rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6160/1:b..l P5208/1:b..l
rcu: (detected by 1, t=10502 jiffies, g=20617, q=629 ncpus=2)
task:udevd state:R running task stack:25504 pid:5208 tgid:5208 ppid:1 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294
irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:unwind_next_frame+0x9b1/0x2550 arch/x86/kernel/unwind_orc.c:-1
Code: 48 89 d8 48 c1 e8 03 80 3c 28 00 74 08 48 89 df e8 84 6b b8 00 48 8b 3b 48 85 ff 0f 84 ee 0d 00 00 48 83 c7 50 e9 3c 01 00 00 <48> 8b 44 24 58 80 3c 28 00 74 11 4c 89 ff e8 5c 6b b8 00 48 8b 74
RSP: 0018:ffffc900025e7218 EFLAGS: 00000246
RAX: ffffc900025e737d RBX: 0000000000000003 RCX: ffffffff904c2e80
RDX: ffffffff90c91fe4 RSI: ffffffff90c91fe8 RDI: ffffffff8c2aa300
RBP: dffffc0000000000 R08: 0000000000000009 R09: ffffffff8e95d060
R10: ffffc900025e7348 R11: fffff520004bce75 R12: ffffffff90c91fe9
R13: 1ffff920004bce69 R14: ffffc900025e7348 R15: ffffc900025e7380
__unwind_start+0x5b8/0x760 arch/x86/kernel/unwind_orc.c:787
unwind_start arch/x86/include/asm/unwind.h:64 [inline]
arch_stack_walk+0xe3/0x150 arch/x86/kernel/stacktrace.c:24
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
save_stack+0x122/0x230 mm/page_owner.c:165
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:320
reset_page_owner include/linux/page_owner.h:25 [inline]
__free_pages_prepare mm/page_alloc.c:1402 [inline]
__free_frozen_pages+0xbc7/0xd30 mm/page_alloc.c:2943
__slab_free+0x274/0x2c0 mm/slub.c:5605
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
kasan_slab_alloc include/linux/kasan.h:253 [inline]
slab_post_alloc_hook mm/slub.c:4569 [inline]
slab_alloc_node mm/slub.c:4898 [inline]
__kmalloc_cache_noprof+0x2ba/0x660 mm/slub.c:5407
kmalloc_noprof include/linux/slab.h:950 [inline]
kzalloc_noprof include/linux/slab.h:1188 [inline]
kernfs_get_open_node fs/kernfs/file.c:543 [inline]
kernfs_fop_open+0x862/0xda0 fs/kernfs/file.c:718
do_dentry_open+0x785/0x14e0 fs/open.c:949
vfs_open+0x3b/0x340 fs/open.c:1081
do_open fs/namei.c:4699 [inline]
path_openat+0x2e08/0x3860 fs/namei.c:4858
do_file_open+0x23e/0x4a0 fs/namei.c:4887
do_sys_openat2+0x113/0x200 fs/open.c:1366
do_sys_open fs/open.c:1372 [inline]
__do_sys_openat fs/open.c:1388 [inline]
__se_sys_openat fs/open.c:1383 [inline]
__x64_sys_openat+0x138/0x170 fs/open.c:1383
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3fe88a7407
RSP: 002b:00007ffee59a5de0 EFLAGS: 00000202 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f3fe8f7a880 RCX: 00007f3fe88a7407
RDX: 0000000000080000 RSI: 00007ffee59a5f60 RDI: ffffffffffffff9c
RBP: 0000000000000008 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000055b629f4f7f5
R13: 000055b629f4f7f5 R14: 0000000000000001 R15: 00007ffee59aa5b0
task:syz-executor state:R running task stack:21968 pid:6160 tgid:6160 ppid:6153 task_flags:0x400100 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7294
irqentry_exit+0x5e4/0x700 kernel/entry/common.c:240
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:debug_lockdep_rcu_enabled+0x0/0x40 kernel/rcu/update.c:319
Code: 48 8d 3d 63 93 7c 04 48 c7 c6 6b 01 0f 8e 67 48 0f b9 3a 90 eb ca cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 31 c0 83 3d 33 38 79 04 00 74 1d 83 3d 0a 6a 79 04 00
RSP: 0018:ffffc90002597d98 EFLAGS: 00000293
RAX: ffffffff818d34a5 RBX: 0000000000000000 RCX: ffff88802d2f8000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90002597ee0 R08: ffffffff818d33d2 R09: ffffffff8e95d060
R10: ffffc90002597e40 R11: fffff520004b2fca R12: ffffffff818d33d2
R13: ffffc90002597e20 R14: 0000000000000000 R15: ffff88802d2f8000
