rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P11654/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=79517, q=404 ncpus=2)
task:udevd state:R running task stack:24600 pid:11654 tgid:11654 ppid:4978 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7189
preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline]
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline]
irqentry_exit+0x1fe/0x790 kernel/entry/common.c:164
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:lock_acquire+0x5e/0x370 kernel/locking/lockdep.c:5872
Code: 05 bb 3d 26 12 83 f8 07 0f 87 d9 02 00 00 48 0f a3 05 c6 29 f3 0e 0f 82 a4 02 00 00 8b 35 4e 5d f3 0e 85 f6 0f 85 bf 00 00 00 <48> 8b 44 24 30 65 48 2b 05 5d 3d 26 12 0f 85 ed 02 00 00 48 83 c4
RSP: 0018:ffffc900038d77e8 EFLAGS: 00000206
RAX: 0000000000000046 RBX: 0000000000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffffff8defaa14 RDI: ffffffff8c1c3680
RBP: ffffffff8e7e54e0 R08: 0000000064a9034e R09: 0000000000000007
R10: 0000000000000200 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
rcu_read_lock include/linux/rcupdate.h:838 [inline]
class_rcu_constructor include/linux/rcupdate.h:1181 [inline]
kernfs_root+0x34/0x2a0 fs/kernfs/kernfs-internal.h:74
kernfs_root_is_locked fs/kernfs/kernfs-internal.h:108 [inline]
kernfs_parent fs/kernfs/kernfs-internal.h:132 [inline]
kernfs_get_target_path fs/kernfs/symlink.c:68 [inline]
kernfs_getlink fs/kernfs/symlink.c:122 [inline]
kernfs_iop_get_link fs/kernfs/symlink.c:140 [inline]
kernfs_iop_get_link+0x3c8/0x16a0 fs/kernfs/symlink.c:128
pick_link+0xd17/0x13c0 fs/namei.c:2064
step_into_slowpath+0x9ba/0xf90 fs/namei.c:2123
step_into fs/namei.c:2148 [inline]
open_last_lookups fs/namei.c:4646 [inline]
path_openat+0xf95/0x31a0 fs/namei.c:4855
do_file_open+0x20e/0x430 fs/namei.c:4887
do_sys_openat2+0x10d/0x1e0 fs/open.c:1364
do_sys_open fs/open.c:1370 [inline]
__do_sys_openat fs/open.c:1386 [inline]
__se_sys_openat fs/open.c:1381 [inline]
__x64_sys_openat+0x12d/0x210 fs/open.c:1381
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fd30f6a7407
RSP: 002b:00007fff4ca00920 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007fd30feb5880 RCX: 00007fd30f6a7407
RDX: 0000000000080000 RSI: 0000555dd51331e0 RDI: ffffffffffffff9c
RBP: 0000555dd51331e0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000009
rcu: rcu_preempt kthread starved for 10471 jiffies! g79517 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:28216 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x10e9/0x6820 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7283
schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297
kthread+0x370/0x450 kernel/kthread.c:436
ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: Stack dump where RCU GP kthread last ran:
CPU: 0 UID: 0 PID: 12493 Comm: syz.4.1787 Tainted: G L syzkaller #0 PREEMPT(full)
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0x589/0x1700 kernel/smp.c:892
Code: b8 00 00 00 00 00 fc ff df 48 8b 54 24 08 49 89 d5 49 89 d4 49 c1 ed 03 41 83 e4 07 49 01 c5 41 83 c4 03 e8 79 83 0c 00 f3 90 <41> 0f b6 45 00 41 38 c4 7c 08 84 c0 0f 85 63 0f 00 00 8b 45 08 31
RSP: 0018:ffffc9000204f268 EFLAGS: 00000246
RAX: 0000000000080000 RBX: 0000000000000001 RCX: ffffc9000e6f3000
RDX: 0000000000080000 RSI: ffffffff81fc0fa7 RDI: ffff88801e7f0000
RBP: ffff8880b8540f40 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000003
R13: ffffed10170a81e9 R14: 0000000000000001 R15: ffff8880b843c5c0
FS: 00007f1c42a6a6c0(0000) GS:ffff888124375000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000b36030 CR3: 000000003bdee000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1057
__flush_tlb_multi arch/x86/include/asm/paravirt.h:46 [inline]
flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline]
flush_tlb_mm_range+0x45f/0x16f0 arch/x86/mm/tlb.c:1451
flush_tlb_page arch/x86/include/asm/tlbflush.h:345 [inline]
ptep_clear_flush+0x148/0x170 mm/pgtable-generic.c:104
wp_page_copy mm/memory.c:3925 [inline]
do_wp_page+0x12a4/0x4350 mm/memory.c:4320
handle_pte_fault mm/memory.c:6427 [inline]
__handle_mm_fault+0x1ab6/0x2a00 mm/memory.c:6549
handle_mm_fault+0x36d/0xa20 mm/memory.c:6718
do_user_addr_fault+0x74c/0x12f0 arch/x86/mm/fault.c:1385
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__put_user_nocheck_4+0x3/0x10 arch/x86/lib/putuser.S:104
Code: d9 0f 01 cb 89 01 31 c9 0f 01 ca e9 c7 d7 03 00 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 01 cb <89> 01 31 c9 0f 01 ca c3 cc cc cc cc 90 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc9000204f9d8 EFLAGS: 00050246
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000200000b36030
RDX: 0000000000080000 RSI: ffffffff895585c1 RDI: ffff88801e7f0000
RBP: ffffc9000204fd78 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000000 R12: 0000000000000000
R13: 0000200000b36000 R14: ffffc9000204fdbc R15: 0000000000000002
____sys_recvmsg+0x2ec/0x640 net/socket.c:2931
___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960
do_recvmmsg+0x301/0x760 net/socket.c:3055
__sys_recvmmsg net/socket.c:3129 [inline]
__do_sys_recvmmsg net/socket.c:3152 [inline]
__se_sys_recvmmsg net/socket.c:3145 [inline]
__x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1c41b9cdd9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1c42a6a028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b
RAX: ffffffffffffffda RBX: 00007f1c41e16090 RCX: 00007f1c41b9cdd9
RDX: 00000000080002c1 RSI: 0000200000000040 RDI: 0000000000000007
RBP: 00007f1c41c32d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1c41e16128 R14: 00007f1c41e16090 R15: 00007ffcd2bd0f08