rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P6665/3:b..l P3475/1:b..l P2226/1:b..l rcu: (detected by 0, t=10502 jiffies, g=17189, q=892 ncpus=2) task:kworker/1:1H state:R running task stack:27864 pid:2226 tgid:2226 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: kblockd blk_mq_run_work_fn Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6020 kernel/sched/core.c:6907 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7091 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 rcu_read_unlock_sched include/linux/rcupdate.h:975 [inline] pfn_valid include/linux/mmzone.h:2207 [inline] bvec_phys+0x550/0x5c0 include/linux/bvec.h:295 blk_map_iter_next+0x266/0xc80 block/blk-mq-dma.c:37 __blk_rq_map_sg+0x1ac/0x780 block/blk-mq-dma.c:292 scsi_alloc_sgtables+0x216/0xf10 drivers/scsi/scsi_lib.c:1161 sd_setup_read_write_cmnd drivers/scsi/sd.c:1372 [inline] sd_init_command+0x2ea/0x3b90 drivers/scsi/sd.c:1494 scsi_prepare_cmd drivers/scsi/scsi_lib.c:1729 [inline] scsi_queue_rq+0x11e9/0x3b70 drivers/scsi/scsi_lib.c:1877 blk_mq_dispatch_rq_list+0x422/0x1e70 block/blk-mq.c:2148 __blk_mq_do_dispatch_sched block/blk-mq-sched.c:168 [inline] blk_mq_do_dispatch_sched block/blk-mq-sched.c:182 [inline] __blk_mq_sched_dispatch_requests+0xcea/0x1620 block/blk-mq-sched.c:307 blk_mq_sched_dispatch_requests+0xd7/0x1c0 block/blk-mq-sched.c:329 blk_mq_run_work_fn+0x1fe/0x380 block/blk-mq.c:2562 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:kworker/u8:7 state:R running task stack:23576 pid:3475 tgid:3475 ppid:2 task_flags:0x24248060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-8:0) Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6020 kernel/sched/core.c:6907 preempt_schedule_notrace+0x5f/0xd0 kernel/sched/core.c:7184 preempt_schedule_notrace_thunk+0x16/0x30 arch/x86/entry/thunk.S:13 rcu_is_watching+0x8e/0xc0 kernel/rcu/tree.c:753 trace_lock_acquire include/trace/events/lock.h:24 [inline] lock_acquire+0x2c4/0x330 kernel/locking/lockdep.c:5831 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] percpu_ref_put_many include/linux/percpu-refcount.h:330 [inline] percpu_ref_put include/linux/percpu-refcount.h:351 [inline] blk_mq_dispatch_list+0x56c/0x1360 block/blk-mq.c:2953 blk_mq_flush_plug_list block/blk-mq.c:2997 [inline] blk_mq_flush_plug_list+0x130/0x600 block/blk-mq.c:2969 __blk_flush_plug+0x2c4/0x4b0 block/blk-core.c:1230 blk_flush_plug include/linux/blkdev.h:1205 [inline] io_schedule_prepare kernel/sched/core.c:7800 [inline] io_schedule+0x85/0xf0 kernel/sched/core.c:7830 rq_qos_wait+0x22d/0x330 block/blk-rq-qos.c:307 __wbt_wait block/blk-wbt.c:598 [inline] wbt_wait+0x18a/0x310 block/blk-wbt.c:658 __rq_qos_throttle+0x56/0xa0 block/blk-rq-qos.c:66 rq_qos_throttle block/blk-rq-qos.h:164 [inline] rq_qos_throttle block/blk-rq-qos.h:160 [inline] blk_mq_get_new_requests block/blk-mq.c:3063 [inline] blk_mq_submit_bio+0xb68/0x2b90 block/blk-mq.c:3214 __submit_bio+0x1e1/0x6c0 block/blk-core.c:635 __submit_bio_noacct_mq block/blk-core.c:722 [inline] submit_bio_noacct_nocheck+0x50f/0xbb0 block/blk-core.c:753 submit_bio_noacct+0xd17/0x1fb0 block/blk-core.c:884 blk_crypto_submit_bio include/linux/blk-crypto.h:203 [inline] ext4_io_submit+0xf7/0x1a0 fs/ext4/page-io.c:405 io_submit_add_bh fs/ext4/page-io.c:446 [inline] ext4_bio_write_folio+0x766/0x1dd0 fs/ext4/page-io.c:590 mpage_process_page_bufs+0x473/0x8d0 fs/ext4/inode.c:2191 mpage_prepare_extent_to_map+0xb50/0x1920 fs/ext4/inode.c:2730 ext4_do_writepages+0xa07/0x3df0 fs/ext4/inode.c:2871 ext4_writepages+0x347/0x790 fs/ext4/inode.c:3019 do_writepages+0x278/0x600 mm/page-writeback.c:2554 __writeback_single_inode+0x164/0x1220 fs/fs-writeback.c:1750 