rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 1-...!: (1 GPs behind) idle=fa6c/1/0x4000000000000000 softirq=49303/49304 fqs=3
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5633/1:b..l
rcu: (detected by 0, t=10506 jiffies, g=45189, q=1118 ncpus=2)
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 10519 Comm: syz.8.1408 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:get_current arch/x86/include/asm/current.h:25 [inline]
RIP: 0010:write_comp_data kernel/kcov.c:245 [inline]
RIP: 0010:__sanitizer_cov_trace_cmp8+0x8/0x90 kernel/kcov.c:294
Code: 89 44 11 20 e9 c4 88 4a ff cc 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 48 8b 04 24 <65> 48 8b 0d 98 d7 73 11 65 8b 15 b9 d7 73 11 81 e2 00 01 ff 00 74
RSP: 0018:ffffc90000a08d08 EFLAGS: 00000046
RAX: ffffffff89b91509 RBX: ffff8880359f2c00 RCX: ffff888029641ec0
RDX: 0000000000010000 RSI: 0000000000000000 RDI: 18b2f83ca5ad2ffe
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffff52000141190 R12: ffff888029642a38
R13: ffff888052ace000 R14: 18b2f83ca5ad2ffe R15: 0000000000000000
FS: 00007f4a0e22e6c0(0000) GS:ffff888125387000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000555586d55a78 CR3: 0000000068ccd000 CR4: 0000000000350ef0
Call Trace:
advance_sched+0x299/0xc20 net/sched/sch_taprio.c:947
__run_hrtimer kernel/time/hrtimer.c:1930 [inline]
__hrtimer_run_queues+0x3c0/0xa20 kernel/time/hrtimer.c:1994
hrtimer_interrupt+0x44b/0x950 kernel/time/hrtimer.c:2113
local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
__sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1067
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline]
sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1061
asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:188 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x29/0x50 kernel/locking/spinlock.c:206
Code: 90 f3 0f 1e fa 53 48 89 fb 48 83 c7 18 48 8b 74 24 08 e8 5a c5 f5 f5 48 89 df e8 62 3a f6 f5 e8 cd d2 21 f6 fb bf 01 00 00 00 32 b9 e7 f5 65 8b 05 5b 7f 8d 07 85 c0 74 07 5b e9 2c 30 64 f5
RSP: 0018:ffffc900055f7710 EFLAGS: 00000206
RAX: 0000000000005517 RBX: ffff888035b8f5f8 RCX: 0000000080000001
RDX: 0000000000000006 RSI: ffffffff8dfad31b RDI: 0000000000000001
RBP: ffffc900055f7870 R08: ffffffff9030dbf7 R09: 1ffffffff2061b7e
R10: dffffc0000000000 R11: fffffbfff2061b7f R12: ffffc900055f77c0
R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000001
spin_unlock_irq include/linux/spinlock.h:402 [inline]
shmem_add_to_page_cache+0xa5e/0xd40 mm/shmem.c:928
shmem_alloc_and_add_folio+0x866/0xf80 mm/shmem.c:2001
shmem_get_folio_gfp+0x5a9/0x1670 mm/shmem.c:2564
shmem_get_folio mm/shmem.c:2670 [inline]
shmem_write_begin+0x16c/0x330 mm/shmem.c:3303
generic_perform_write+0x2e2/0x8f0 mm/filemap.c:4325
shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3478
new_sync_write fs/read_write.c:595 [inline]
vfs_write+0x61d/0xb90 fs/read_write.c:688
ksys_write+0x150/0x270 fs/read_write.c:740
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x15f/0x560 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4a0d35d68e
Code: 08 0f 85 a5 a8 ff ff 49 89 fb 48 89 f0 48 89 d7 48 89 ce 4c 89 c2 4d 89 ca 4c 8b 44 24 08 4c 8b 4c 24 10 4c 89 5c 24 08 0f 05 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 80 00 00 00 00 48 83 ec 08
RSP: 002b:00007f4a0e22dda8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007f4a0e22e6c0 RCX: 00007f4a0d35d68e
RDX: 0000000001000000 RSI: 00007f4a03000000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 00007f4a0e22dee0 R14: 00007f4a0e22dea0 R15: 00007f4a03000000
task:syz-executor state:R running task stack:22072 pid:5633 tgid:5633 ppid:5621 task_flags:0x400140 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7513
irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline]
irqentry_exit+0x14f/0x760 kernel/entry/common.c:164
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:lock_acquire+0xc0/0x350 kernel/locking/lockdep.c:5864
Code: 98 11 85 c0 0f 85 bf 00 00 00 65 48 8b 05 30 ea 97 11 83 b8 8c 0b 00 00 00 0f 85 aa 00 00 00 4c 89 74 24 10 4d 89 fe 9c 41 5f 48 c7 c7 fd 70 fc 8d e8 c3 db 07 0a 65 ff 05 ac 2f 98 11 45 31
RSP: 0018:ffffc90003adf078 EFLAGS: 00000246
RAX: ffff8880120a0000 RBX: 0000000000000000 RCX: 0000000080000001
