No description
  • C 96.8%
  • Assembly 0.9%
  • Rust 0.7%
  • Shell 0.6%
  • Python 0.5%
  • Other 0.3%
Find a file
Zhichi Lin 08bd4c46d5 scs: fix a wrong parameter in __scs_magic
__scs_magic() needs a 'void *' variable, but a 'struct task_struct *' is
given.  'task_scs(tsk)' is the starting address of the task's shadow call
stack, and '__scs_magic(task_scs(tsk))' is the end address of the task's
shadow call stack.  Here should be '__scs_magic(task_scs(tsk))'.

The user-visible effect of this bug is that when CONFIG_DEBUG_STACK_USAGE
is enabled, the shadow call stack usage checking function
(scs_check_usage) would scan an incorrect memory range.  This could lead
to:

1. **Inaccurate stack usage reporting**: The function would calculate
   wrong usage statistics for the shadow call stack, potentially showing
   incorrect value in kmsg.

2. **Potential kernel crash**: If the value of __scs_magic(tsk)is
   greater than that of __scs_magic(task_scs(tsk)), the for loop may
   access unmapped memory, potentially causing a kernel panic.  However,
   this scenario is unlikely because task_struct is allocated via the slab
   allocator (which typically returns lower addresses), while the shadow
   call stack returned by task_scs(tsk) is allocated via vmalloc(which
   typically returns higher addresses).

However, since this is purely a debugging feature
(CONFIG_DEBUG_STACK_USAGE), normal production systems should be not
unaffected.  The bug only impacts developers and testers who are actively
debugging stack usage with this configuration enabled.

Link: https://lkml.kernel.org/r/20251011082222.12965-1-zhichi.lin@vivo.com
Fixes: 5bbaf9d1fc ("scs: Add support for stack usage debugging")
Signed-off-by: Jiyuan Xie <xiejiyuan@vivo.com>
Signed-off-by: Zhichi Lin <zhichi.lin@vivo.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Marco Elver <elver@google.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yee Lee <yee.lee@mediatek.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
History 2025-11-12 10:00:13 -08:00
arch
block
certs
crypto
Documentation
drivers
fs
include
init
io_uring
ipc
kernel
lib
LICENSES
mm
net
rust
samples
scripts
security
sound
tools
usr
virt
.clang-format
.clippy.toml
.cocciconfig
.editorconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
.pylintrc
.rustfmt.toml
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS
Makefile
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.