rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6025/1:b..l
rcu: (detected by 0, t=10504 jiffies, g=12829, q=408 ncpus=2)
task:syz.4.13 state:R running task stack:26920 pid:6025 tgid:6024 ppid:5844 task_flags:0x400040 flags:0x00004002
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 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:100 [inline]
RIP: 0010:orc_find arch/x86/kernel/unwind_orc.c:227 [inline]
RIP: 0010:unwind_next_frame+0x12ea/0x2390 arch/x86/kernel/unwind_orc.c:494
Code: 40 45 08 8b 89 de e8 45 7e b4 ff e9 43 06 00 00 49 89 d5 48 89 d5 48 89 d8 48 29 e8 48 89 c1 48 c1 f9 02 48 c1 e8 3f 48 01 c8 <48> 83 e0 fe 4c 8d 3c 45 00 00 00 00 49 01 ef 4c 89 f8 48 c1 e8 03
RSP: 0018:ffffc90005e67178 EFLAGS: 00000246
RAX: 0000000000000000 RBX: ffffffff8f2a8644 RCX: 0000000000000000
RDX: ffffffff8f2a8644 RSI: ffffffff8f9deb26 RDI: ffffffff8b621620
RBP: ffffffff8f2a8644 R08: 0000000000000022 R09: ffffffff8172c165
R10: ffffc90005e67298 R11: ffffffff81aaefe0 R12: ffffffff8100012f
R13: ffffffff8f2a8644 R14: ffffc90005e67248 R15: ffffffff8f2a8648
arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122
save_stack+0xf7/0x1f0 mm/page_owner.c:156
__set_page_owner+0x8d/0x490 mm/page_owner.c:329
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
prep_new_page mm/page_alloc.c:1859 [inline]
get_page_from_freelist+0x2119/0x21b0 mm/page_alloc.c:3858
__alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
alloc_pages_mpol+0xd1/0x380 mm/mempolicy.c:2416
folio_alloc_mpol_noprof+0x39/0xe0 mm/mempolicy.c:2435
shmem_alloc_folio mm/shmem.c:1908 [inline]
shmem_alloc_and_add_folio mm/shmem.c:1947 [inline]
shmem_get_folio_gfp+0x633/0x1a70 mm/shmem.c:2597
shmem_get_folio mm/shmem.c:2703 [inline]
shmem_write_begin+0xef/0x2a0 mm/shmem.c:3353
generic_perform_write+0x29d/0x8c0 mm/filemap.c:4175
shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3528
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d5/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
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: 0033:0x7fa5353bd97f
RSP: 002b:00007fa533625df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fa5353bd97f
RDX: 0000000001000000 RSI: 00007fa52b206000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005a9d
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007fa533625ef0 R14: 00007fa533625eb0 R15: 00007fa52b206000
rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g12829 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402
rcu: Possible timer handling issue on cpu=1 timer-softirq=4487
rcu: rcu_preempt kthread starved for 10502 jiffies! g12829 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27224 pid:18 tgid:18 ppid:2 task_flags:0x208040 flags:0x00004000
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 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+0x436/0x7d0 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: 6021 Comm: syz.1.12 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:native_halt+0x18/0x30 arch/x86/include/asm/irqflags.h:55
Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa e8 e7 1b 4c 00 66 90 e8 e0 1b 4c 00 0f 00 2d 79 e4 95 09 f4 53 91 88 09 cc f3 0f 1e fa e8 c9 1b 4c 00 f4 e9 43 91 88 09 cc
RSP: 0018:ffffc90005506f78 EFLAGS: 000000c7
RAX: ffffffff81724f40 RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc9000e5fa000 RSI: 00000000000067dc RDI: 00000000000067dd
RBP: ffffc90005507050 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff91ffffafb47 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000aa0df4
FS: 00007f99cd6966c0(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f429788ed9c CR3: 000000003072a000 CR4: 00000000003526f0
Call Trace:
halt arch/x86/include/asm/paravirt.h:112 [inline]
kvm_wait+0x188/0x290 arch/x86/kernel/kvm.c:1058
pv_wait arch/x86/include/asm/paravirt.h:569 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
__pv_queued_spin_lock_slowpath+0x7bf/0xb60 kernel/locking/qspinlock.c:325
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x144/0x2c0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
___slab_alloc+0xbf6/0xdc0 mm/slub.c:3951
__slab_alloc mm/slub.c:3992 [inline]
__slab_alloc_node mm/slub.c:4067 [inline]
slab_alloc_node mm/slub.c:4228 [inline]
kmem_cache_alloc_noprof+0xe6/0x310 mm/slub.c:4247
mempool_init_node+0x210/0x4f0 mm/mempool.c:221
mempool_init_noprof+0x3a/0x50 mm/mempool.c:250
bioset_init+0x2f3/0x7a0 block/bio.c:1809
bch2_fs_fsio_init+0x28/0x50 fs/bcachefs/fs-io.c:1095
bch2_fs_alloc fs/bcachefs/super.c:1008 [inline]
bch2_fs_open+0x231a/0x26e0 fs/bcachefs/super.c:2433
bch2_fs_get_tree+0x44f/0x1520 fs/bcachefs/fs.c:2472
vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4324
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: 0033:0x7f99cf43066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f99cd695e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f99cd695ef0 RCX: 00007f99cf43066a
RDX: 0000200000000000 RSI: 0000200000000080 RDI: 00007f99cd695eb0
RBP: 0000200000000000 R08: 00007f99cd695ef0 R09: 0000000001004001
