rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5224/1:b..l P3523/1:b..l P6939/1:b..l P6934/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=21637, q=960845 ncpus=2)
task:syz-executor state:R running task stack:21544 pid:6934 tgid:6934 ppid:1 task_flags:0x40054c flags:0x20004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:debug_lockdep_rcu_enabled+0x2a/0x40 kernel/rcu/update.c:321
Code: f3 0f 1e fa 31 c0 83 3d 57 d8 29 04 00 74 1e 83 3d 6a 08 2a 04 00 74 15 65 48 8b 0c 25 08 50 a0 92 31 c0 83 b9 ec 0a 00 00 00 <0f> 94 c0 e9 0e dc 02 00 cc cc cc cc cc cc cc cc cc cc cc cc cc cc
RSP: 0018:ffffc9000bd87530 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff90db6c01 RCX: ffff8880258c0000
RDX: ffffc9000bd87601 RSI: dffffc0000000000 RDI: ffffc9000bd87610
RBP: dffffc0000000000 R08: ffffc9000bd87f30 R09: 0000000000000000
R10: ffffc9000bd87658 R11: fffff520017b0ecd R12: ffffc9000bd87f40
R13: ffffc9000bd80000 R14: ffffc9000bd87608 R15: ffffffff8172c195
rcu_read_unlock include/linux/rcupdate.h:869 [inline]
class_rcu_destructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0x195c/0x2390 arch/x86/kernel/unwind_orc.c:680
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
vfree+0x25a/0x400 mm/vmalloc.c:3434
kcov_put kernel/kcov.c:439 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:535
__fput+0x449/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6b5/0x2300 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
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_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fa6539
RSP: 002b:00000000f758f930 EFLAGS: 00000206 ORIG_RAX: 0000000000000004
RAX: 0000000000000001 RBX: 0000000000000003 RCX: 00000000f758f970
RDX: 0000000000000001 RSI: 00000000f7434ff4 RDI: 0000000000000000
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
task:syz-executor state:R running task stack:21512 pid:6939 tgid:6939 ppid:1 task_flags:0x40054c flags:0x20004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 4b f4 02 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000bd07498 EFLAGS: 00000206
RAX: 486077e9b4eee600 RBX: 0000000000000000 RCX: 486077e9b4eee600
RDX: 0000000000000001 RSI: ffffffff8dba6738 RDI: ffffffff8be33680
RBP: ffffffff8172c195 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc9000bd07658 R11: ffffffff81ac3810 R12: 0000000000000002
R13: ffffffff8e139ee0 R14: 0000000000000000 R15: 0000000000000246
rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
rcu_read_lock include/linux/rcupdate.h:841 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xc2/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
vfree+0x25a/0x400 mm/vmalloc.c:3434
kcov_put kernel/kcov.c:439 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:535
__fput+0x449/0xa70 fs/file_table.c:468
task_work_run+0x1d4/0x260 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x6b5/0x2300 kernel/exit.c:961
do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
get_signal+0x1286/0x1340 kernel/signal.c:3034
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
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_fast_syscall_32+0x1f4/0x2b0 arch/x86/entry/syscall_32.c:309
do_fast_syscall_32+0x34/0x80 arch/x86/entry/syscall_32.c:331
entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7f21539
RSP: 002b:00000000f750fd78 EFLAGS: 00000206 ORIG_RAX: 0000000000000128
RAX: 0000000000000000 RBX: 00000000ffffff9c RCX: 00000000f750fe14
RDX: 00000000000001ff RSI: 00000000f7236de0 RDI: 0000000000000001
RBP: 00000000f7238230 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
task:kworker/u8:9 state:R running task stack:24104 pid:3523 tgid:3523 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: kvfree_rcu_reclaim kfree_rcu_monitor
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:debug_lockdep_rcu_enabled+0x16/0x40 kernel/rcu/update.c:320
Code: cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 31 c0 83 3d 57 d8 29 04 00 74 1e 83 3d 6a 08 2a 04 00 <74> 15 65 48 8b 0c 25 08 50 a0 92 31 c0 83 b9 ec 0a 00 00 00 0f 94
RSP: 0018:ffffc9000c217470 EFLAGS: 00000202
RAX: 0000000000000000 RBX: ffffffff820497f1 RCX: 9a360c6231645d00
RDX: 0000000000000000 RSI: ffffffff8dba6738 RDI: ffffffff8be33680
RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffffff8172c195
R10: ffffc9000c217598 R11: ffffffff81ac3810 R12: 1ffff92001842ea9
R13: ffffc9000c217580 R14: ffffc9000c217548 R15: ffffffff8172c195
rcu_read_lock include/linux/rcupdate.h:842 [inline]
class_rcu_constructor include/linux/rcupdate.h:1155 [inline]
unwind_next_frame+0xcb/0x2390 arch/x86/kernel/unwind_orc.c:479
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