__do_sys_prlimit64 kernel/sys.c:-1 [inline]
__se_sys_prlimit64+0x282/0xbc0 kernel/sys.c:1729
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc20479a3a0
RSP: 002b:00007fff90fde528 EFLAGS: 00000246 ORIG_RAX: 000000000000012e
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007fc20479a3a0
RDX: 0000000000000000 RSI: 0000000000000007 RDI: 0000000000000000
RBP: 00000000000000e1 R08: 0000000000000020 R09: 00007fc2049d3cc0
R10: 00007fff90fde530 R11: 0000000000000246 R12: 00007fff90fde620
R13: 00005555591cbc68 R14: 00005555591cbf1c R15: 00007fff90fde840
rcu: rcu_preempt kthread starved for 10567 jiffies! g20617 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:27968 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5354 [inline]
__schedule+0x165c/0x5520 kernel/sched/core.c:6966
__schedule_loop kernel/sched/core.c:7049 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7064
schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095
rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 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:
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 6532 Comm: vhost-6530 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
RIP: 0010:native_save_fl arch/x86/include/asm/irqflags.h:26 [inline]
RIP: 0010:arch_local_save_flags arch/x86/include/asm/irqflags.h:109 [inline]
RIP: 0010:check_preemption_disabled+0x29/0xe0 lib/smp_processor_id.c:19
Code: 90 55 41 57 41 56 53 65 8b 05 b7 10 87 07 65 8b 0d ac 10 87 07 f7 c1 ff ff ff 7f 74 0c 5b 41 5e 41 5f 5d e9 09 d1 02 00 cc 9c <59> f7 c1 00 02 00 00 74 ea 65 4c 8b 3d 5e 10 87 07 41 f6 47 2f 04
RSP: 0018:ffffc900039e7578 EFLAGS: 00000046
RAX: 0000000000000000 RBX: 00000000ffffffff RCX: 0000000080000000
RDX: 0000000000000000 RSI: ffffffff8e120269 RDI: ffffffff8c2aa360
RBP: 00000000ffffffff R08: ffff88803307bd00 R09: 0000000000000005
R10: 0000000000000004 R11: 0000000000000000 R12: 0000000000000246
R13: ffff88803307bd00 R14: ffff8880312a58f8 R15: 0000000000000000
FS: 00007f4eb7ca86c0(0000) GS:ffff888125206000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000002 CR3: 0000000076110000 CR4: 00000000003526f0
Call Trace:
lockdep_recursion_inc kernel/locking/lockdep.c:465 [inline]
lock_is_held_type+0x5a/0x150 kernel/locking/lockdep.c:5939
lock_is_held include/linux/lockdep.h:249 [inline]
mt_locked lib/maple_tree.c:-1 [inline]
mt_slot lib/maple_tree.c:715 [inline]
mtree_range_walk+0x55e/0x8b0 lib/maple_tree.c:2050
mas_state_walk lib/maple_tree.c:2952 [inline]
mt_find+0x25f/0x630 lib/maple_tree.c:6271
find_vma+0xed/0x160 mm/mmap.c:908
lock_mm_and_find_vma+0x66/0x340 mm/mmap_lock.c:504
do_user_addr_fault+0x330/0x1340 arch/x86/mm/fault.c:1357
handle_page_fault arch/x86/mm/fault.c:1474 [inline]
exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0010:__get_user_2+0x14/0x30 arch/x86/lib/getuser.S:77
Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 ba 00 f0 ff ff ff 7f 00 00 48 39 d0 48 0f 47 c2 0f 01 cb <0f> b7 10 31 c0 0f 01 ca e9 7f 46 04 00 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc900039e7a50 EFLAGS: 00050283
RAX: 0000000000000002 RBX: ffff88804fef01d8 RCX: 0000000000000046
RDX: 00007ffffffff000 RSI: ffffffff8e37de32 RDI: ffffffff8c2aa360
RBP: 0000000000000000 R08: ffffffff8217605f R09: ffff8880312a58f8
R10: dffffc0000000000 R11: fffffbfff206761f R12: dffffc0000000000
R13: ffffc900039e7c00 R14: ffff88804fef0280 R15: ffffc900039e7a58
vhost_get_avail_idx+0xe6/0x460 drivers/vhost/vhost.c:1527
vhost_enable_notify+0x325/0x650 drivers/vhost/vhost.c:3240
vhost_transport_do_send_pkt+0xfb1/0x13a0 drivers/vhost/vsock.c:140
vhost_run_work_list+0x14d/0x1e0 drivers/vhost/vhost.c:454
vhost_task_fn+0x2ef/0x4a0 kernel/vhost_task.c:49
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245