Mauro Carvalho Chehab fa2408a24f APEI/GHES: ensure that won't go past CPER allocated record
The logic at ghes_new() prevents allocating too large records, by
checking if they're bigger than GHES_ESTATUS_MAX_SIZE (currently, 64KB).
Yet, the allocation is done with the actual number of pages from the
CPER bios table location, which can be smaller.

Yet, a bad firmware could send data with a different size, which might
be bigger than the allocated memory, causing an OOPS:

    Unable to handle kernel paging request at virtual address fff00000f9b40000
    Mem abort info:
      ESR = 0x0000000096000007
      EC = 0x25: DABT (current EL), IL = 32 bits
      SET = 0, FnV = 0
      EA = 0, S1PTW = 0
      FSC = 0x07: level 3 translation fault
    Data abort info:
      ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000
      CM = 0, WnR = 0, TnD = 0, TagAccess = 0
      GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
    swapper pgtable: 4k pages, 52-bit VAs, pgdp=000000008ba16000
    [fff00000f9b40000] pgd=180000013ffff403, p4d=180000013fffe403, pud=180000013f85b403, pmd=180000013f68d403, pte=0000000000000000
    Internal error: Oops: 0000000096000007 [#1]  SMP
    Modules linked in:
    CPU: 0 UID: 0 PID: 303 Comm: kworker/0:1 Not tainted 6.19.0-rc1-00002-gda407d200220 #34 PREEMPT
    Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 02/02/2022
    Workqueue: kacpi_notify acpi_os_execute_deferred
    pstate: 214020c5 (nzCv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
    pc : hex_dump_to_buffer+0x30c/0x4a0
    lr : hex_dump_to_buffer+0x328/0x4a0
    sp : ffff800080e13880
    x29: ffff800080e13880 x28: ffffac9aba86f6a8 x27: 0000000000000083
    x26: fff00000f9b3fffc x25: 0000000000000004 x24: 0000000000000004
    x23: ffff800080e13905 x22: 0000000000000010 x21: 0000000000000083
    x20: 0000000000000001 x19: 0000000000000008 x18: 0000000000000010
    x17: 0000000000000001 x16: 00000007c7f20fec x15: 0000000000000020
    x14: 0000000000000008 x13: 0000000000081020 x12: 0000000000000008
    x11: ffff800080e13905 x10: ffff800080e13988 x9 : 0000000000000000
    x8 : 0000000000000000 x7 : 0000000000000001 x6 : 0000000000000020
    x5 : 0000000000000030 x4 : 00000000fffffffe x3 : 0000000000000000
    x2 : ffffac9aba78c1c8 x1 : ffffac9aba76d0a8 x0 : 0000000000000008
    Call trace:
     hex_dump_to_buffer+0x30c/0x4a0 (P)
     print_hex_dump+0xac/0x170
     cper_estatus_print_section+0x90c/0x968
     cper_estatus_print+0xf0/0x158
     __ghes_print_estatus+0xa0/0x148
     ghes_proc+0x1bc/0x220
     ghes_notify_hed+0x5c/0xb8
     notifier_call_chain+0x78/0x148
     blocking_notifier_call_chain+0x4c/0x80
     acpi_hed_notify+0x28/0x40
     acpi_ev_notify_dispatch+0x50/0x80
     acpi_os_execute_deferred+0x24/0x48
     process_one_work+0x15c/0x3b0
     worker_thread+0x2d0/0x400
     kthread+0x148/0x228
     ret_from_fork+0x10/0x20
    Code: 6b14033f 540001ad a94707e2 f100029f (b8747b44)
    ---[ end trace 0000000000000000 ]---

Prevent that by taking the actual allocated are into account when
checking for CPER length.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Subject tweaks ]
Link: https://patch.msgid.link/4e70310a816577fabf37d94ed36cde4ad62b1e0a.1767871950.git.mchehab+huawei@kernel.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2026-01-14 17:04:33 +01:00
2022-09-28 09:02:20 +02:00
2025-02-19 14:53:27 -07:00
2026-01-04 14:41:55 -08:00

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

The Linux kernel is the core of any Linux operating system. It manages hardware,
system resources, and provides the fundamental services for all other software.