poison_slab_object mm/kasan/common.c:243 [inline]
__kasan_slab_free+0x5b/0x80 mm/kasan/common.c:275
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2417 [inline]
slab_free_freelist_hook mm/slub.c:2446 [inline]
slab_free_bulk mm/slub.c:4704 [inline]
kmem_cache_free_bulk+0x2d1/0x520 mm/slub.c:5283
kfree_bulk include/linux/slab.h:794 [inline]
kvfree_rcu_bulk+0xe5/0x1f0 mm/slab_common.c:1516
kvfree_rcu_drain_ready mm/slab_common.c:1699 [inline]
kfree_rcu_monitor+0x211/0x2a0 mm/slab_common.c:1772
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xae1/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
task:klogd state:R running task stack:24104 pid:5224 tgid:5224 ppid:1 task_flags:0x400100 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7288
irqentry_exit+0x6f/0x90 kernel/entry/common.c:197
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:__orc_find arch/x86/kernel/unwind_orc.c:109 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x2b4/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: 00 00 fc ff df 0f 84 03 02 00 00 4a 8d 14 ad b4 7e b1 8f 45 29 e8 4a 8d 1c 82 48 83 c3 fc 49 89 d5 48 39 da 0f 86 1c 10 00 00 <49> 29 d5 e9 80 00 00 00 31 db e9 eb 16 00 00 49 81 fc 00 10 0a 91
RSP: 0018:ffffc90002fe71b8 EFLAGS: 00000202
RAX: ffffffff8fbf71d4 RBX: ffffffff8fbf71d8 RCX: ffffffff8fbf71dc
RDX: ffffffff8fbf71d8 RSI: ffffffff903f724a RDI: ffffffff8be33620
RBP: ffffffff8fbf71dc R08: 0000000000000001 R09: ffffffff8172c195
R10: ffffc90002fe72d8 R11: ffffffff81ac3810 R12: ffffffff82157783
R13: ffffffff8fbf71d8 R14: ffffc90002fe7288 R15: ffffffff8fbf71d8
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf5/0x1f0 mm/page_owner.c:156
__reset_page_owner+0x71/0x1f0 mm/page_owner.c:308
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1395 [inline]
__free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
discard_slab mm/slub.c:2753 [inline]
__put_partials+0x156/0x1a0 mm/slub.c:3218
put_cpu_partial+0x17c/0x250 mm/slub.c:3293
__slab_free+0x2d5/0x3c0 mm/slub.c:4550
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x97/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
__kasan_kmalloc+0x22/0xb0 mm/kasan/common.c:396
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4365 [inline]
__kmalloc_node_track_caller_noprof+0x271/0x4e0 mm/slub.c:4384
kmalloc_reserve+0x136/0x290 net/core/skbuff.c:600
__alloc_skb+0x142/0x2d0 net/core/skbuff.c:669
alloc_skb include/linux/skbuff.h:1336 [inline]
alloc_skb_with_frags+0xca/0x890 net/core/skbuff.c:6665
sock_alloc_send_pskb+0x857/0x990 net/core/sock.c:2980
unix_dgram_sendmsg+0x461/0x1850 net/unix/af_unix.c:2153
sock_sendmsg_nosec net/socket.c:714 [inline]
__sock_sendmsg+0x21c/0x270 net/socket.c:729
__sys_sendto+0x3bd/0x520 net/socket.c:2228
__do_sys_sendto net/socket.c:2235 [inline]
__se_sys_sendto net/socket.c:2231 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2231
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f243eaa8407
RSP: 002b:00007ffc02f22cf0 EFLAGS: 00000202 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f243e958c80 RCX: 00007f243eaa8407
RDX: 0000000000000055 RSI: 00007ffc02f22e30 RDI: 0000000000000003
RBP: 00007ffc02f23260 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000004000 R11: 0000000000000202 R12: 00007ffc02f23278
R13: 00007ffc02f22e30 R14: 000000000000003a R15: 00007ffc02f22e30
rcu: rcu_preempt kthread starved for 10480 jiffies! g21637 f0x2 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:27224 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
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 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82
Code: 53 e7 02 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d f3 86 0e 00 f3 0f 1e fa fb f4 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000197de0 EFLAGS: 000002c2
RAX: 75275b70339f1000 RBX: ffffffff819683b8 RCX: 75275b70339f1000
RDX: 0000000000000001 RSI: ffffffff8d9b7339 RDI: ffffffff8be33680
RBP: ffffc90000197f20 R08: ffff8880b8732f9b R09: 1ffff110170e65f3
R10: dffffc0000000000 R11: ffffed10170e65f4 R12: ffffffff8fa38630
R13: 0000000000000001 R14: 0000000000000001 R15: 1ffff110039d7b40
FS: 0000000000000000(0000) GS:ffff888125d1b000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000f51fd2b3 CR3: 000000004fd96000 CR4: 00000000003526f0
Call Trace:
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:757
default_idle_call+0x74/0xb0 kernel/sched/idle.c:122
cpuidle_idle_call kernel/sched/idle.c:190 [inline]
do_idle+0x1e8/0x510 kernel/sched/idle.c:330
cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:428
start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x147