rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 0-...!: (1 GPs behind) idle=36ec/1/0x4000000000000000 softirq=51682/51683 fqs=0
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P10988/1:b..l P5843/1:b..l
rcu: (detected by 1, t=10505 jiffies, g=38721, q=343 ncpus=2)
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 8022 Comm: udevd Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:lookup_chain_cache kernel/locking/lockdep.c:3804 [inline]
RIP: 0010:lookup_chain_cache_add kernel/locking/lockdep.c:3824 [inline]
RIP: 0010:validate_chain+0xa4/0x2140 kernel/locking/lockdep.c:3879
Code: c6 47 5f a6 8d e8 dc 94 e5 ff 90 0f 0b 90 90 90 48 bb eb 83 b5 80 46 86 c8 61 49 0f af df 48 c1 eb 2d 48 8b 04 dd 20 43 60 93 <48> 85 c0 0f 94 c1 48 83 c0 f8 0f 94 c2 08 ca 0f 84 24 01 00 00 e8
RSP: 0018:ffffc90000007a18 EFLAGS: 00000806
RAX: ffffffff93ba1578 RBX: 00000000000639d1 RCX: 0000000000040000
RDX: 0000000000000001 RSI: ffff8880255aa918 RDI: ffff8880255a9e00
RBP: 0000000000000001 R08: 0000000000000000 R09: ffffffff89863f04
R10: dffffc0000000000 R11: ffffffff89863e40 R12: 0000000000000001
R13: ffff8880255aa8f0 R14: ffff8880255aa918 R15: 8c22c8e7a06d7a59
FS: 00007f020cfdb880(0000) GS:ffff888125c57000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555573cca808 CR3: 000000007d5c8000 CR4: 00000000003526f0
Call Trace:
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5240
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5871
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
advance_sched+0xc4/0xc90 net/sched/sch_taprio.c:924
__run_hrtimer kernel/time/hrtimer.c:1761 [inline]
__hrtimer_run_queues+0x529/0xc60 kernel/time/hrtimer.c:1825
hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline]
__sysvec_apic_timer_interrupt+0x108/0x410 arch/x86/kernel/apic/apic.c:1056
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5875
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 7b 55 fe 10 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9000bcdf7b8 EFLAGS: 00000206
RAX: 6d67042a964bd000 RBX: 0000000000000000 RCX: 6d67042a964bd000
RDX: 0000000000000001 RSI: ffffffff8db6f792 RDI: ffffffff8be1b9c0
RBP: ffffffff8172aae5 R08: 0000000000000000 R09: ffffffff8172aae5
R10: ffffc9000bcdf978 R11: ffffffff81acfd30 R12: 0000000000000002
R13: ffffffff8e13f0e0 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
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:247 [inline]
__kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2381 [inline]
slab_free mm/slub.c:4643 [inline]
kmem_cache_free+0x18f/0x400 mm/slub.c:4745
vfs_fstatat+0x122/0x170 fs/stat.c:376
__do_sys_newfstatat fs/stat.c:542 [inline]
__se_sys_newfstatat fs/stat.c:536 [inline]
__x64_sys_newfstatat+0x116/0x190 fs/stat.c:536
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: 0033:0x7f020c911b0a
Code: 48 8b 15 f1 f2 0d 00 f7 d8 64 89 02 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 41 89 ca b8 06 01 00 00 0f 05 <3d> 00 f0 ff ff 77 07 31 c0 c3 0f 1f 40 00 48 8b 15 b9 f2 0d 00 f7
RSP: 002b:00007ffd5ff7a2c8 EFLAGS: 00000202 ORIG_RAX: 0000000000000106
RAX: ffffffffffffffda RBX: 00007ffd5ff7aca0 RCX: 00007f020c911b0a
RDX: 00007ffd5ff7a2f0 RSI: 00007ffd5ff7aca0 RDI: 00000000ffffff9c
RBP: 00007ffd5ff7acaf R08: 0000000000000075 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000202 R12: 0000556d64de7d65
R13: 00007ffd5ff7a380 R14: 0000556d610556d7 R15: 0000556d64de7d60
task:syz-executor state:R running task stack:21840 pid:5843 tgid:5843 ppid:5826 task_flags:0x400140 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
preempt_schedule_common+0x83/0xd0 kernel/sched/core.c:6966
preempt_schedule+0xae/0xc0 kernel/sched/core.c:6990
preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12
__raw_spin_unlock include/linux/spinlock_api_smp.h:143 [inline]
_raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186
spin_unlock include/linux/spinlock.h:391 [inline]
copy_pte_range mm/memory.c:1206 [inline]
copy_pmd_range+0x6727/0x7000 mm/memory.c:1267
copy_pud_range mm/memory.c:1304 [inline]
copy_p4d_range mm/memory.c:1328 [inline]
copy_page_range+0xc46/0x1270 mm/memory.c:1416
dup_mmap+0xf57/0x1ac0 mm/mmap.c:1838
dup_mm kernel/fork.c:1477 [inline]
copy_mm+0x13c/0x4b0 kernel/fork.c:1529
copy_process+0x16d3/0x3b80 kernel/fork.c:2169
kernel_clone+0x224/0x7f0 kernel/fork.c:2599
__do_sys_clone kernel/fork.c:2742 [inline]
__se_sys_clone kernel/fork.c:2726 [inline]
__x64_sys_clone+0x18b/0x1e0 kernel/fork.c:2726
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: 0033:0x7feb78385213
RSP: 002b:00007fff402a06a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007feb78385213
