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Sourabh Jain d8c573471e powerpc/kdump: Fix size calculation for hot-removed memory ranges 
[ Upstream commit 7afe2383ef ]

The elfcorehdr segment in the kdump image stores information about the
memory regions (called crash memory ranges) that the kdump kernel must
capture.

When a memory hot-remove event occurs, the kernel regenerates the
elfcorehdr for the currently loaded kdump image to remove the
hot-removed memory from the crash memory ranges.

Call chain:
remove_mem_range()
update_crash_elfcorehdr()
arch_crash_handle_hotplug_event()
crash_handle_hotplug_event()

While removing the hot-removed memory from the crash memory ranges in
remove_mem_range(), if the removed memory lies within an existing crash
range, that range is split into two. During this split, the size of the
second range was being calculated incorrectly.

This leads to dump capture failure with makedumpfile with below error:

$ makedumpfile -l -d 31 /proc/vmcore /tmp/vmcore

readpage_elf: Attempt to read non-existent page at 0xbbdab0000.
readmem: type_addr: 0, addr:c000000bbdab7f00, size:16
validate_mem_section: Can't read mem_section array.
readpage_elf: Attempt to read non-existent page at 0xbbdab0000.
readmem: type_addr: 0, addr:c000000bbdab7f00, size:8
get_mm_sparsemem: Can't get the address of mem_section.

The updated crash memory range in PT_LOAD entry is holding incorrect
data (checkout FileSiz and MemSiz):

readelf -a /proc/vmcore
<snip...>
  Type           Offset             VirtAddr           PhysAddr
                 FileSiz            MemSiz              Flags  Align
  LOAD           0x0000000b013d0000 0xc000000b80000000 0x0000000b80000000
                 0xffffffffc0000000 0xffffffffc0000000  RWE    0x0
<snip...>

Update the size calculation for the new crash memory range to fix this
issue.

Note: This problem will not occur if the kdump kernel is loaded or
reloaded after a memory hot-remove operation.

Fixes: 849599b702 ("powerpc/crash: add crash memory hotplug support")
Reported-by: Shirisha G <shirisha@linux.ibm.com>
Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20251105033941.1752287-1-sourabhjain@linux.ibm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2025-12-18 13:54:56 +01:00
arch powerpc/kdump: Fix size calculation for hot-removed memory ranges 2025-12-18 13:54:56 +01:00
block block/mq-deadline: Switch back to a single dispatch list 2025-12-18 13:54:45 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: asymmetric_keys - prevent overflow in asymmetric_key_generate_id 2025-12-18 13:54:47 +01:00
Documentation dt-bindings: PCI: amlogic: Fix the register name of the DBI region 2025-12-18 13:54:55 +01:00
drivers cpufreq/amd-pstate: Call cppc_set_auto_sel() only for online CPUs 2025-12-18 13:54:56 +01:00
fs ntfs3: init run lock for extend inode 2025-12-18 13:54:56 +01:00
include perf: Remove get_perf_callchain() init_nr argument 2025-12-18 13:54:49 +01:00
init init: handle bootloader identifier in kernel parameters 2025-10-19 16:33:50 +02:00
io_uring io_uring/napi: fix io_napi_entry RCU accesses 2025-11-24 10:36:06 +01:00
ipc ipc: fix to protect IPCS lookups using RCU 2025-06-27 11:11:22 +01:00
kernel locktorture: Fix memory leak in param_set_cpumask() 2025-12-18 13:54:54 +01:00
lib maple_tree: fix tracepoint string pointers 2025-12-01 11:43:39 +01:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm mm/huge_memory: fix NULL pointer deference when splitting folio 2025-12-07 06:25:02 +09:00
net sctp: Defer SCTP_DBG_OBJCNT_DEC() to sctp_destroy_sock(). 2025-12-18 13:54:48 +01:00
rust rust: kbuild: workaround rustdoc doctests modifier bug 2025-11-24 10:36:07 +01:00
samples samples: work around glibc redefining some of our defines wrong 2025-12-12 18:37:21 +01:00
scripts kconfig/nconf: Initialize the default locale at startup 2025-12-01 11:43:36 +01:00
security smack: fix bug: setting task label silently ignores input garbage 2025-12-18 13:54:40 +01:00
sound ALSA: usb-audio: Add native DSD quirks for PureAudio DAC series 2025-12-12 18:37:20 +01:00
tools libbpf: Fix parsing of multi-split BTF 2025-12-18 13:54:53 +01:00
usr kbuild: uapi: Strip comments before size type check 2025-11-13 15:34:35 -05:00
virt KVM: guest_memfd: Remove bindings on memslot deletion when gmem is dying 2025-11-24 10:36:06 +01:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-08-01 09:48:44 +01:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: introduce .clippy.toml 2025-03-13 13:01:42 +01:00
.mailmap mailmap: add entry for Thorsten Blum 2024-11-07 14:14:59 -08:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: Remove self from DSA entry 2024-11-03 12:52:38 -08:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS staging: rtl8712: Remove driver using deprecated API wext 2025-12-07 06:25:02 +09:00
Makefile Linux 6.12.62 2025-12-12 18:37:22 +01:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.