rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P19700/1:b..l P5137/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=203317, q=192 ncpus=2)
task:udevd state:R running task stack:23048 pid:5137 ppid:1 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
irqentry_exit+0x67/0x70 kernel/entry/common.c:438
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:lock_acquire+0x208/0x420 kernel/locking/lockdep.c:5758
Code: f7 84 24 80 00 00 00 00 02 00 00 43 c6 44 3c 04 f8 0f 85 f0 00 00 00 41 f7 c6 00 02 00 00 74 01 fb 48 c7 44 24 60 0e 36 e0 45 <4b> c7 04 3c 00 00 00 00 43 c7 44 3c 08 00 00 00 00 65 48 8b 04 25
RSP: 0018:ffffc90003297820 EFLAGS: 00000206
RAX: 0000000000000001 RBX: 0000000000000000 RCX: fedfd28e6f9a5600
RDX: 0000000000000000 RSI: ffffffff8acadae0 RDI: ffffffff8b1c85a0
RBP: ffffc90003297930 R08: dffffc0000000000 R09: 1ffffffff22382a0
R10: dffffc0000000000 R11: fffffbfff22382a1 R12: 1ffff92000652f10
R13: ffffffff8d132060 R14: 0000000000000246 R15: dffffc0000000000
rcu_lock_acquire include/linux/rcupdate.h:334 [inline]
rcu_read_lock include/linux/rcupdate.h:786 [inline]
__d_lookup+0xac/0x7c0 fs/dcache.c:2489
lookup_fast+0x7c/0x4d0 fs/namei.c:1660
walk_component fs/namei.c:2006 [inline]
link_path_walk+0x5ff/0xe30 fs/namei.c:2337
path_lookupat+0x9d/0x440 fs/namei.c:2490
filename_lookup+0x228/0x560 fs/namei.c:2520
user_path_at_empty+0x42/0x60 fs/namei.c:2917
do_readlinkat+0xdd/0x490 fs/stat.c:494
__do_sys_readlink fs/stat.c:527 [inline]
__se_sys_readlink fs/stat.c:524 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:524
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f29065153a7
RSP: 002b:00007ffdde038cc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffdde0391a0 RCX: 00007f29065153a7
RDX: 0000000000000400 RSI: 00007ffdde038cd0 RDI: 00007ffdde0391a0
RBP: 00007ffdde038cd0 R08: 0000555683ac8e04 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 00000000000000ff R14: 0000555662034be0 R15: 00007ffdde039c60
task:syz-executor state:R running task stack:21704 pid:19700 ppid:19689 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
preempt_schedule_common+0x82/0xc0 kernel/sched/core.c:6867
preempt_schedule+0xc0/0xd0 kernel/sched/core.c:6891
preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3a/0x40 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1107 [inline]
copy_pmd_range mm/memory.c:1168 [inline]
copy_pud_range mm/memory.c:1205 [inline]
copy_p4d_range mm/memory.c:1229 [inline]
copy_page_range+0x2ba0/0x3670 mm/memory.c:1323
dup_mmap kernel/fork.c:764 [inline]
dup_mm kernel/fork.c:1692 [inline]
copy_mm+0x11cb/0x1d50 kernel/fork.c:1741
copy_process+0x16f7/0x3d80 kernel/fork.c:2506
kernel_clone+0x24b/0x8a0 kernel/fork.c:2914
__do_sys_clone kernel/fork.c:3057 [inline]
__se_sys_clone kernel/fork.c:3041 [inline]
__x64_sys_clone+0x1b7/0x230 kernel/fork.c:3041
do_syscall_x64 arch/x86/entry/common.c:46 [inline]
do_syscall_64+0x55/0xa0 arch/x86/entry/common.c:76
entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fc8d11c5212
RSP: 002b:00007fffd2fe8f70 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 00007fffd2fe8f70 RCX: 00007fc8d11c5212
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 00007fffd2fe90fc R08: 0000000000000000 R09: 0000000000000001
R10: 0000555581ec27d0 R11: 0000000000000246 R12: 0000000000000001
R13: 00000000000927c0 R14: 00000000001c2dea R15: 00007fffd2fe9150
rcu: rcu_preempt kthread starved for 10445 jiffies! g203317 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27344 pid:17 ppid:2 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5381 [inline]
__schedule+0x1553/0x45a0 kernel/sched/core.c:6700
schedule+0xbd/0x170 kernel/sched/core.c:6774
schedule_timeout+0x188/0x2d0 kernel/time/timer.c:2168
rcu_gp_fqs_loop+0x313/0x1590 kernel/rcu/tree.c:1667
rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
kthread+0x2fa/0x390 kernel/kthread.c:388
ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
rcu: Stack dump where RCU GP kthread last ran:
CPU: 1 PID: 0 Comm: swapper/1 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:pv_native_safe_halt+0xf/0x10 arch/x86/kernel/paravirt.c:148
Code: 40 22 02 c3 cc cc cc cc cc cc cc f3 0f 1e fa 0f 0b 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 66 90 0f 00 2d c3 29 43 00 fb f4 66 0f 1f 00 55 41 57 41 56 41 54 53 50 8b 2f eb 2e 41 89 de 80
RSP: 0018:ffffc90000187de0 EFLAGS: 000002c6
RAX: 30f799da78cc2200 RBX: ffffffff8162ac40 RCX: 30f799da78cc2200
RDX: 0000000000000001 RSI: ffffffff8acac960 RDI: ffffffff8b1c85a0
RBP: ffffc90000187f20 R08: ffff8880b8f36b2b R09: 1ffff110171e6d65
R10: dffffc0000000000 R11: ffffed10171e6d66 R12: 1ffff110036cd780
R13: 1ffff92000030fc8 R14: 0000000000000001 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555925884e8 CR3: 0000000025f0a000 CR4: 00000000003506e0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:108 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:753
default_idle_call+0x6c/0xa0 kernel/sched/idle.c:97
cpuidle_idle_call kernel/sched/idle.c:170 [inline]
do_idle+0x1f0/0x4e0 kernel/sched/idle.c:282
cpu_startup_entry+0x43/0x60 kernel/sched/idle.c:380
start_secondary+0xee/0xf0 arch/x86/kernel/smpboot.c:323
secondary_startup_64_no_verify+0x179/0x17b