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 000055556f2797d0 R11: 0000000000000246 R12: 0000000000000000
R13: 00000000000927c0 R14: 00000000000a673e R15: 00007fff402a0840
task:syz.3.1287 state:R running task stack:22344 pid:10988 tgid:10988 ppid:5837 task_flags:0x400640 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7109
irqentry_exit+0x6f/0x90 kernel/entry/common.c:307
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:707
RIP: 0010:preempt_count kernel/rcu/tree.c:3991 [inline]
RIP: 0010:rcu_lockdep_current_cpu_online+0x8/0x120 kernel/rcu/tree.c:3995
Code: df e9 4e ff ff ff 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 57 41 56 <53> 65 8b 0d e0 1e f5 10 b0 01 f7 c1 00 00 f0 00 0f 85 d5 00 00 00
RSP: 0018:ffffc9001a866cc8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000000000000 RCX: 19dc6fea93f89300
RDX: ffff88802bc80000 RSI: ffffffff8be1b9a0 RDI: ffffffff8be1b960
RBP: ffffc9001a866db8 R08: 0000000000000000 R09: ffffffff81f5fa5d
R10: ffffc9001a866dc0 R11: fffff5200350cdbb R12: 0000000000000000
R13: dffffc0000000000 R14: ffff888056436c02 R15: 0000000000000156
rcu_read_lock_held_common kernel/rcu/update.c:113 [inline]
rcu_read_lock_held+0x1e/0x50 kernel/rcu/update.c:349
xa_entry include/linux/xarray.h:1226 [inline]
xas_descend lib/xarray.c:208 [inline]
xas_load+0x1df/0x5b0 lib/xarray.c:246
filemap_get_entry+0x168/0x2f0 mm/filemap.c:1870
shmem_get_folio_gfp+0x237/0x1660 mm/shmem.c:2460
shmem_get_folio mm/shmem.c:2642 [inline]
shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3292
generic_perform_write+0x2c7/0x910 mm/filemap.c:4112
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3467
__kernel_write_iter+0x390/0x860 fs/read_write.c:619
dump_emit_page fs/coredump.c:1112 [inline]
dump_user_range+0x873/0xc70 fs/coredump.c:1186
elf_core_dump+0x32ed/0x3900 fs/binfmt_elf.c:2075
do_coredump+0x2806/0x3440 fs/coredump.c:950
get_signal+0x10d9/0x1310 kernel/signal.c:3019
arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
irqentry_exit_to_user_mode+0x81/0x120 kernel/entry/common.c:184
exc_page_fault+0x9f/0xf0 arch/x86/mm/fault.c:1535
asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
RIP: 0033:0x7f4b8764f837
RSP: 002b:00007f4b88633120 EFLAGS: 00010202
RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f4b8778e9a9
RDX: 00007f4b88633140 RSI: 00007f4b88633270 RDI: 000000000000000b
RBP: 00007f4b87810d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f4b879b6240 R15: 00007fffdf195518
rcu: rcu_preempt kthread starved for 10505 jiffies! g38721 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:27320 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x16aa/0x4c90 kernel/sched/core.c:6786
__schedule_loop kernel/sched/core.c:6864 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6879
schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99
rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054
rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/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:
CPU: 1 UID: 0 PID: 7024 Comm: kworker/u8:25 Not tainted 6.16.0-rc7-syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline]
RIP: 0010:smp_call_function_many_cond+0xf69/0x12d0 kernel/smp.c:885
Code: 00 45 8b 2f 44 89 ee 83 e6 01 31 ff e8 80 6e 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 2b 6a 0b 00 eb 37 f3 90 <43> 0f b6 04 2c 84 c0 75 10 41 f7 07 01 00 00 00 74 1e e8 10 6a 0b
RSP: 0018:ffffc9000f5e76a0 EFLAGS: 00000293
RAX: ffffffff81b4bba0 RBX: ffff8880b873b040 RCX: ffff88802a303c00
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc9000f5e7800 R08: ffffffff8fa0b2f7 R09: 1ffffffff1f4165e
R10: dffffc0000000000 R11: fffffbfff1f4165f R12: 1ffff110170c835d
R13: dffffc0000000000 R14: 0000000000000000 R15: ffff8880b8641ae8
FS: 0000000000000000(0000) GS:ffff888125d57000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa19dc9ef98 CR3: 000000000df38000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1052
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2691 [inline]
smp_text_poke_batch_finish+0x5e0/0x1100 arch/x86/kernel/alternative.c:2901
arch_jump_label_transform_apply+0x1c/0x30 arch/x86/kernel/jump_label.c:146
static_key_enable_cpuslocked+0x128/0x250 kernel/jump_label.c:210
static_key_enable+0x1a/0x20 kernel/jump_label.c:223
toggle_allocation_gate+0xad/0x240 mm/kfence/core.c:850
process_one_work kernel/workqueue.c:3238 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3321
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3402
kthread+0x711/0x8a0 kernel/kthread.c:464
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245