writeback_sb_inodes+0x72e/0x1b90 fs/fs-writeback.c:2041 __writeback_inodes_wb+0xf8/0x2d0 fs/fs-writeback.c:2118 wb_writeback+0x6b4/0xab0 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+0x885/0xbb0 fs/fs-writeback.c:2414 process_one_work+0x9c2/0x1840 kernel/workqueue.c:3275 process_scheduled_works kernel/workqueue.c:3358 [inline] worker_thread+0x5da/0xe40 kernel/workqueue.c:3439 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 task:dhcpcd-run-hook state:R running task stack:27192 pid:6665 tgid:6665 ppid:5468 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6020 kernel/sched/core.c:6907 preempt_schedule_common+0x42/0xc0 kernel/sched/core.c:7091 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+0x3e/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] filemap_map_pages+0x15b9/0x2110 mm/filemap.c:3931 do_fault_around mm/memory.c:5748 [inline] do_read_fault mm/memory.c:5781 [inline] do_fault+0x9e5/0x1a00 mm/memory.c:5924 do_pte_missing mm/memory.c:4469 [inline] handle_pte_fault mm/memory.c:6308 [inline] __handle_mm_fault+0x180f/0x2b60 mm/memory.c:6446 handle_mm_fault+0x36d/0xa20 mm/memory.c:6615 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f15ec54b270 RSP: 002b:00007ffd1451e740 EFLAGS: 00010246 RAX: 00007f15ec561260 RBX: 00007f15ec555b20 RCX: 00007ffd14520e87 RDX: 0000000000000047 RSI: 00007ffd14520e8c RDI: 00007f15ec5630a7 RBP: 00007f15ec56c300 R08: 00007ffd14520e87 R09: 00005567659d5040 R10: 0000000000000000 R11: 00007ffd1451e760 R12: 00007ffd1451eda8 R13: 00007f15ec56eda0 R14: 0000000000000000 R15: 00007ffd1451e760 rcu: rcu_preempt kthread starved for 10602 jiffies! g17189 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:28680 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0xfee/0x6020 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7004 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:467 ret_from_fork+0x754/0xd80 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: Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6664 Comm: syz.4.79 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:arch_test_bit arch/x86/include/asm/bitops.h:233 [inline] RIP: 0010:_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:142 [inline] RIP: 0010:hlock_class kernel/locking/lockdep.c:234 [inline] RIP: 0010:mark_lock+0x47/0xa20 kernel/locking/lockdep.c:4731 Code: 8b 1d 15 05 26 12 48 89 5c 24 68 89 d3 83 fa 08 74 6d 41 be 01 00 00 00 89 d9 41 d3 e6 4d 63 f6 41 0f b7 44 24 20 66 25 ff 1f <0f> b7 c0 48 0f a3 05 7e dc 2c 14 73 5b 48 8d 04 80 48 8d 04 80 48 RSP: 0018:ffffc90000a087e0 EFLAGS: 00000002 RAX: 0000000000000007 RBX: 0000000000000009 RCX: 0000000000000003 RDX: 0000000000000008 RSI: ffff888034423010 RDI: ffff888034422480 RBP: ffffc90000a08880 R08: 0000000000000000 R09: 0000000000000007 R10: 0000000000000003 R11: 0000000000000001 R12: ffff888034423010 R13: ffff888034422480 R14: 0000000000000200 R15: 0000000000000003 FS: 00007fa1437fe6c0(0000) GS:ffff88812448b000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ff63fff CR3: 000000007c7c0000 CR4: 00000000003526f0 Call Trace: mark_usage kernel/locking/lockdep.c:4674 [inline] __lock_acquire+0x4a5/0x2630 kernel/locking/lockdep.c:5191 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x17c/0x330 kernel/locking/lockdep.c:5825 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] class_rcu_constructor include/linux/rcupdate.h:1193 [inline] unwind_next_frame+0xd1/0x1ea0 arch/x86/kernel/unwind_orc.c:495 arch_stack_walk+0x94/0xf0 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 unpoison_slab_object mm/kasan/common.c:340 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:366 kasan_slab_alloc include/linux/kasan.h:253 [inline] slab_post_alloc_hook mm/slub.c:4459 [inline] slab_alloc_node mm/slub.c:4788 [inline] kmem_cache_alloc_noprof+0x241/0x6e0 mm/slub.c:4795 sigqueue_alloc kernel/signal.c:455 [inline] __send_signal_locked+0x155/0x12d0 kernel/signal.c:1087 do_send_sig_info kernel/signal.c:1269 [inline] group_send_sig_info+0x2a4/0x300 kernel/signal.c:1419 do_bpf_send_signal+0xe1/0x1e0 kernel/trace/bpf_trace.c:813 irq_work_single+0x1c0/0x270 kernel/irq_work.c:221 irq_work_run_list+0x96/0xd0 kernel/irq_work.c:252 irq_work_run+0x58/0xd0 kernel/irq_work.c:261 __sysvec_irq_work+0x80/0x3b0 arch/x86/kernel/irq_work.c:22 instr_sysvec_irq_work arch/x86/kernel/irq_work.c:17 [inline] sysvec_irq_work+0x9e/0xc0 arch/x86/kernel/irq_work.c:17 asm_sysvec_irq_work+0x1a/0x20 arch/x86/include/asm/idtentry.h:733 RIP: 0010:arch_static_branch arch/x86/include/asm/jump_label.h:37 [inline] RIP: 0010:native_write_msr arch/x86/include/asm/msr.h:139 [inline] RIP: 0010:wrmsrq arch/x86/include/asm/msr.h:199 [inline] RIP: 0010:native_apic_msr_write arch/x86/include/asm/apic.h:208 [inline] RIP: 0010:native_apic_msr_write+0x28/0x40 arch/x86/include/asm/apic.h:202 Code: 90 90 f3 0f 1e fa 8d 87 30 ff ff ff 83 e0 ef 74 20 89 f8 83 e0 ef 83 f8 20 74 16 c1 ef 04 31 d2 89 f0 8d 8f 00 08 00 00 0f 30 <66> 90 c3 cc cc cc cc c3 cc cc cc cc 89 f6 31 d2 89 cf e9 c1 a2 6c RSP: 0018:ffffc90003fefbd0 EFLAGS: 00000246 RAX: 00000000000000f6 RBX: 0000000000000001 RCX: 000000000000083f RDX: 0000000000000000 RSI: 00000000000000f6 RDI: 000000000000003f RBP: ffff8880b85316e0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: 1ffff920007fdf7f R13: 1ffff110170a6201 R14: 0000000000000000 R15: 0000000000000000 __apic_send_IPI_self arch/x86/include/asm/apic.h:455 [inline] arch_irq_work_raise+0x4f/0x70 arch/x86/kernel/irq_work.c:31 irq_work_raise kernel/irq_work.c:84 [inline] __irq_work_queue_local+0x1d2/0x540 kernel/irq_work.c:112 irq_work_queue kernel/irq_work.c:124 [inline] irq_work_queue+0xab/0x100 kernel/irq_work.c:116 bpf_send_signal_common+0x3a6/0x540 kernel/trace/bpf_trace.c:871 ____bpf_send_signal kernel/trace/bpf_trace.c:880 [inline] bpf_send_signal+0x1d/0x30 kernel/trace/bpf_trace.c:878 bpf_prog_948316cddd0b7b1c+0x41/0x49 bpf_dispatcher_nop_func include/linux/bpf.h:1402 [inline] __bpf_prog_run include/linux/filter.h:723 [inline] bpf_prog_run include/linux/filter.h:730 [inline] __bpf_trace_run kernel/trace/bpf_trace.c:2089 [inline] bpf_trace_run2+0x213/0x570 kernel/trace/bpf_trace.c:2130 __bpf_trace_sys_enter+0x37/0x60 include/trace/events/syscalls.h:18 __traceiter_sys_enter+0x30/0x50 include/trace/events/syscalls.h:18 __do_trace_sys_enter include/trace/events/syscalls.h:18 [inline] trace_sys_enter include/trace/events/syscalls.h:18 [inline] trace_syscall_enter+0xb0/0x110 kernel/entry/syscall-common.c:12 syscall_trace_enter include/linux/entry-common.h:121 [inline] syscall_enter_from_user_mode_work include/linux/entry-common.h:156 [inline] syscall_enter_from_user_mode include/linux/entry-common.h:187 [inline] do_syscall_64+0x71a/0xf80 arch/x86/entry/syscall_64.c:90 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa14413c319 Code: 11 06 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 c7 c0 0f 00 00 00 0f 05 <0f> 1f 80 00 00 00 00 48 81 ec 48 01 00 00 49 89 d0 64 48 8b 0c 25 RSP: 002b:00007fa1437fd400 EFLAGS: 00000246 ORIG_RAX: 000000000000000f RAX: ffffffffffffffda RBX: 00007fa144405fa8 RCX: 00007fa14413c319 RDX: 00007fa1437fd400 RSI: 00007fa1437fd530 RDI: 0000000000000011 RBP: 00007fa144405fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000005 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fa144406038 R14: 00007ffd4c965a90 R15: 00007ffd4c965b78