rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (6 ticks this GP) idle=37fc/1/0x4000000000000000 softirq=136127/136131 fqs=5 rcu: (detected by 0, t=10502 jiffies, g=201833, q=143 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 7595 Comm: syz-executor.2 Not tainted 6.5.0-rc3-syzkaller-00225-gf837f0a3c948 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 RIP: 0010:preempt_count_sub+0x64/0x150 kernel/sched/core.c:5892 Code: 10 85 c9 75 1b 65 8b 05 42 07 ab 7e 89 c2 81 e2 ff ff ff 7f 39 da 7c 13 81 fb fe 00 00 00 76 63 f7 db 65 01 1d 25 07 ab 7e 5b e8 a6 b4 c2 02 85 c0 74 f5 48 c7 c0 4c 03 ab 8e 48 ba 00 00 00 RSP: 0018:ffffc900003e8d20 EFLAGS: 00000093 RAX: 0000000080010002 RBX: ffffffff923a6618 RCX: 0000000000000000 RDX: 0000000000010002 RSI: 0000000000000004 RDI: 0000000000000001 RBP: 0000000000000006 R08: 0000000000000000 R09: fffffbfff2474cc3 R10: ffffffff923a661b R11: ffffc900003e8ff8 R12: 0000000000000001 R13: 1ffff9200007d1ac R14: ffffffff8a6ee4e0 R15: ffff888035296340 FS: 00007f74c731c6c0(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9db6f75198 CR3: 0000000073bd7000 CR4: 00000000003506e0 DR0: 00000000ffff070c DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline] _raw_spin_unlock_irqrestore+0x3b/0x70 kernel/locking/spinlock.c:194 debug_object_deactivate lib/debugobjects.c:805 [inline] debug_object_deactivate+0x28b/0x320 lib/debugobjects.c:771 debug_hrtimer_deactivate kernel/time/hrtimer.c:427 [inline] debug_deactivate kernel/time/hrtimer.c:483 [inline] __run_hrtimer kernel/time/hrtimer.c:1656 [inline] __hrtimer_run_queues+0x470/0xc10 kernel/time/hrtimer.c:1752 hrtimer_interrupt+0x31b/0x800 kernel/time/hrtimer.c:1814 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1098 [inline] __sysvec_apic_timer_interrupt+0x14a/0x430 arch/x86/kernel/apic/apic.c:1115 sysvec_apic_timer_interrupt+0x8e/0xc0 arch/x86/kernel/apic/apic.c:1109 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:645 RIP: 0010:lock_acquire+0x1ef/0x510 kernel/locking/lockdep.c:5729 Code: c1 05 f5 e7 9b 7e 83 f8 01 0f 85 b0 02 00 00 9c 58 f6 c4 02 0f 85 9b 02 00 00 48 85 ed 74 01 fb 48 b8 00 00 00 00 00 fc ff df <48> 01 c3 48 c7 03 00 00 00 00 48 c7 43 08 00 00 00 00 48 8b 84 24 RSP: 0018:ffffc900037af0d8 EFLAGS: 00000206 RAX: dffffc0000000000 RBX: 1ffff920006f5e1d RCX: 0000000000000001 RDX: 1ffff11006183178 RSI: ffffffff8a6c6ca0 RDI: ffffffff8ac7e6a0 RBP: 0000000000000200 R08: 0000000000000000 R09: fffffbfff23081d0 R10: ffffffff91840e87 R11: 000000000000c2de R12: 0000000000000000 R13: 0000000000000000 R14: ffffffff8c9a3340 R15: 0000000000000000 rcu_lock_acquire include/linux/rcupdate.h:303 [inline] rcu_read_lock include/linux/rcupdate.h:749 [inline] page_ext_get+0x3c/0x310 mm/page_ext.c:167 __page_table_check_zero+0x139/0x5e0 mm/page_table_check.c:142 prep_new_page mm/page_alloc.c:1577 [inline] get_page_from_freelist+0x10a9/0x31e0 mm/page_alloc.c:3221 __alloc_pages+0x1d0/0x4a0 mm/page_alloc.c:4477 __folio_alloc+0x16/0x40 mm/page_alloc.c:4509 vma_alloc_folio+0x156/0x890 mm/mempolicy.c:2253 shmem_alloc_folio+0xb5/0x170 