ORC_UNWINDER
contain .orc_unwind and .orc_unwind_ip sections that can be queried
to determine the stack frame size of any text address within a kernel
function. For kernels not configured with CONFIG_FRAME_POINTER,
the crash utility does frame size calculation by disassembling a
function from its beginning to the specified text address, counting
the push, pop, and add/sub rsp instructions, accounting for retq
instructions that occur in the middle of a function. With this patch,
access to the new ORC sections has been plugged into the existing
frame size calculator, resulting in a more efficient and accurate
manner of determining frame sizes, and as a result, more accurate
backtraces.
(anderson@redhat.com)
frame at the top of the stack in Linux 4.7 and later kernels.
Without the patch, the contents of the user mode exception frame are
invalid due to the miscalculation of the starting address of the
pt_regs structure on the kernel stack.
(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)
in use. Without the patch, the message may not get displayed
if the --kaslr option is used, or if the dumpfile is a vmcore
generated by the current snap.so extension module, which now
exports the relocation value in the header.
(anderson@redhat.com)
the max real address to 53 bits. Without this patch, the warning
message "WARNING: cannot access vmalloc'd module memory" appears
during initialization, and any command that attempts to read a
vmalloc'd kernel virtual address will fail and display "read error"
messages.
(hbathini@linux.vnet.ibm.com)
With kernel commit ea417aa8a38bc7db ("s390/debug: make debug event
time stamps relative to the boot TOD clock") for s390dbf time is
stored relative to the kernel boot time. In order to still show
absolute time since 1970 we have to detect those kernels and re-add
the boot time before printing the records. We can use the
tod_to_timeval() symbol to check for those kernels because the
patch has removed the symbol. With kernel commit 6e2ef5e4f6cc5734
("s390/time: add support for the TOD clock epoch extension")
the symbol name for storing the boot time has changed from
"sched_clock_base_cc" to "tod_clock_base". This commit is currently
on the s390 features branch and will be integrated in Linux 4.14.
(holzheu@linux.vnet.ibm.com)
"mm: consider zone which is not fully populated to have holes".
Without the patch, SPARSEMEM page struct addresses are incorrectly
calculated because a new section state, and an associated flag bit,
has been added to the low bits of the mem_section.section_mem_map
address; the extra bit is erroneously passed back as part of the
section_mem_map and resultant page struct address, leading to
errors in commands such as "kmem -p", "kmem -s", "kmem -n", and any
other command that translates a physical address to its page struct
address.
(anderson@redhat.com)
the user id of the builder, and the build machine hostname, and is
viewable by the "crash --buildinfo" command line option or by the
"help -B" option during runtime. This patch replaces that string
data with "reproducible build" if the SOURCE_DATE_EPOCH environment
variable contains a value string when the crash binary is compiled.
(bwiedemann@suse.de)
"x86/boot/64: Rename init_level4_pgt and early_level4_pgt". Without
the patch, the crash session fails during initialization with the
error message "crash: cannot resolve "init_level4_pgt".
(anderson@redhat.com)
a user whose username cannot be determined from the user ID number,
the build fails immediately with a segmentation fault.
(sargun@sargun.me, anderson@redhat.com)
sets of virtual memory offsets have been #define'd and helper macros
and placeholder functions for the p4d page tables have been added.
The only functional changes with this patchset are dynamically-set
PGDIR_SHIFT and PHYSICAL_MASK_SHIFT values that are based upon the
kernel configuration.
(anderson@redhat.com)
encounters duplicate entries in a radix_tree_node[slots] array.
Without the patch, if a duplicate slot entry is found, the command
fails with the message "tree: duplicate tree entry: radix_tree_node:
<node address> slots[<index>]: <entry>\n". (The error can
be prevented if the command is preceded by "set hash off".) However,
certain radix trees contain duplicate entries by design, such as the
"pgmap_radix" radix tree, in which a radix_tree_node may contain
multiple instances of the same page_map structure. With the patch,
checks will only be made for duplicate radix_tree_node structures.
(anderson@redhat.com)
options. When a fatal error is encountered while gathering basic
CONFIG_SLUB statistics, it is possible that the slab cache name
is not displayed in the error message, and the line containing
the slab cache name, address, etc., is not displayed at all. With
this patch, an extra error message indicating "kmem: <cache-name>:
cannot gather relevant slab data" will be displayed under the
fatal error message; and under that, the CACHE address, cache NAME,
OBJSIZE, and SSIZE columns will be displayed, but with "?" under
the ALLOCATED, TOTAL, and SLABS columns.
(anderson@redhat.com)
of a "symbol+offset" argument where the duplicates are not contiguous
in the symbol list. Without the patch, the first of multiple symbol
instances is used in the address evaluation. With the patch, the
command will fail with the error message "dis: <symbol+offset>:
duplicate text symbols found:", followed by a list of the duplicate
symbols, and their file and line numbers if available.
(anderson@redhat.com)
support for dom0 with Linux kernel 3.19 and newer) from Daniel Kiper
implemented support for Xen dom0 vmcores after Linux 3.19 kernel
commit 054954eb051f35e74b75a566a96fe756015352c8 (xen: switch to
linear virtual mapped sparse p2m list). This patch can be deemed
subsequent to Daniel's patch, and implements support Xen PV domU
dumpfiles for Linux 3.19 and later kernels.
