and earlier x86_64 kernels configured with CONFIG_RANDOMIZE_BASE.
A segmentation violation may occur during session initialization,
just after the patching of the gdb minimal_symbol values message,
depending upon the value of KERNEL_IMAGE_SIZE, which was variable
in the earlier KASLR kernels. This patch sets the KERNEL_IMAGE_SIZE
default value to 1GB for those earlier kernels, and also adds a
new "--machdep kernel_image_size=<value>" option that can be
used to override the default KERNEL_IMAGE_SIZE value if necessary.
(anderson@redhat.com)
FADUMP-generated dumpfiles (Firmware Assisted Dump facility).
Without the patch, backtraces of those tasks may be of the form
"#0 [c0000000700b3a90] (null) at c0000000700b3b50 (unreliable)".
This patch uses and displays the ptregs register set saved in the
dumpfile header for the non-panicking active tasks.
(hbathini@linux.vnet.ibm.com)
display from generating a fatal session-killing error if relevant
kernel symbol names or data structures change in the future (again).
(anderson@redhat.com)
member names to be changed to "c_true" and "c_false", which fixes
build problems when an out-of-tree module defines "true" or "false".
(anderson@redhat.com)
the change in size of the module.taints flag from an int to a long,
while allowing for a kernel backport that keeps it as an int.
(anderson@redhat.com)
and later x86_64 kernels configured with CONFIG_RANDOMIZE_BASE, which
randomizes the unity-mapping PAGE_OFFSET value. Without the patch,
the crash session fails during session initialization with the error
message "crash: seek error: kernel virtual address: <address>
type: page_offset_base".
(anderson@redhat.com)
"taint/module: Clean up global and module taint flags handling".
Without the patch, when running against Linux 4.10-rc1 and later
kernels, the crash utility fails during session initialization with
the message "crash: invalid structure size: tnt".
(panand@redhat.com)
are configured with CONFIG_THREAD_INFO_IN_TASK. Without the patch,
the "bt" command will fail for active tasks in dumpfiles that were
generated by the kdump facility.
(takahiro.akashi@linaro.org)
which it isn't now since the internal machdep->pagesize is unsigned.
Without this patch, module loading fails during initialization on a
kernel that has a page size of 16KB, with messages that indicate
"please wait... (gathering module symbol data)" followed by
"crash: invalid size request: 0 type: pgd page".
(rabinv@axis.com)
running against a 32-bit MIPS ELF kdump or compressed kdump if a
per-cpu NT_PRSTATUS note cannot be be gathered from the dumpfile
header. Without the the patch, a segmentation violation occurs after
the message "WARNING: cannot find NT_PRSTATUS note for cpu: <number>"
is displayed.
(rabinv@axis.com)
if the kernel crashed while running a module's initcall. Without
the patch, the crash session fails during initialation with a message
similar to "crash: store_module_symbols_v2: total: 7 mcnt: 8".
(rabinv@axis.com)
which introduced the new slab management type OBJFREELIST_SLAB.
In this mode, the freelist can be an object, and if the slab is full,
there is no freelist. On the next free, an object is recycled to be
used as the freelist but not cleaned-up. This patch will go through
only known freed objects, and will prevent "kmem -S" errors that
indicate "invalid/corrupt freelist entry" on kernels configured
with CONFIG_SLAB.
(thgarnie@google.com)
to version 1.3, which adds support for Linux 4.6 and later ARM64
kernels, kernels configured with CONFIG_HARDENED_USERCOPY, and
S390X kernels use xlate_dev_mem_ptr() and unxlate_dev_mem_ptr()
instead of kmap() and kunmap().
(anderson@redhat.com)
for Linux 4.6 commit a7f8de168ace487fa7b88cb154e413cf40e87fc6, which
allows the ARM64 kernel image to be loaded anywhere in physical
memory. Without the patch, attempting to run live on an ARM64
Linux 4.6 and later kernel may display the warning message "WARNING:
cannot read linux_banner string", and then fails with the message
"crash: vmlinux and /dev/crash do not match!". Version 1.3 of the
crash driver is required, which introduces a new ioctl command that
retrieves the ARM64-only "kimage_voffset" value that is required for
virtual-to-physical address translation.
