rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4254/1:b..l
(detected by 1, t=10503 jiffies, g=8065, q=34 ncpus=2)
task:syz-executor196 state:R running task stack:25760 pid:4254 ppid:4249 flags:0x00004002
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
irqentry_exit+0x63/0x70 kernel/entry/common.c:439
asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:check_kcov_mode kernel/kcov.c:193 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x32/0x60 kernel/kcov.c:216
Code: 24 98 81 7e 65 8b 15 25 98 81 7e 81 e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 35 83 b9 1c 16 00 00 00 74 2c 8b 91 f8 15 00 00 <83> fa 02 75 21 48 8b 91 00 16 00 00 48 8b 32 48 8d 7e 01 8b 89 fc
RSP: 0018:ffffc90003ce7a60 EFLAGS: 00000246
RAX: ffffffff83c3317c RBX: 0000000000000081 RCX: ffff888018691dc0
RDX: 0000000000000000 RSI: 0000000000000081 RDI: ffff88806e754d00
RBP: 0000000000000000 R08: ffff888018691dc0 R09: 0000000000000002
R10: 000000000000002f R11: 0000000000000000 R12: ffffffff8c3d3b88
R13: dffffc0000000000 R14: ffff88806e754d00 R15: 0000000000000000
security_inode_permission+0xac/0xf0 security/security.c:1340
may_lookup fs/namei.c:1716 [inline]
link_path_walk+0x280/0xe50 fs/namei.c:2267
path_lookupat+0x9d/0x440 fs/namei.c:2478
filename_lookup+0x1f0/0x500 fs/namei.c:2508
user_path_at_empty+0x3e/0x60 fs/namei.c:2905
user_path_at include/linux/namei.h:57 [inline]
ksys_umount fs/namespace.c:1824 [inline]
__do_sys_umount fs/namespace.c:1832 [inline]
__se_sys_umount fs/namespace.c:1830 [inline]
__x64_sys_umount+0xf1/0x160 fs/namespace.c:1830
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5376f33af7
RSP: 002b:00007ffd8c582718 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6
RAX: ffffffffffffffda RBX: 00007f5376f8a0ae RCX: 00007f5376f33af7
RDX: 00007f5376f31617 RSI: 0000000000000002 RDI: 00007f5376f8a1ae
RBP: 00007f5376f8a19e R08: 0000000000000000 R09: 00007ffd8c5828f0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f5376f9033c
R13: 00007f5376f8a106 R14: 0000000000000000 R15: 0000000000000001
</TASK>
rcu: rcu_preempt kthread starved for 10533 jiffies! g8065 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0
rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
rcu: RCU grace-period kthread stack dump:
task:rcu_preempt state:R running task stack:27840 pid:16 ppid:2 flags:0x00004000
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5244 [inline]
__schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
schedule+0xb9/0x180 kernel/sched/core.c:6637
schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
kthread+0x29d/0x330 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
</TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4276 Comm: syz-executor196 Not tainted 6.1.140-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__lock_acquire+0x38c/0x7c50 kernel/locking/lockdep.c:-1
Code: 8d a4 c1 e0 0a 00 00 48 8d 8c c1 00 0b 00 00 48 89 4c 24 18 48 c1 e9 03 48 89 4c 24 50 42 0f b6 04 01 84 c0 0f 85 1f 63 00 00 <4c> 8b 75 18 b8 00 e0 ff ff 41 23 44 24 20 41 81 e7 ff 1f 00 00 44
RSP: 0018:ffffc90003d777c0 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffff88802f68c0d8 RCX: 1ffff1100fb2a160
RDX: 00000000000000a2 RSI: 0000000000000000 RDI: ffff88802f68c0d8
RBP: ffffc90003d77a10 R08: dffffc0000000000 R09: 0000000000000001
R10: fffffbfff1bfd006 R11: 1ffffffff1bfd005 R12: ffff88807d950ae0
R13: 0000000000000000 R14: ffff88807d950ad8 R15: 00000000000000a2
FS: 000055556d1473c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000020000006b000 CR3: 0000000029d40000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
lock_acquire+0x1b4/0x490 kernel/locking/lockdep.c:5662
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
dequeue_signal+0x1cd/0x4b0 kernel/signal.c:705
get_signal+0x547/0x1350 kernel/signal.c:2751
arch_do_signal_or_restart+0xb0/0x1230 arch/x86/kernel/signal.c:871
exit_to_user_mode_loop+0x70/0x110 kernel/entry/common.c:174
exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
__syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
syscall_exit_to_user_mode+0x16/0x40 kernel/entry/common.c:303
do_syscall_64+0x58/0xa0 arch/x86/entry/common.c:87
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f5376f3191a
Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 e3 6a 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 43 6b 02 00 8b 44 24
RSP: 002b:00007ffd8c582540 EFLAGS: 00000293
RAX: fffffffffffffff7 RBX: 0000000000000006 RCX: 00007f5376f3191a
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007f5376ef2990 R09: 00007f5376ef2990
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f5376f9033c
R13: 00007f5376f8a106 R14: 00007ffd8c582590 R15: 0000000000000000
</TASK>
INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.016 msecs