Quick Start
-----------

* Report a bug: See Documentation/admin-guide/reporting-issues.rst
* Get the latest kernel: https://kernel.org
* Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst
* Join the community: https://lore.kernel.org/

Essential Documentation
-----------------------

All users should be familiar with:

* Building requirements: Documentation/process/changes.rst
* Code of Conduct: Documentation/process/code-of-conduct.rst
* License: See COPYING

Documentation can be built with make htmldocs or viewed online at:
https://www.kernel.org/doc/html/latest/


Who Are You?
============

Find your role below:

* New Kernel Developer - Getting started with kernel development
* Academic Researcher - Studying kernel internals and architecture
* Security Expert - Hardening and vulnerability analysis
* Backport/Maintenance Engineer - Maintaining stable kernels
* System Administrator - Configuring and troubleshooting
* Maintainer - Leading subsystems and reviewing patches
* Hardware Vendor - Writing drivers for new hardware
* Distribution Maintainer - Packaging kernels for distros


For Specific Users
==================

New Kernel Developer
--------------------

Welcome! Start your kernel development journey here:

* Getting Started: Documentation/process/development-process.rst
* Your First Patch: Documentation/process/submitting-patches.rst
* Coding Style: Documentation/process/coding-style.rst
* Build System: Documentation/kbuild/index.rst
* Development Tools: Documentation/dev-tools/index.rst
* Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst
* Core APIs: Documentation/core-api/index.rst

Academic Researcher
-------------------

Explore the kernel's architecture and internals:

* Researcher Guidelines: Documentation/process/researcher-guidelines.rst
* Memory Management: Documentation/mm/index.rst
* Scheduler: Documentation/scheduler/index.rst
* Networking Stack: Documentation/networking/index.rst
* Filesystems: Documentation/filesystems/index.rst
* RCU (Read-Copy Update): Documentation/RCU/index.rst
* Locking Primitives: Documentation/locking/index.rst
* Power Management: Documentation/power/index.rst

Security Expert
---------------

Security documentation and hardening guides:

* Security Documentation: Documentation/security/index.rst
* LSM Development: Documentation/security/lsm-development.rst
* Self Protection: Documentation/security/self-protection.rst
* Reporting Vulnerabilities: Documentation/process/security-bugs.rst
* CVE Procedures: Documentation/process/cve.rst
* Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst
* Security Features: Documentation/userspace-api/seccomp_filter.rst

Backport/Maintenance Engineer
-----------------------------

Maintain and stabilize kernel versions:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* Backporting Guide: Documentation/process/backporting.rst
* Applying Patches: Documentation/process/applying-patches.rst
* Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git for Maintainers: Documentation/maintainer/configure-git.rst

System Administrator
--------------------

Configure, tune, and troubleshoot Linux systems:

* Admin Guide: Documentation/admin-guide/index.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst
* Tracing/Debugging: Documentation/trace/index.rst
* Performance Security: Documentation/admin-guide/perf-security.rst
* Hardware Monitoring: Documentation/hwmon/index.rst

Maintainer
----------

Lead kernel subsystems and manage contributions:

* Maintainer Handbook: Documentation/maintainer/index.rst
* Pull Requests: Documentation/maintainer/pull-requests.rst
* Managing Patches: Documentation/maintainer/modifying-patches.rst
* Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst
* Development Process: Documentation/process/maintainer-handbooks.rst
* Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst
* Git Configuration: Documentation/maintainer/configure-git.rst

Hardware Vendor
---------------

Write drivers and support new hardware:

* Driver API Guide: Documentation/driver-api/index.rst
* Driver Model: Documentation/driver-api/driver-model/driver.rst
* Device Drivers: Documentation/driver-api/infrastructure.rst
* Bus Types: Documentation/driver-api/driver-model/bus.rst
* Device Tree Bindings: Documentation/devicetree/bindings/
* Power Management: Documentation/driver-api/pm/index.rst
* DMA API: Documentation/core-api/dma-api.rst

Distribution Maintainer
-----------------------

Package and distribute the kernel:

* Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst
* ABI Documentation: Documentation/ABI/README
* Kernel Configuration: Documentation/kbuild/kconfig.rst
* Module Signing: Documentation/admin-guide/module-signing.rst
* Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst
* Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst



Communication and Support
=========================

* Mailing Lists: https://lore.kernel.org/
* IRC: #kernelnewbies on irc.oftc.net
* Bugzilla: https://bugzilla.kernel.org/
* MAINTAINERS file: Lists subsystem maintainers and mailing lists
* Email Clients: Documentation/process/email-clients.rst
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