rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=588c/1/0x4000000000000000 softirq=85548/85556 fqs=9 rcu: (detected by 1, t=10502 jiffies, g=80057, q=532 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 16394 Comm: syz.0.2760 Not tainted 6.12.0-syzkaller-09435-g2c22dc1ee3a1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:__lock_acquire+0x166/0x2100 Code: 04 30 84 c0 48 89 54 24 20 0f 85 56 16 00 00 83 3d 1e 4b d1 18 00 75 09 83 fa 30 0f 83 5f 14 00 00 89 6c 24 58 4c 89 64 24 40 <8b> ac 24 d8 00 00 00 48 c7 c0 40 77 c9 93 48 29 c3 48 c1 fb 03 48 RSP: 0018:ffffc90000007a10 EFLAGS: 00000083 RAX: 0000000000000004 RBX: ffffffff93c99108 RCX: ffffffff9a426903 RDX: 0000000000000003 RSI: dffffc0000000000 RDI: ffff88802fb228d8 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001 R10: dffffc0000000000 R11: fffffbfff203c70f R12: ffff88802fb21e00 R13: 0000000000000000 R14: 0000000000000000 R15: ffffffff8e93c520 FS: 00007fe9c87596c0(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f5f2dd062d8 CR3: 0000000059338000 CR4: 0000000000350ef0 Call Trace: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5849 rcu_lock_acquire include/linux/rcupdate.h:337 [inline] rcu_read_lock include/linux/rcupdate.h:849 [inline] advance_sched+0xa1e/0xca0 net/sched/sch_taprio.c:985 __run_hrtimer kernel/time/hrtimer.c:1739 [inline] __hrtimer_run_queues+0x59d/0xd50 kernel/time/hrtimer.c:1803 hrtimer_interrupt+0x403/0xa40 kernel/time/hrtimer.c:1865 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1038 [inline] __sysvec_apic_timer_interrupt+0x112/0x420 arch/x86/kernel/apic/apic.c:1055 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1049 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0xd8/0x140 kernel/locking/spinlock.c:194 Code: 9c 8f 44 24 20 42 80 3c 23 00 74 08 4c 89 f7 e8 3e de 24 f6 f6 44 24 21 02 75 52 41 f7 c7 00 02 00 00 74 01 fb bf 01 00 00 00 a3 08 88 f5 65 8b 05 94 ed 27 74 85 c0 74 43 48 c7 04 24 0e 36 RSP: 0018:ffffc90003567540 EFLAGS: 00000206 RAX: 711b4c4432012800 RBX: 1ffff920006aceac RCX: ffffffff81718fba RDX: dffffc0000000000 RSI: ffffffff8c0ad8a0 RDI: 0000000000000001 RBP: ffffc900035675d0 R08: ffffffff9431f8df R09: 1ffffffff2863f1b R10: dffffc0000000000 R11: fffffbfff2863f1c R12: dffffc0000000000 R13: 1ffff920006acea8 R14: ffffc90003567560 R15: 0000000000000246 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline] unlock_page_lruvec_irqrestore include/linux/memcontrol.h:1520 [inline] folio_batch_move_lru+0x42b/0x4e0 mm/swap.c:174 __folio_batch_add_and_move+0x5cb/0xf00 mm/swap.c:196 shmem_alloc_and_add_folio+0xdd6/0x13d0 mm/shmem.c:1892 shmem_get_folio_gfp+0x5a9/0x20a0 mm/shmem.c:2355 shmem_get_folio mm/shmem.c:2461 [inline] shmem_write_begin+0x17e/0x460 mm/shmem.c:3117 generic_perform_write+0x346/0x6d0 mm/filemap.c:4055 shmem_file_write_iter+0xf9/0x120 mm/shmem.c:3293 new_sync_write fs/read_write.c:586 [inline] vfs_write+0xaed/0xd30 fs/read_write.c:679 ksys_write+0x18f/0x2b0 fs/read_write.c:731 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe9c797d2ff Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 c9 8d 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 1c 8e 02 00 48 RSP: 002b:00007fe9c8758df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007fe9c797d2ff RDX: 0000000001000000 RSI: 00007fe9bd200000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000970f R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003 R13: 00007fe9c8758ef0 R14: 00007fe9c8758eb0 R15: 00007fe9bd200000 rcu: rcu_preempt kthread starved for 10484 jiffies! g80057 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:25976 pid:17 tgid:17 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5369 [inline] __schedule+0x1850/0x4c30 kernel/sched/core.c:6756 __schedule_loop kernel/sched/core.c:6833 [inline] schedule+0x14b/0x320 kernel/sched/core.c:6848 schedule_timeout+0x15a/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x2df/0x1330 kernel/rcu/tree.c:2045 rcu_gp_kthread+0xa7/0x3b0 kernel/rcu/tree.c:2247 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 rcu: Stack dump where RCU GP kthread last ran: CPU: 1 UID: 0 PID: 19 Comm: rcu_exp_gp_kthr Not tainted 6.12.0-syzkaller-09435-g2c22dc1ee3a1 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024 RIP: 0010:csd_lock_wait kernel/smp.c:340 [inline] RIP: 0010:csd_lock kernel/smp.c:355 [inline] RIP: 0010:smp_call_function_single+0x311/0x1990 kernel/smp.c:666 Code: 75 14 e8 32 25 0c 00 4d 89 ef 49 bd 00 00 00 00 00 fc ff df eb 45 4d 89 ef 49 bd 00 00 00 00 00 fc ff df f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 fc 24 0c 00 eb e4 44 RSP: 0018:ffffc90000187a60 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170e7f41 RCX: ffff88801ce93c00 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000187be8 R08: ffffffff8189b7e3 R09: 1ffffffff203c70e R10: dffffc0000000000 R11: fffffbfff203c70f R12: ffff8880b873fa08 R13: dffffc0000000000 R14: ffff8880b873fa00 R15: ffff8880b873fa18 FS: 0000000000000000(0000) GS:ffff8880b8700000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f44a5937bac CR3: 000000005d4b6000 CR4: 0000000000350ef0 Call Trace: __sync_rcu_exp_select_node_cpus kernel/rcu/tree_exp.h:413 [inline] sync_rcu_exp_select_node_cpus+0x662/0xb00 kernel/rcu/tree_exp.h:446 sync_rcu_exp_select_cpus kernel/rcu/tree_exp.h:513 [inline] rcu_exp_sel_wait_wake+0x248/0x1dc0 kernel/rcu/tree_exp.h:709 kthread_worker_fn+0x502/0xb70 kernel/kthread.c:844 kthread+0x2f2/0x390 kernel/kthread.c:389 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244