RDX: 0000000000000000 RSI: ffffffff8176e273 RDI: 1ffffffff1d2b99c
RBP: ffffffff8176e256 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff81b0e040 R12: 0000000000000002
R13: ffffffff8e95cce0 R14: 0000000000000000 R15: 0000000000000246
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]
unwind_next_frame+0xc3/0x2550 arch/x86/kernel/unwind_orc.c:495
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
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_unref_folios+0xcec/0x1480 mm/page_alloc.c:3004
folios_put_refs+0x9ff/0xb40 mm/swap.c:1008
folio_batch_release include/linux/folio_batch.h:101 [inline]
shmem_undo_range+0x52c/0x1660 mm/shmem.c:1149
shmem_truncate_range mm/shmem.c:1277 [inline]
shmem_evict_inode+0x289/0xae0 mm/shmem.c:1407
evict+0x61e/0xb10 fs/inode.c:841
__dentry_kill+0x1a2/0x690 fs/dcache.c:718
finish_dput+0xc9/0x480 fs/dcache.c:927
__fput+0x691/0xa60 fs/file_table.c:518
task_work_run+0x1d9/0x270 kernel/task_work.c:233
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
__exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
exit_to_user_mode_loop+0xf3/0x4d0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0x560 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f09c035d68e
RSP: 002b:00007ffd8cedb908 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000555586d32500 RCX: 00007f09c035d68e
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007ffd8cedb9ac R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000010b
R13: 00000000000927c0 R14: 000000000004c4e7 R15: 00007ffd8cedba00
rcu: rcu_preempt kthread starved for 10490 jiffies! g45189 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:27736 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5388 [inline]
__schedule+0x1821/0x5740 kernel/sched/core.c:7189
__schedule_loop kernel/sched/core.c:7268 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7283
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+0x389/0x470 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:
CPU: 0 UID: 0 PID: 10521 Comm: syz.4.1452 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+0xfd4/0x13d0 kernel/smp.c:892
Code: 89 ee 83 e6 01 31 ff e8 9a 07 0c 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 45 03 0c 00 eb 37 f3 90 43 0f b6 04 2c <84> c0 75 10 41 f7 06 01 00 00 00 74 1e e8 2a 03 0c 00 eb e5 44 89
RSP: 0018:ffffc90006ff7580 EFLAGS: 00000293
RAX: 0000000000000000 RBX: ffff8880b863c148 RCX: ffff88802dd80000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc90006ff76c0 R08: ffffffff9030dbf7 R09: 1ffffffff2061b7e
R10: dffffc0000000000 R11: fffffbfff2061b7f R12: 1ffff110170e8169
R13: dffffc0000000000 R14: ffff8880b8740b48 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff888125287000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c45c17f CR3: 0000000061d80000 CR4: 0000000000350ef0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 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+0x5c3/0x10b0 arch/x86/mm/tlb.c:1451
tlb_flush arch/x86/include/asm/tlb.h:23 [inline]
tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:509 [inline]
tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:423
tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:549
exit_mmap+0x498/0x9e0 mm/mmap.c:1313
__mmput+0x118/0x430 kernel/fork.c:1178
exit_mm+0x1f6/0x2d0 kernel/exit.c:582
do_exit+0x6a2/0x22c0 kernel/exit.c:964
do_group_exit+0x21b/0x2d0 kernel/exit.c:1119
get_signal+0x1284/0x1330 kernel/signal.c:3037
arch_do_signal_or_restart+0xbc/0x840 arch/x86/kernel/signal.c:337
__exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
exit_to_user_mode_loop+0x8c/0x4d0 kernel/entry/common.c:98
__exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
do_syscall_64+0x33e/0x560 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f16d099ce59
Code: Unable to access opcode bytes at 0x7f16d099ce2f.
RSP: 002b:00007f16d19380e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: 0000000000000001 RBX: 00007f16d0c15fa8 RCX: 00007f16d099ce59
RDX: 00000000000f4240 RSI: 0000000000000081 RDI: 00007f16d0c15fac
RBP: 00007f16d0c15fa0 R08: 3fffffffffffffff R09: 0000000000000000
R10: 0000000000000024 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f16d0c16038 R14: 00007ffe82f16590 R15: 00007ffe82f16678