[syzbot] [net?] KMSAN: uninit-value in tcf_ct_flow_table_get

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    2c9b3512402e Merge tag 'for-linus' of git://git.kernel.org..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=11d643fd980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=6bfb33a8ad10458f
dashboard link: https://syzkaller.appspot.com/bug?extid=1b5e4e187cc586d05ea0
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=17495ec3980000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=126076b5980000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/f8543636ba6c/disk-2c9b3512.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/403c612b7ac5/vmlinux-2c9b3512.xz
kernel image: https://storage.googleapis.com/syzbot-assets/88dc686d170a/bzImage-2c9b3512.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1b5e4e187cc586d05ea0@xxxxxxxxxxxxxxxxxxxxxxxxx

=====================================================
BUG: KMSAN: uninit-value in rht_ptr_rcu include/linux/rhashtable.h:376 [inline]
BUG: KMSAN: uninit-value in __rhashtable_lookup include/linux/rhashtable.h:607 [inline]
BUG: KMSAN: uninit-value in rhashtable_lookup include/linux/rhashtable.h:646 [inline]
BUG: KMSAN: uninit-value in rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline]
BUG: KMSAN: uninit-value in tcf_ct_flow_table_get+0x611/0x2260 net/sched/act_ct.c:329
 rht_ptr_rcu include/linux/rhashtable.h:376 [inline]
 __rhashtable_lookup include/linux/rhashtable.h:607 [inline]
 rhashtable_lookup include/linux/rhashtable.h:646 [inline]
 rhashtable_lookup_fast include/linux/rhashtable.h:672 [inline]
 tcf_ct_flow_table_get+0x611/0x2260 net/sched/act_ct.c:329
 tcf_ct_init+0xa67/0x2890 net/sched/act_ct.c:1408
 tcf_action_init_1+0x6cc/0xb30 net/sched/act_api.c:1425
 tcf_action_init+0x458/0xf00 net/sched/act_api.c:1488
 tcf_action_add net/sched/act_api.c:2061 [inline]
 tc_ctl_action+0x4be/0x19d0 net/sched/act_api.c:2118
 rtnetlink_rcv_msg+0x12fc/0x1410 net/core/rtnetlink.c:6647
 netlink_rcv_skb+0x375/0x650 net/netlink/af_netlink.c:2550
 rtnetlink_rcv+0x34/0x40 net/core/rtnetlink.c:6665
 netlink_unicast_kernel net/netlink/af_netlink.c:1331 [inline]
 netlink_unicast+0xf52/0x1260 net/netlink/af_netlink.c:1357
 netlink_sendmsg+0x10da/0x11e0 net/netlink/af_netlink.c:1901
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg+0x30f/0x380 net/socket.c:745
 ____sys_sendmsg+0x877/0xb60 net/socket.c:2597
 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2651
 __sys_sendmsg net/socket.c:2680 [inline]
 __do_sys_sendmsg net/socket.c:2689 [inline]
 __se_sys_sendmsg net/socket.c:2687 [inline]
 __x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2687
 x64_sys_call+0x2dd6/0x3c10 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

Local variable key created at:
 tcf_ct_flow_table_get+0x4a/0x2260 net/sched/act_ct.c:324
 tcf_ct_init+0xa67/0x2890 net/sched/act_ct.c:1408

CPU: 0 PID: 5048 Comm: syz-executor374 Not tainted 6.10.0-syzkaller-11185-g2c9b3512402e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024
=====================================================


---
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 syzkaller@xxxxxxxxxxxxxxxx.

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