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Zheng Yejian f3f9f42232 kallsyms: Fix wrong "big" kernel symbol type read from procfs
Currently when the length of a symbol is longer than 0x7f characters,
its type shown in /proc/kallsyms can be incorrect.

I found this issue when reading the code, but it can be reproduced by
following steps:

  1. Define a function which symbol length is 130 characters:

    #define X13(x) x##x##x##x##x##x##x##x##x##x##x##x##x
    static noinline void X13(x123456789)(void)
    {
        printk("hello world\n");
    }

  2. The type in vmlinux is 't':

    $ nm vmlinux | grep x123456
    ffffffff816290f0 t x123456789x123456789x123456789x12[...]

  3. Then boot the kernel, the type shown in /proc/kallsyms becomes 'g'
     instead of the expected 't':

    # cat /proc/kallsyms | grep x123456
    ffffffff816290f0 g x123456789x123456789x123456789x12[...]

The root cause is that, after commit 73bbb94466 ("kallsyms: support
"big" kernel symbols"), ULEB128 was used to encode symbol name length.
That is, for "big" kernel symbols of which name length is longer than
0x7f characters, the length info is encoded into 2 bytes.

kallsyms_get_symbol_type() expects to read the first char of the
symbol name which indicates the symbol type. However, due to the
"big" symbol case not being handled, the symbol type read from
/proc/kallsyms may be wrong, so handle it properly.

Cc: stable@vger.kernel.org
Fixes: 73bbb94466 ("kallsyms: support "big" kernel symbols")
Signed-off-by: Zheng Yejian <zhengyejian@huaweicloud.com>
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20241011143853.3022643-1-zhengyejian@huaweicloud.com
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2025-11-24 16:56:24 +01:00
Documentation docs: rust: quick-start: add Debian 13 (Trixie) 2025-11-04 20:21:15 +01:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
arch - Reset the why-the-system-rebooted register on AMD to avoid stale bits 2025-10-19 04:41:27 -10:00
block block-6.18-20251016 2025-10-17 08:31:26 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push contains the following changes: 2025-10-10 08:56:16 -07:00
drivers rust: rbtree: add immutable cursor 2025-11-16 21:56:57 +01:00
fs Description for this pull request: 2025-10-18 07:23:59 -10:00
include hid-for-linus-2025101701 2025-10-18 08:18:18 -10:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/rw: check for NULL io_br_sel when putting a buffer 2025-10-15 13:38:53 -06:00
ipc namespace-6.18-rc1 2025-09-29 11:20:29 -07:00
kernel kallsyms: Fix wrong "big" kernel symbol type read from procfs 2025-11-24 16:56:24 +01:00
lib lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt 2025-10-07 13:48:56 -07:00
mm slab: reset slab->obj_ext when freeing and it is OBJEXTS_ALLOC_FAIL 2025-10-16 15:16:45 +02:00
net bpf-fixes 2025-10-18 08:00:43 -10:00
rust rust: num: bounded: rename `try_into_bitint` to `try_into_bounded` 2025-11-24 16:38:23 +01:00
samples samples: rust: debugfs: use `core::ffi::CStr` method names 2025-10-20 04:04:23 +02:00
scripts rust: allow `clippy::disallowed_names` for doctests 2025-11-17 22:53:27 +01:00
security integrity-v6.18 2025-10-05 10:48:33 -07:00
sound ALSA: hda/realtek: Fix mute led for HP Omen 17-cb0xxx 2025-10-17 16:37:21 +02:00
tools hid-for-linus-2025101701 2025-10-18 08:18:18 -10:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM x86 fixes for 6.18: 2025-10-18 10:25:43 +02:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about `clippy::disallowed_macros` configuration 2025-05-07 00:11:47 +02:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap Including fixes from CAN 2025-10-16 09:41:21 -07:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add `.rustfmt.toml` 2022-09-28 09:02:20 +02:00
COPYING
CREDITS USB/Thunderbolt changes for 6.18-rc1 2025-10-04 16:07:08 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: add entry for the Rust `num` module 2025-11-19 00:22:30 +01:00
Makefile Linux 6.18-rc2 2025-10-19 15:19:16 -10:00
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.