rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=91ac/1/0x4000000000000000 softirq=163830/163847 fqs=2 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P5625/1:b..l P28453/3:b..l rcu: (detected by 1, t=10506 jiffies, g=109105, q=392 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 4952 Comm: jbd2/sda1-8 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:advance_sched+0x38d/0xc20 net/sched/sch_taprio.c:955 Code: 00 00 00 00 48 c7 44 24 20 00 00 00 00 48 85 db 0f 85 c3 fe ff ff e8 d2 ce 0e f8 e9 0b 08 00 00 e8 c8 ce 0e f8 4c 8b 74 24 08 <4c> 89 f8 48 c1 e8 03 80 3c 28 00 74 08 4c 89 ff e8 2e 27 7a f8 49 RSP: 0018:ffffc90000007d10 EFLAGS: 00000006 RAX: ffffffff89b6e7d8 RBX: ffff888051cd2940 RCX: ffff888033455d00 RDX: 0000000000010000 RSI: 0000000000000000 RDI: 18b592be51d71e60 RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffff52000000f90 R12: ffff888033456878 R13: ffff888069622000 R14: ffff8880530a3800 R15: ffff8880530a3910 FS: 0000000000000000(0000) GS:ffff88812529c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0854f4da08 CR3: 0000000059011000 CR4: 0000000000350ef0 Call Trace: __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:update_io_ticks+0x6f/0x280 block/blk-core.c:1025 Code: 41 48 c7 44 24 28 4e c8 23 8e 48 c7 44 24 30 70 d4 8e 84 48 8d 5c 24 20 48 c1 eb 03 48 b8 f1 f1 f1 f1 f8 f3 f3 f3 4a 89 04 3b bc e1 36 fd 48 89 5c 24 18 42 c6 44 3b 04 00 48 c7 44 24 40 00 RSP: 0018:ffffc90006adf2e0 EFLAGS: 00000216 RAX: f3f3f3f8f1f1f1f1 RBX: 1ffff92000d5be60 RCX: ffffffff9a43a300 RDX: 0000000000000000 RSI: 0000000100013f94 RDI: ffff8880266eb980 RBP: ffffc90006adf3a0 R08: ffffffff90302af7 R09: 1ffffffff206055e R10: dffffc0000000000 R11: fffffbfff206055f R12: ffff8880266eb980 R13: 1ffff110055d3ba8 R14: 0000000100013f94 R15: dffffc0000000000 blk_account_io_start+0x486/0x7c0 block/blk-mq.c:1145 blk_mq_bio_to_request block/blk-mq.c:2707 [inline] blk_mq_submit_bio+0x1a5b/0x29a0 block/blk-mq.c:3214 __submit_bio+0x1c0/0x580 block/blk-core.c:635 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x2f4/0xa40 block/blk-core.c:753 journal_submit_commit_record+0x670/0x8b0 fs/jbd2/commit.c:156 jbd2_journal_commit_transaction+0x3504/0x5b00 fs/jbd2/commit.c:904 kjournald2+0x3e0/0x760 fs/jbd2/journal.c:201 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 task:syz-executor state:R running task stack:28152 pid:28453 tgid:28453 ppid:5625 task_flags:0x400040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1821/0x5740 kernel/sched/core.c:7189 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] filemap_map_pages+0x1a2a/0x2100 mm/filemap.c:3942 do_fault_around mm/memory.c:5867 [inline] do_read_fault mm/memory.c:5900 [inline] do_fault mm/memory.c:6043 [inline] do_pte_missing+0x1f38/0x33f0 mm/memory.c:4566 handle_pte_fault mm/memory.c:6427 [inline] __handle_mm_fault mm/memory.c:6565 [inline] handle_mm_fault+0x1bf2/0x3170 mm/memory.c:6734 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f08541c58d2 RSP: 002b:00007ffcb06f8060 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 00007ffcb06f8060 RCX: 00007f08541c58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007ffcb06f81ec R08: 0000000000000000 R09: 0000000000000001 R10: 00005555819a37d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 00000000001113da R15: 00007ffcb06f8240 task:syz-executor state:R running task stack:22184 pid:5625 tgid:5625 ppid:5622 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_common+0x82/0xd0 kernel/sched/core.c:7370 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:190 spin_unlock include/linux/spinlock.h:390 [inline] wp_page_copy mm/memory.c:3976 [inline] do_wp_page+0x3f15/0x4cc0 mm/memory.c:4336 handle_pte_fault mm/memory.c:6443 [inline] __handle_mm_fault mm/memory.c:6565 [inline] handle_mm_fault+0x1698/0x3170 mm/memory.c:6734 do_user_addr_fault+0xa73/0x1340 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6a/0xc0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f08541b8350 RSP: 002b:00007ffcb06f8088 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000b62 RCX: 00007f085413e4a7 RDX: 0000000000000000 RSI: 00007ffcb06f8060 RDI: 0000000000000002 RBP: 00007ffcb06f81ec R08: 00007f0854f48060 R09: 0000000000000000 R10: 0000000000000008 R11: 0000000000000246 R12: 0000000000000001 R13: ffffffffffffffe8 R14: 0000000000000019 R15: 00007ffcb06f8240 rcu: rcu_preempt kthread starved for 10496 jiffies! g109105 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:27536 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: 1 UID: 0 PID: 27051 Comm: syz-executor 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:ffffc900038a7560 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b873c188 RCX: ffff88804c95dd00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc900038a7688 R08: ffffffff90302af7 R09: 1ffffffff206055e R10: dffffc0000000000 R11: fffffbfff206055f R12: 1ffff110170c8591 R13: dffffc0000000000 R14: ffff8880b8642c88 R15: 0000000000000000 FS: 0000555556a74500(0000) GS:ffff88812539c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000110c3e80a0 CR3: 000000003491e000 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 dup_mmap+0x17b0/0x1da0 mm/mmap.c:1905 dup_mm kernel/fork.c:1534 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1586 copy_process+0x1f1c/0x4440 kernel/fork.c:2264 kernel_clone+0x2d7/0x940 kernel/fork.c:2722 __do_sys_clone kernel/fork.c:2863 [inline] __se_sys_clone kernel/fork.c:2847 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2847 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x174/0x580 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f50689c58d2 Code: 89 e7 e8 71 8b f7 ff 45 31 c0 31 d2 31 f6 64 48 8b 04 25 10 00 00 00 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 66 89 c5 85 c0 75 3b 64 48 8b 04 25 10 00 00 RSP: 002b:00007fff84999ee0 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fff84999ee0 RCX: 00007f50689c58d2 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fff8499a06c R08: 0000000000000000 R09: 0000000000000001 R10: 0000555556a747d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 0000000000110d52 R15: 00007fff8499a0c0