[syzbot] [kernel?] KMSAN: uninit-value in psi_task_change

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 9b0d551bcc05 Merge tag 'pull-misc' of git://git.kernel.org..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1539392f980000
kernel config: https://syzkaller.appspot.com/x/.config?x=50fb29d81ff5a3df
dashboard link: https://syzkaller.appspot.com/bug?extid=6a41c3d25697203c245a
compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/90b0fb888152/disk-9b0d551b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/1120c646f284/vmlinux-9b0d551b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/df9bbfa8cbe6/bzImage-9b0d551b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+6a41c3...@syzkaller.appspotmail.com

=====================================================
BUG: KMSAN: uninit-value in kernfs_ino include/linux/kernfs.h:368 [inline]
BUG: KMSAN: uninit-value in cgroup_ino include/linux/cgroup.h:590 [inline]
BUG: KMSAN: uninit-value in cgroup_psi include/linux/psi.h:37 [inline]
BUG: KMSAN: uninit-value in task_psi_group kernel/sched/psi.c:889 [inline]
BUG: KMSAN: uninit-value in psi_task_change+0x4ba/0x710 kernel/sched/psi.c:921
kernfs_ino include/linux/kernfs.h:368 [inline]
cgroup_ino include/linux/cgroup.h:590 [inline]
cgroup_psi include/linux/psi.h:37 [inline]
task_psi_group kernel/sched/psi.c:889 [inline]
psi_task_change+0x4ba/0x710 kernel/sched/psi.c:921
psi_enqueue kernel/sched/stats.h:166 [inline]
enqueue_task+0x32d/0x390 kernel/sched/core.c:2094
activate_task kernel/sched/core.c:2134 [inline]
ttwu_do_activate+0x1dd/0x9d0 kernel/sched/core.c:3706
ttwu_queue kernel/sched/core.c:3969 [inline]
try_to_wake_up+0xf83/0x1f50 kernel/sched/core.c:4293
wake_up_process+0x2a/0x40 kernel/sched/core.c:4424
hrtimer_wakeup+0x85/0xd0 kernel/time/hrtimer.c:2013
__run_hrtimer kernel/time/hrtimer.c:1777 [inline]
__hrtimer_run_queues+0x559/0xd80 kernel/time/hrtimer.c:1841
hrtimer_interrupt+0x456/0xb80 kernel/time/hrtimer.c:1903
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1041 [inline]
__sysvec_apic_timer_interrupt+0xa7/0x420 arch/x86/kernel/apic/apic.c:1058
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1052 [inline]
sysvec_apic_timer_interrupt+0x7f/0x90 arch/x86/kernel/apic/apic.c:1052
asm_sysvec_apic_timer_interrupt+0x1f/0x30 arch/x86/include/asm/idtentry.h:702
finish_task_switch+0x184/0x920 kernel/sched/core.c:5193
context_switch kernel/sched/core.c:5328 [inline]
__schedule+0x2331/0x7790 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x17d/0x3c0 kernel/sched/core.c:7026
exit_to_user_mode_loop+0x6c/0x370 kernel/entry/common.c:31
exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
do_syscall_64+0x1e3/0x210 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
__netns_tracker_alloc include/net/net_namespace.h:362 [inline]
sk_alloc+0x5de/0x8a0 net/core/sock.c:2311
__netlink_create net/netlink/af_netlink.c:628 [inline]
__netlink_kernel_create+0x19b/0xcc0 net/netlink/af_netlink.c:2020
netlink_kernel_create include/linux/netlink.h:62 [inline]
rtnetlink_net_init+0x6b/0x110 net/core/rtnetlink.c:7038
ops_init+0x2b3/0x9f0 net/core/net_namespace.c:137
__register_pernet_operations net/core/net_namespace.c:1314 [inline]
register_pernet_operations+0x649/0xfa0 net/core/net_namespace.c:1391
register_pernet_subsys+0x5b/0xa0 net/core/net_namespace.c:1432
rtnetlink_init+0x29/0xa0 net/core/rtnetlink.c:7093
netlink_proto_init+0x1f8/0x280 net/netlink/af_netlink.c:2948
do_one_initcall+0x237/0xb60 init/main.c:1283
do_initcall_level+0x157/0x2e0 init/main.c:1345
do_initcalls+0x176/0x310 init/main.c:1361
do_basic_setup+0x1d/0x30 init/main.c:1380
kernel_init_freeable+0x275/0x4a0 init/main.c:1593
kernel_init+0x2f/0x5e0 init/main.c:1483
ret_from_fork+0x233/0x380 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

CPU: 0 UID: 0 PID: 31572 Comm: syz.3.9106 Tainted: G W syzkaller #0 PREEMPT(none)
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
=====================================================


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