(honglei.wang@oracle com)
page tables where user space memory is mapped above 8 Petabytes.
Without the patch, "rd -u" fails and indicates "invalid user virtual
address", and "vtop -u" indicates that the address is "(not mapped)".
(zaslonko@linux.vnet.ibm.com)
been installed on the host build machine. Without the patch, the
build fails with the error message "mips-linux-nat.c:157:1: error:
conflicting types for 'ps_get_thread_area'".
(dengke.du@windriver.com)
backported commit 401721ecd1dcb0a428aa5d6832ee05ffbdbffbbe, titled
"kexec: export the value of phys_base instead of symbol address".
Without the patch, if the x86_64 "phys_base" value in the VMCOREINFO
note is a negative negative decimal number, the crash session fails
during session intialization with a "page excluded" or "seek error"
when reading "page_offset_base".
(anderson@redhat.com)
contain commit 475339684ef19e46f4702e2d185a869a5c454688, titled
"x86/e820: Prepare e280 code for switch to dynamic storage", in
which the "e820" symbol was changed from a static e820map structure
to a pointer to an e820map structure. Without the patch, the
command either displays just the header, or the header with several
nonsensical entries.
(anderson@redhat.com)
compiled with CONFIG_RANDOMIZE_BASE because the embedded gdb module
still operates under the assumption that the (non-relocated) text
locations in the vmlinux file are correct. The error message that
is issued is somewhat confusing, indicating "No function contains
specified address". This patch simply clarifies the error message
to indicate "crash: the gdb "disassemble" command is prohibited
because the kernel text was relocated by KASLR; use the crash "dis"
command instead."
(anderson@redhat.com)
offset value in the dumpfile header for kernels that are compiled
with CONFIG_RANDOMIZE_BASE. Without the patch, it is necessary to
use the "--kaslr=<offset>" command line option, or the session
fails with the message "WARNING: cannot read linux_banner string",
followed by "crash: vmlinux and vmcore do not match!".
(anderson@redhat.com)
the ppc64 architecture. Without the patch, the trace.so extension
module fails to load, indicating "extend: invalid text address:
ring_buffer_read". On the ppc64 architecture, the text symbol
is ".ring_buffer_read".
(anderson@redhat.com)
Linux 4.7 kernel commit 9b94a8fba501f38368aef6ac1b30e7335252a220,
which changed the ring_buffer_per_cpu.nr_pages member from an int
to a long. Without the patch, the trace.so extension module fails
to load on big-endian machines, indicating "extend: Num of pages
is less than 0".
(feij.fnst@cn.fujitsu.com)
CONFIG_RANDOMIZE_BASE. Without the patch, the command fails with
the message "set: gdb cannot find text block for address: <symbol>".
This also affects extension modules that call gdb_set_crash_scope()
when running with KASLR kernels.
(anderson@redhat.com)
of a "symbol+offset" argument where the duplicates are contiguous
in the symbol list. In addition, reject "symbol+offset" arguments
if the resultant address goes beyond the end of the function.
(anderson@redhat.com)
not passed in the VMCOREINFO data of ELF vmcores. Without the patch,
it is possible that the base address of the vmalloc region is unknown
and initialized to an incorrect default address during the very early
stages of initialization, which causes the parsing of the PT_LOAD
segments for the START_KERNEL_map region to fail.
(anderson@redhat.com)
encountered that contains an invalid NULL pointer. Without the
patch, the "list -[hH]" options would complete/continue as if the
NULL were a legitimate end-of-list indicator, and no error would be
reported.
(rabin.vincent@axis.com)
on the host build machine. Without the patch, the build fails with
the error message "amd64-linux-nat.c:496:1: error: conflicting types
for 'ps_get_thread_area'".
(anderson@redhat.com)
to signficantly reduce the amount of time to complete the buddy
allocator free-list scan for the target address. On very large
memory systems, the patch may reduce the time spent by several orders
of magnitude.
(anderson@redhat.com)
in Linux 4.6 and later kernels if an ELF format dumpfile does not
contain its value in a VMCOREINFO note, or when running against
live systems using /dev/mem, /proc/kcore, or an older version of
/dev/crash.
(liyueyi@live.com)
in x86_64 kernels that contain, or have backports of, kernel commit
7c1da8d0d046174a4188b5729d7579abf3d29427, titled "crypto: sha - SHA1
transform x86_64 AVX2", which introduced an "_end" text symbol.
Without the patch, if a base kernel symbol address that is larger
than the "_end" text symbol is passed to "kmem <address>", its
symbol/filename information will not be displayed. Also, when the
"search" command scans the __START_KERNEL_map region that contains
kernel text and static data, the search will be truncated to stop at
the "_end" text symbol address.
(anderson@redhat.com)
of one or more symbol values of a kernel module. Without the patch,
when loading a kernel module, a message may indicate "mod: <module>:
last symbol: <symbol> is not _MODULE_END_<module>?" may be displayed,
and one or more symbols may be reassigned an incorrect symbol value.
If none of the erroneous symbol value reassignments are beyond the
end of the module's address space, then there will be no message.
(anderson@redhat.com)
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)
