[syzbot] [modules?] KMSAN: uninit-value in __request_module (6)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: febbc555cf0f Merge tag 'nfsd-6.14-1' of git://git.kernel.o..
git tree: upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=137a78e4580000
kernel config: https://syzkaller.appspot.com/x/.config?x=48f90cac5eea091a
dashboard link: https://syzkaller.appspot.com/bug?extid=1fcd957a82e3a1baa94d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=177a78e4580000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16adc3f8580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f90f94285615/disk-febbc555.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/b8a8bb66806c/vmlinux-febbc555.xz
kernel image: https://storage.googleapis.com/syzbot-assets/c8af6c511559/bzImage-febbc555.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1fcd95...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:633 [inline]
BUG: KMSAN: uninit-value in string+0x3ec/0x5f0 lib/vsprintf.c:714
string_nocheck lib/vsprintf.c:633 [inline]
string+0x3ec/0x5f0 lib/vsprintf.c:714
vsnprintf+0xa5d/0x1960 lib/vsprintf.c:2843
__request_module+0x252/0x9f0 kernel/module/kmod.c:149
team_mode_get drivers/net/team/team_core.c:480 [inline]
team_change_mode drivers/net/team/team_core.c:607 [inline]
team_mode_option_set+0x437/0x970 drivers/net/team/team_core.c:1401
team_option_set drivers/net/team/team_core.c:375 [inline]
team_nl_options_set_doit+0x1339/0x1f90 drivers/net/team/team_core.c:2661
genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x1214/0x12c0 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2543
genl_rcv+0x40/0x60 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1322 [inline]
netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1348
netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1892
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:733
____sys_sendmsg+0x877/0xb60 net/socket.c:2573
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2627
__sys_sendmsg net/socket.c:2659 [inline]
__do_sys_sendmsg net/socket.c:2664 [inline]
__se_sys_sendmsg net/socket.c:2662 [inline]
__x64_sys_sendmsg+0x212/0x3c0 net/socket.c:2662
x64_sys_call+0x2ed6/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
slab_post_alloc_hook mm/slub.c:4121 [inline]
slab_alloc_node mm/slub.c:4164 [inline]
kmem_cache_alloc_node_noprof+0x907/0xe00 mm/slub.c:4216
kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:587
__alloc_skb+0x363/0x7b0 net/core/skbuff.c:678
alloc_skb include/linux/skbuff.h:1331 [inline]
netlink_alloc_large_skb+0x1b4/0x280 net/netlink/af_netlink.c:1196
netlink_sendmsg+0xa96/0x11e0 net/netlink/af_netlink.c:1867
sock_sendmsg_nosec net/socket.c:718 [inline]
__sock_sendmsg+0x30f/0x380 net/socket.c:733
____sys_sendmsg+0x877/0xb60 net/socket.c:2573
___sys_sendmsg+0x28d/0x3c0 net/socket.c:2627
__sys_sendmsg net/socket.c:2659 [inline]
__do_sys_sendmsg net/socket.c:2664 [inline]
__se_sys_sendmsg net/socket.c:2662 [inline]
__x64_sys_sendmsg+0x212/0x3c0 net/socket.c:2662
x64_sys_call+0x2ed6/0x3c30 arch/x86/include/generated/asm/syscalls_64.h:47
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xcd/0x1e0 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 5814 Comm: syz-executor989 Not tainted 6.14.0-rc2-syzkaller-00034-gfebbc555cf0f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup

[Petr Pavlu]

For the record in linux-modules, Eric Dumazet posted a fix for this
issue at:
https://lore.kernel.org/netdev/20250212134928.1...@google.com/

-- Petr

[syzbot]

For archival purposes, forwarding an incoming command email to
linux-...@vger.kernel.org, syzkall...@googlegroups.com.

***

Subject:
Author: purvay...@gmail.com

#syz test

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

ld: lib/vsprintf.o:lib/vsprintf.c:625: multiple definition of `s'; mm/slub.o:mm/slub.c:4075: first defined here


Tested on:

commit: 4dc1d1be Merge tag 'mfd-fixes-6.14' of git://git.kerne..
git tree: upstream

kernel config: https://syzkaller.appspot.com/x/.config?x=48f90cac5eea091a
dashboard link: https://syzkaller.appspot.com/bug?extid=1fcd957a82e3a1baa94d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=122bc9b0580000

[syzbot]

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KMSAN: uninit-value in __request_module

=====================================================
BUG: KMSAN: uninit-value in string_nocheck lib/vsprintf.c:636 [inline]
BUG: KMSAN: uninit-value in string+0x3ec/0x5f0 lib/vsprintf.c:717
string_nocheck lib/vsprintf.c:636 [inline]
string+0x3ec/0x5f0 lib/vsprintf.c:717
vsnprintf+0xa5d/0x1960 lib/vsprintf.c:2846

CPU: 0 UID: 0 PID: 6614 Comm: syz.0.16 Not tainted 6.14.0-rc2-syzkaller-gab68d7eb7b1a-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
=====================================================

Tested on:

commit: ab68d7eb Merge tag 'loongarch-fixes-6.14-1' of git://g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=122893f8580000

kernel config: https://syzkaller.appspot.com/x/.config?x=48f90cac5eea091a
dashboard link: https://syzkaller.appspot.com/bug?extid=1fcd957a82e3a1baa94d
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=13a721a4580000