R10: 0000000001004001 R11: 0000000000000246 R12: 0000200000000080
R13: 00007f99cd695eb0 R14: 0000000000024c74 R15: 0000200000000140
watchdog: BUG: soft lockup - CPU#0 stuck for 246s! [kworker/u8:6:758]
Modules linked in:
irq event stamp: 551464
hardirqs last enabled at (551463): [] irqentry_exit+0x74/0x90 kernel/entry/common.c:200
hardirqs last disabled at (551464): [] sysvec_apic_timer_interrupt+0xe/0xc0 arch/x86/kernel/apic/apic.c:1050
softirqs last enabled at (500908): [] __local_bh_enable_ip+0x1a4/0x270 kernel/softirq.c:262
softirqs last disabled at (500902): [] local_bh_disable include/linux/bottom_half.h:20 [inline]
softirqs last disabled at (500902): [] spin_lock_bh include/linux/spinlock_rt.h:87 [inline]
softirqs last disabled at (500902): [] nsim_dev_trap_report drivers/net/netdevsim/dev.c:831 [inline]
softirqs last disabled at (500902): [] nsim_dev_trap_report_work+0x72e/0xbc0 drivers/net/netdevsim/dev.c:866
CPU: 0 UID: 0 PID: 758 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline]
RIP: 0010:smp_call_function_many_cond+0xed4/0x12d0 kernel/smp.c:877
Code: 45 8b 2c 24 44 89 ee 83 e6 01 31 ff e8 65 60 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 a0 5b 0b 00 eb 38 f3 90 <42> 0f b6 04 2b 84 c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 84 5b
RSP: 0018:ffffc9000432f660 EFLAGS: 00000293
RAX: ffffffff81b30f9c RBX: 1ffff110171283a9 RCX: ffff888024415940
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc9000432f7e0 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff1e3ac47 R12: ffff8880b8941d48
R13: dffffc0000000000 R14: ffff8880b883bcc0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f403d2ce000 CR3: 000000000d7a6000 CR4: 00000000003526f0
Call Trace:
on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044
on_each_cpu include/linux/smp.h:71 [inline]
smp_text_poke_sync_each_cpu arch/x86/kernel/alternative.c:2653 [inline]
smp_text_poke_batch_finish+0x5f9/0x1130 arch/x86/kernel/alternative.c:2863
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:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x70e/0x8a0 kernel/kthread.c:463
ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 6021 Comm: syz.1.12 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:native_halt+0x18/0x30 arch/x86/include/asm/irqflags.h:55
Code: 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa e8 e7 1b 4c 00 66 90 e8 e0 1b 4c 00 0f 00 2d 79 e4 95 09 f4 53 91 88 09 cc f3 0f 1e fa e8 c9 1b 4c 00 f4 e9 43 91 88 09 cc
RSP: 0018:ffffc90005506f78 EFLAGS: 000000c7
RAX: ffffffff81724f40 RBX: 0000000000000003 RCX: 0000000000080000
RDX: ffffc9000e5fa000 RSI: 00000000000067e0 RDI: 00000000000067e1
RBP: ffffc90005507050 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffff91ffffafb47 R12: dffffc0000000000
R13: 0000000000000200 R14: 0000000000000003 R15: 1ffff92000aa0df4
FS: 00007f99cd6966c0(0000) GS:ffff8881269bc000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f429788ed9c CR3: 000000003072a000 CR4: 00000000003526f0
Call Trace:
halt arch/x86/include/asm/paravirt.h:112 [inline]
kvm_wait+0x188/0x290 arch/x86/kernel/kvm.c:1058
pv_wait arch/x86/include/asm/paravirt.h:569 [inline]
pv_wait_head_or_lock kernel/locking/qspinlock_paravirt.h:466 [inline]
__pv_queued_spin_lock_slowpath+0x7bf/0xb60 kernel/locking/qspinlock.c:325
pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:557 [inline]
queued_spin_lock_slowpath+0x43/0x50 arch/x86/include/asm/qspinlock.h:51
queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
do_raw_spin_lock+0x21f/0x290 kernel/locking/spinlock_debug.c:116
__raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
_raw_spin_lock_irqsave+0xb3/0xf0 kernel/locking/spinlock.c:162
rtlock_slowlock kernel/locking/rtmutex.c:1894 [inline]
rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
__rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
rt_spin_lock+0x144/0x2c0 kernel/locking/spinlock_rt.c:57
spin_lock include/linux/spinlock_rt.h:44 [inline]
___slab_alloc+0xbf6/0xdc0 mm/slub.c:3951
__slab_alloc mm/slub.c:3992 [inline]
__slab_alloc_node mm/slub.c:4067 [inline]
slab_alloc_node mm/slub.c:4228 [inline]
kmem_cache_alloc_noprof+0xe6/0x310 mm/slub.c:4247
mempool_init_node+0x210/0x4f0 mm/mempool.c:221
mempool_init_noprof+0x3a/0x50 mm/mempool.c:250
bioset_init+0x2f3/0x7a0 block/bio.c:1809
bch2_fs_fsio_init+0x28/0x50 fs/bcachefs/fs-io.c:1095
bch2_fs_alloc fs/bcachefs/super.c:1008 [inline]
bch2_fs_open+0x231a/0x26e0 fs/bcachefs/super.c:2433
bch2_fs_get_tree+0x44f/0x1520 fs/bcachefs/fs.c:2472
vfs_get_tree+0x8f/0x2b0 fs/super.c:1815
do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4324
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: 0033:0x7f99cf43066a
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f99cd695e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f99cd695ef0 RCX: 00007f99cf43066a
RDX: 0000200000000000 RSI: 0000200000000080 RDI: 00007f99cd695eb0
RBP: 0000200000000000 R08: 00007f99cd695ef0 R09: 0000000001004001
R10: 0000000001004001 R11: 0000000000000246 R12: 0000200000000080
R13: 00007f99cd695eb0 R14: 0000000000024c74 R15: 0000200000000140