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Kuniyuki Iwashima f0cc3777b2 net: Fix wild-memory-access in __register_pernet_operations() when CONFIG_NET_NS=n.
kernel test robot reported the splat below. [0]

Before commit fed176bf31 ("net: Add ops_undo_single for module
load/unload."), if CONFIG_NET_NS=n, ops was linked to pernet_list
only when init_net had not been initialised, and ops was unlinked
from pernet_list only under the same condition.

Let's say an ops is loaded before the init_net setup but unloaded
after that.  Then, the ops remains in pernet_list, which seems odd.

The cited commit added ops_undo_single(), which calls list_add() for
ops to link it to a temporary list, so a minor change was added to
__register_pernet_operations() and __unregister_pernet_operations()
under CONFIG_NET_NS=n to avoid the pernet_list corruption.

However, the corruption must have been left as is.

When CONFIG_NET_NS=n, pernet_list was used to keep ops registered
before the init_net setup, and after that, pernet_list was not used
at all.

This was because some ops annotated with __net_initdata are cleared
out of memory at some point during boot.

Then, such ops is initialised by POISON_FREE_INITMEM (0xcc), resulting
in that ops->list.{next,prev} suddenly switches from a valid pointer
to a weird value, 0xcccccccccccccccc.

To avoid such wild memory access, let's allow the pernet_list
corruption for CONFIG_NET_NS=n.

[0]:
Oops: general protection fault, probably for non-canonical address 0xf999959999999999: 0000 [#1] SMP KASAN NOPTI
KASAN: maybe wild-memory-access in range [0xccccccccccccccc8-0xcccccccccccccccf]
CPU: 2 UID: 0 PID: 346 Comm: modprobe Not tainted 6.15.0-rc1-00294-ga4cba7e98e35 #85 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014
RIP: 0010:__list_add_valid_or_report (lib/list_debug.c:32)
Code: 48 c1 ea 03 80 3c 02 00 0f 85 5a 01 00 00 49 39 74 24 08 0f 85 83 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 1f 01 00 00 4c 39 26 0f 85 ab 00 00 00 4c 39 ee
RSP: 0018:ff11000135b87830 EFLAGS: 00010a07
RAX: dffffc0000000000 RBX: ffffffffc02223c0 RCX: ffffffff8406fcc2
RDX: 1999999999999999 RSI: cccccccccccccccc RDI: ffffffffc02223c0
RBP: ffffffff86064e40 R08: 0000000000000001 R09: fffffbfff0a9f5b5
R10: ffffffff854fadaf R11: 676552203a54454e R12: ffffffff86064e40
R13: ffffffffc02223c0 R14: ffffffff86064e48 R15: 0000000000000021
FS:  00007f6fb0d9e1c0(0000) GS:ff11000858ea0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6fb0eda580 CR3: 0000000122fec005 CR4: 0000000000771ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
PKRU: 55555554
Call Trace:
 <TASK>
 register_pernet_operations (./include/linux/list.h:150 (discriminator 5) ./include/linux/list.h:183 (discriminator 5) net/core/net_namespace.c:1315 (discriminator 5) net/core/net_namespace.c:1359 (discriminator 5))
 register_pernet_subsys (net/core/net_namespace.c:1401)
 inet6_init (net/ipv6/af_inet6.c:535) ipv6
 do_one_initcall (init/main.c:1257)
 do_init_module (kernel/module/main.c:2942)
 load_module (kernel/module/main.c:3409)
 init_module_from_file (kernel/module/main.c:3599)
 idempotent_init_module (kernel/module/main.c:3611)
 __x64_sys_finit_module (./include/linux/file.h:62 ./include/linux/file.h:83 kernel/module/main.c:3634 kernel/module/main.c:3621 kernel/module/main.c:3621)
 do_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)
 entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
 RIP: 0033:0x7f6fb0df7e5d
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 73 9f 1b 00 f7 d8 64 89 01 48
RSP: 002b:00007fffdc6a8968 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
RAX: ffffffffffffffda RBX: 000055b535721b70 RCX: 00007f6fb0df7e5d
RDX: 0000000000000000 RSI: 000055b51e44aa2a RDI: 0000000000000004
RBP: 0000000000040000 R08: 0000000000000000 R09: 000055b535721b30
R10: 0000000000000004 R11: 0000000000000246 R12: 000055b51e44aa2a
R13: 000055b535721bf0 R14: 000055b5357220b0 R15: 0000000000000000
 </TASK>
Modules linked in: ipv6(+) crc_ccitt

Fixes: fed176bf31 ("net: Add ops_undo_single for module load/unload.")
Reported-by: kernel test robot <oliver.sang@intel.com>
Closes: https://lore.kernel.org/oe-lkp/202504181511.1c3f23e4-lkp@intel.com
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250418215025.87871-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-04-23 16:24:56 -07:00
arch Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-04-17 12:26:50 -07:00
block treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: ahash - Disable request chaining 2025-04-12 09:33:09 +08:00
Documentation netlink: specs: rt-rule: add C naming info 2025-04-23 16:07:16 -07:00
drivers net: stmmac: dwc-qos: calibrate tegra with mdio bus idle 2025-04-23 16:01:22 -07:00
fs Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-04-17 12:26:50 -07:00
include xdp: create locked/unlocked instances of xdp redirect target setters 2025-04-22 19:57:56 -07:00
init Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
io_uring io_uring/kbuf: reject zero sized provided buffers 2025-04-07 07:51:23 -06:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel bpf-next-for-netdev 2025-04-21 18:51:08 -07:00
lib 31 hotfixes. 9 are cc:stable and the remainder address post-6.15 issues 2025-04-16 20:07:32 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-04-17 12:26:50 -07:00
net net: Fix wild-memory-access in __register_pernet_operations() when CONFIG_NET_NS=n. 2025-04-23 16:24:56 -07:00
rust Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
samples Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2025-04-17 12:26:50 -07:00
scripts net: Retire DCCP socket. 2025-04-11 18:58:10 -07:00
security net: Retire DCCP socket. 2025-04-11 18:58:10 -07:00
sound ASoC: Fixes for v6.15 2025-04-11 15:51:19 +02:00
tools netlink: specs: allow header properties for attribute sets 2025-04-23 16:07:15 -07:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-04-08 13:47:55 -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 kbuild: Create intermediate vmlinux build with relocations preserved 2025-03-17 00:29:50 +09:00
.mailmap sound fixes for 6.15-rc3 2025-04-17 10:14:51 -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 Including fixes from netfilter. 2025-04-04 09:15:35 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS MAINTAINERS: Add entry for Renesas RZ/V2H(P) DWMAC GBETH glue layer driver 2025-04-22 18:49:20 -07:00
Makefile Linux 6.15-rc2 2025-04-13 11:54:49 -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.