(anderson@redhat.com)
c9f932440b in this crash-7.1.7 release that added support for
the new CONFIG_THREAD_INFO_IN_TASK configuration, the backtrace of
active tasks can be incomplete.
(holzheu@linux.vnet.ibm.com)
create multiple independent ftrace buffers. At present, however,
the "trace.c" extension module is only able to extract the primary
buffer. This patch refactors the trace.c extension module so that
the global instance is passed around as a parameter rather than
accessing it directly, and then locates all of the available
instances and extracts the data from each of them.
(kyle.a.tomsic@gmail.com)
in Linux 4.9 and later kernels configured with CONFIG_RANDOMIZE_BASE.
Without the patch, the command shows a value of ffffea0000000000 next
to "KERNEL VMEMMAP BASE".
(anderson@redhat.com)
kernels configured with CONFIG_RANDOMIZE_BASE. Without the patch,
the crash session may fail during initialization with the message
"crash: vmlinux and vmcore do not match!".
(anderson@redhat.com)
x86_64 kernels that are configured with CONFIG_RANDOMIZE_BASE.
Depending upon the randomized starting address of the kernel text
and static data, a segmentation violation may occur during session
initialization, just after the patching of the gdb minimal_symbol
values message.
(anderson@redhat.com)
older kernels, each per-cpu init_tss.x86_hw_tss.ist[] array member),
is compared with its associated per-cpu orig_ist.ist[] array member,
ensure that both exception stack pointers have been initialized
(non-NULL) before printing a WARNING message if they don't match.
(anderson@redhat.com)
rewrote the X86_64 switch_to() code by embedding the __switch_to()
call inside a new __switch_to_asm() assembly code ENTRY() function.
Without the patch, the message "crash: cannot determine thread return
address" gets displayed during initialization, and the "bt" command
shows frame #0 starting at "schedule" instead of "__schedule".
(anderson@redhat.com)
dumpfiles:
(1) If ELF notes are not available, read them from the kernel's
crash_notes.
(2) If an online CPUs did not save its ELF notes, then adjust
the mapping of each ELF note to its CPU accordingly.
(rabinv@axis.com)
and c65eacbe290b8141554c71b2c94489e73ade8c8d, which have introduced a
new CONFIG_THREAD_INFO_IN_TASK configuration. This configuration
moves each task's thread_info structure from the base of its kernel
stack into its task_struct. Without the patch, the crash session
fails during initialization with the error "crash: invalid structure
member offset: thread_info_cpu".
(anderson@redhat.com)
whose device driver uses the blk-mq interface. Currently "dev -d"
always displays 0 in all fields for the blk-mq disk because blk-mq
does not increment/decrement request_list.count[2] on I/O creation
and I/O completion. The following values are used in blk-mq in such
situations:
- I/O creation: blk_mq_ctx.rq_dispatched[2]
- I/O completion: blk_mq_ctx.rq_completed[2]
So, we can get the counter of in-progress I/Os as follows:
in progress I/Os == rq_dispatched - rq_completed
This patch displays the result of above calculation for the disk.
It determines whether the device driver uses blk-mq if the
request_queue.mq_ops is not NULL. The "DRV" field is displayed as
"N/A(MQ)" if the value for in-flight in the device driver does not
exist for blk-mq.
(m.mizuma@jp.fujitsu.com)
KASLR. When KASLR is enabled on ARM64, a function call between a
module and the base kernel code will be done via a veneer (PLT) if
the displacement is more than +/-128MB. As a result, disassembled
code will show a branch to the in-module veneer location instead of
the in-kernel target location. To avoid confusion, the output of
the "dis" command will translate the veneer location to the target
location preceded by "plt:", for example, "<plt:printk>".
