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Song Liu 139560e8b9 livepatch: Match old_sympos 0 and 1 in klp_find_func()
When there is only one function of the same name, old_sympos of 0 and 1
are logically identical. Match them in klp_find_func().

This is to avoid a corner case with different toolchain behavior.

In this specific issue, two versions of kpatch-build were used to
build livepatch for the same kernel. One assigns old_sympos == 0 for
unique local functions, the other assigns old_sympos == 1 for unique
local functions. Both versions work fine by themselves. (PS: This
behavior change was introduced in a downstream version of kpatch-build.
This change does not exist in upstream kpatch-build.)

However, during livepatch upgrade (with the replace flag set) from a
patch built with one version of kpatch-build to the same fix built with
the other version of kpatch-build, livepatching fails with errors like:

[   14.218706] sysfs: cannot create duplicate filename 'xxx/somefunc,1'
...
[   14.219466] Call Trace:
[   14.219468]  <TASK>
[   14.219469]  dump_stack_lvl+0x47/0x60
[   14.219474]  sysfs_warn_dup.cold+0x17/0x27
[   14.219476]  sysfs_create_dir_ns+0x95/0xb0
[   14.219479]  kobject_add_internal+0x9e/0x260
[   14.219483]  kobject_add+0x68/0x80
[   14.219485]  ? kstrdup+0x3c/0xa0
[   14.219486]  klp_enable_patch+0x320/0x830
[   14.219488]  patch_init+0x443/0x1000 [ccc_0_6]
[   14.219491]  ? 0xffffffffa05eb000
[   14.219492]  do_one_initcall+0x2e/0x190
[   14.219494]  do_init_module+0x67/0x270
[   14.219496]  init_module_from_file+0x75/0xa0
[   14.219499]  idempotent_init_module+0x15a/0x240
[   14.219501]  __x64_sys_finit_module+0x61/0xc0
[   14.219503]  do_syscall_64+0x5b/0x160
[   14.219505]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[   14.219507] RIP: 0033:0x7f545a4bd96d
...
[   14.219516] kobject: kobject_add_internal failed for somefunc,1 with
    -EEXIST, don't try to register things with the same name ...

This happens because klp_find_func() thinks somefunc with old_sympos==0
is not the same as somefunc with old_sympos==1, and klp_add_object_nops
adds another xxx/func,1 to the list of functions to patch.

Signed-off-by: Song Liu <song@kernel.org>
Acked-by: Josh Poimboeuf <jpoimboe@kernel.org>
[pmladek@suse.com: Fixed some typos.]
Reviewed-by: Petr Mladek <pmladek@suse.com>
Tested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
History 2025-10-15 14:47:19 +02:00
arch linux_kselftest-kunit-6.15-rc1 2025-03-27 19:06:07 -07:00
block for-6.15/block-20250322 2025-03-26 18:08:55 -07:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto for-6.15/block-20250322 2025-03-26 18:08:55 -07:00
Documentation Livepatching changes for 6.15 2025-03-27 19:26:10 -07:00
drivers printk changes for 6.15 2025-03-27 19:22:24 -07:00
fs Ext4 bug fixes and cleanups, including: 2025-03-27 13:27:08 -07:00
include printk changes for 6.15 2025-03-27 19:22:24 -07:00
init [ Merge note: this pull request depends on you having merged 2025-03-24 22:06:11 -07:00
io_uring Networking changes for 6.15. 2025-03-26 21:48:21 -07:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel livepatch: Match old_sympos 0 and 1 in klp_find_func() 2025-10-15 14:47:19 +02:00
lib linux_kselftest-kunit-6.15-rc1 2025-03-27 19:06:07 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm f2fs-for-6.15-rc1 2025-03-27 12:55:54 -07:00
net Networking changes for 6.15. 2025-03-26 21:48:21 -07:00
rust lsm/stable-6.15 PR 20250323 2025-03-25 15:44:19 -07:00
samples hardening updates for v6.15-rc1 2025-03-24 15:18:08 -07:00
scripts tracing updates for v6.15: 2025-03-27 16:22:12 -07:00
security Summary 2025-03-26 21:02:05 -07:00
sound hid-for-linus-2025032601 2025-03-26 10:05:43 -07:00
tools Livepatching changes for 6.15 2025-03-27 19:26:10 -07:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-03-25 14:22:07 -07:00
.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 2025-01-10 00:17:25 +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 MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore rust: use host dylib naming convention to support macOS 2025-01-10 01:01:24 +01:00
.mailmap lsm/stable-6.15 PR 20250323 2025-03-25 15:44:19 -07:00
.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: update bridge entry 2025-03-21 18:24:07 +01:00
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 tracing updates for v6.15: 2025-03-27 16:22:12 -07:00
Makefile [ Merge note: this pull request depends on you having merged 2025-03-24 22:06:11 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.