rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12/1:b..l
rcu: (detected by 0, t=10502 jiffies, g=23713, q=586 ncpus=2)
task:kworker/u8:0 state:R running task stack:22880 pid:12 tgid:12 ppid:2 task_flags:0x4248060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-8:0)
Call Trace:
context_switch kernel/sched/core.c:5352 [inline]
__schedule+0x165c/0x5560 kernel/sched/core.c:6964
preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7292
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:__read_once_word_nocheck+0x3/0x10 include/asm-generic/rwonce.h:67
Code: 00 48 ba 00 00 00 00 00 fc ff df e9 88 fc ff ff 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 48 8b 07 cc cc cc cc cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90
RSP: 0018:ffffc90000116390 EFLAGS: 00000202
RAX: ffffffff82518849 RBX: ffffc90000117758 RCX: 1ffff92000022c01
RDX: ffffffff90daae4e RSI: 0000000000000002 RDI: ffffc90000117758
RBP: 1ffff92000022c8e R08: 0000000000000001 R09: ffffffff8e95d7e0
R10: ffffc900001164b8 R11: ffffffff81b1dc30 R12: ffffc90000118000
R13: 1ffff92000022c8f R14: ffffc90000116468 R15: ffffc90000110000
deref_stack_reg arch/x86/kernel/unwind_orc.c:422 [inline]
unwind_next_frame+0xed7/0x2550 arch/x86/kernel/unwind_orc.c:614
arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25
stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
unpoison_slab_object mm/kasan/common.c:340 [inline]
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:366
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]
kmem_cache_alloc_noprof+0x2bc/0x650 mm/slub.c:4905
bio_alloc_bioset+0x1a0/0xc10 block/bio.c:548
bio_alloc include/linux/bio.h:373 [inline]
io_submit_init_bio fs/ext4/page-io.c:428 [inline]
io_submit_add_bh fs/ext4/page-io.c:464 [inline]
ext4_bio_write_folio+0x1044/0x1ea0 fs/ext4/page-io.c:603
mpage_process_page_bufs+0x6d5/0x8e0 fs/ext4/inode.c:2194
mpage_prepare_extent_to_map+0xe1b/0x16f0 fs/ext4/inode.c:2733
ext4_do_writepages+0xbac/0x4670 fs/ext4/inode.c:2874
ext4_writepages+0x241/0x3b0 fs/ext4/inode.c:3022
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x10e0 fs/fs-writeback.c:1750
writeback_sb_inodes+0x979/0x19d0 fs/fs-writeback.c:2042
__writeback_inodes_wb+0x111/0x240 fs/fs-writeback.c:2118
wb_writeback+0x459/0xb00 fs/fs-writeback.c:2229
wb_check_old_data_flush fs/fs-writeback.c:2333 [inline]
wb_do_writeback fs/fs-writeback.c:2386 [inline]
wb_workfn+0xb12/0xf10 fs/fs-writeback.c:2414
process_one_work+0x9a3/0x1710 kernel/workqueue.c:3288
process_scheduled_works kernel/workqueue.c:3379 [inline]
worker_thread+0xba8/0x11e0 kernel/workqueue.c:3465
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
rcu: rcu_preempt kthread starved for 10475 jiffies! g23713 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:27704 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5352 [inline]
__schedule+0x165c/0x5560 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7047 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7062
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+0x51e/0xb90 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: 7339 Comm: syz.1.220 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0x47/0x80 kernel/locking/spinlock.c:198
Code: f7 e8 6d df e4 f5 f7 c3 00 02 00 00 74 05 e8 60 38 10 f6 9c 58 a9 00 02 00 00 75 27 f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 84 7d d6 f5 65 8b 05 9d 58 84 07 85 c0 74 18 5b 41 5e e9 41 48
RSP: 0018:ffffc90004a97428 EFLAGS: 00000206
RAX: 0000000000000006 RBX: 0000000000000246 RCX: 0000000080000001
RDX: 0000000000000007 RSI: ffffffff8e05f4c1 RDI: 0000000000000001
RBP: ffffc90004a975d0 R08: ffffffff903444f7 R09: 1ffffffff206889e
R10: dffffc0000000000 R11: fffffbfff206889f R12: dffffc0000000000
R13: 0000000000000000 R14: ffff8880b8428280 R15: ffff88807e6a4760
FS: 00007f5ebcee56c0(0000) GS:ffff888124ff3000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f33247e8640 CR3: 00000000755d4000 CR4: 00000000003526f0
Call Trace:
hrtimer_start include/linux/hrtimer.h:220 [inline]
stimer_start arch/x86/kvm/hyperv.c:-1 [inline]
kvm_hv_process_stimers+0xdfe/0x1750 arch/x86/kvm/hyperv.c:893
vcpu_enter_guest arch/x86/kvm/x86.c:11310 [inline]
vcpu_run+0x271c/0x7860 arch/x86/kvm/x86.c:11759
kvm_arch_vcpu_ioctl_run+0x11e6/0x20d0 arch/x86/kvm/x86.c:12107
kvm_vcpu_ioctl+0xa62/0xfd0 virt/kvm/kvm_main.c:4478
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl+0xfc/0x170 fs/ioctl.c:583
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f5ebbf9aef9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f5ebcee5028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f5ebc205fa0 RCX: 00007f5ebbf9aef9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f5ebc02fee0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f5ebc206038 R14: 00007f5ebc205fa0 R15: 00007ffe502c2e68