(takahiro.akashi@linaro.org)
as is done with 32-bit ARM. Without the patch, a crash session may
fail during the "gathering module symbol data" stage with a message
similar to "crash: store_module_symbols_v2: total: 15 mcnt: 16".
(takahiro.akashi@linaro.org)
3.15 and later kernels. In crash-7.1.6, the MEMBER_OFFSET() macro
has been improved so that it is able to recognize members of embedded
anonymous structures. However, the module's manner of recognizing
Linux 3.15 and later kernels depended upon MEMBER_OFFSET() failing
to handle anonymous members, and therefore the improvement prevented
the module from successfully loading.
(rabinv@axis.com)
that are not declared as "char *" types. Change two prior direct
callers of resizebuf() to use RESIZEBUF(), and fix two prior users of
RESIZEBUF() to correctly calculate the need to resize their buffers.
(anderson@redhat.com)
As both radix and hash MMU are supported in a single kernel on
Power ISA 3.0 based server processors, identify the current MMU
type and set page table index values accordingly. Also, in Linux
4.7 and later kernels, PPC64/BOOK3S uses the same masked bit values
in page table entries for 4K and 64K page sizes.
(hbathini@linux.vnet.ibm.com)
in which Thomas Gleixner redesigned the kernel timer mechanism to
switch to a non-cascading wheel. Without the patch, the "timer"
command fails with the message "timer: zero-size memory allocation!
(called from <address>)"
(anderson@redhat.com)
changes in kernel page table management accommodating it. This patch
series makes appropriate changes here to work for such kernels.
Also, this series fixes a few bugs along the way:
ppc64: fix vtop page translation for 4K pages
ppc64: Use kernel terminology for each level in 4-level page table
ppc64/book3s: address changes in kernel v4.5
ppc64/book3s: address change in page flags for PowerISA v3.0
ppc64: use physical addresses and unfold pud for 64K page size
ppc64/book3s: support big endian Linux page tables
The patches are needed for Linux v4.5 and later kernels on all
ppc64 hardware.
(hbathini@linux.vnet.ibm.com)
which renamed the x86_64 "init_tss" per-cpu variable to "cpu_tss".
Without the patch, the addresses of the 4 per-cpu exception stacks
cannot be determined, which causes backtraces that originate on
any of the per-cpu DOUBLEFAULT, NMI, DEBUG, or MCE stacks to be
truncated.
(anderson@redhat.com)
that are configured with CONFIG_RANDOMIZE_MEMORY, which randomizes
the base addresses of the kernel's unity-map address (PAGE_OFFSET),
and the vmalloc region. Without the patch, the crash utility fails
with a segmentation violation during session initialization.
(anderson@redhat.com)
each command's -s option, but instead of parsing gdb output, member
values are read directly from memory, so the command is much faster
for 1-, 2-, 4-, and 8-byte members.
(Alexandr_Terekhov@epam.com)
before falling back to ANON_MEMBER_OFFSET_INIT() in several known
cases of structure members that are contained within anonymous
structures.
(anderson@redhat.com)
contained within an anonymous structure or union. Without the patch,
it is necessary to parse the output of a discrete gdb "printf"
command to determine the offset of such a structure member.
(Alexandr_Terekhov@epam.com)
when the system has no swap pages at all. Without the patch, both
the PAGES and TOTAL columns show values of zero, but it confusingly
shows "100% of TOTAL SWAP", which upon first glance may seem to
indicate potential memory pressure.
(jsiddle@redhat.com)
initialization. In the unlikely case where the ordering of module
symbol name strings does not match the order of the kernel_symbol
structures, a faulty module symbol list entry may be created that
contains a bogus name string.
(sebastien.piechurski@bull.net)
to the kernel text symbol in a backtrace is contained within the
"[PC: <address> [<symbol+offset>]" line of an exception frame
dump. Without the patch, the reference will only be picked up if
the PC's hexadecimal address value is used.
(anderson@redhat.com)