mm/shmem.c:1579 shmem_alloc_and_acct_folio+0x168/0x5e0 mm/shmem.c:1603 shmem_get_folio_gfp+0xce7/0x1b60 mm/shmem.c:1948 shmem_fault+0x1db/0x890 mm/shmem.c:2163 __do_fault+0x107/0x5f0 mm/memory.c:4198 do_read_fault mm/memory.c:4547 [inline] do_fault mm/memory.c:4670 [inline] do_pte_missing mm/memory.c:3664 [inline] handle_pte_fault mm/memory.c:4939 [inline] __handle_mm_fault+0x27e0/0x3b80 mm/memory.c:5079 handle_mm_fault+0x2ab/0x9d0 mm/memory.c:5233 faultin_page mm/gup.c:959 [inline] __get_user_pages+0x5c1/0x1010 mm/gup.c:1258 populate_vma_page_range+0x2d4/0x410 mm/gup.c:1649 __mm_populate+0x1d7/0x380 mm/gup.c:1758 mm_populate include/linux/mm.h:3196 [inline] vm_mmap_pgoff+0x2c9/0x3b0 mm/util.c:548 ksys_mmap_pgoff+0x7d/0x5b0 mm/mmap.c:1408 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x38/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f74c667cb29 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f74c731c0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007f74c679bf80 RCX: 00007f74c667cb29 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000000020000000 RBP: 00007f74c66c847a R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f74c679bf80 R15: 00007fff013f9198 rcu: rcu_preempt kthread starved for 10492 jiffies! g201833 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:27808 pid:15 ppid:2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5381 [inline] __schedule+0xee1/0x59f0 kernel/sched/core.c:6710 schedule+0xe7/0x1b0 kernel/sched/core.c:6786 schedule_timeout+0x157/0x2c0 kernel/time/timer.c:2167 rcu_gp_fqs_loop+0x1ec/0xa50 kernel/rcu/tree.c:1609 rcu_gp_kthread+0x249/0x380 kernel/rcu/tree.c:1808 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:296 RIP: 0000:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0000:0000000000000000 EFLAGS: 00000000 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: Stack dump where RCU GP kthread last ran: CPU: 0 PID: 32541 Comm: kworker/u4:8 Not tainted 6.5.0-rc3-syzkaller-00225-gf837f0a3c948 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023 Workqueue: events_unbound toggle_allocation_gate RIP: 0010:csd_lock_wait kernel/smp.c:296 [inline] RIP: 0010:smp_call_function_many_cond+0x4d6/0x1570 kernel/smp.c:835 Code: 0b 00 85 ed 74 4d 48 b8 00 00 00 00 00 fc ff df 4d 89 fc 4c 89 fd 49 c1 ec 03 83 e5 07 49 01 c4 83 c5 03 e8 dc 5e 0b 00 f3 90 <41> 0f b6 04 24 40 38 c5 7c 08 84 c0 0f 85 3c 0e 00 00 8b 43 08 31 RSP: 0018:ffffc9000341f938 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b9941860 RCX: 0000000000000000 RDX: ffff8880332f21c0 RSI: ffffffff817a2a94 RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffed101732830d R13: 0000000000000001 R14: ffff8880b983d5c0 R15: ffff8880b9941868 FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffffffffd6 CR3: 000000000c776000 CR4: 00000000003506f0 DR0: 00000000ffff070c DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: on_each_cpu_cond_mask+0x40/0x90 kernel/smp.c:1003 on_each_cpu include/linux/smp.h:71 [inline] text_poke_sync arch/x86/kernel/alternative.c:2001 [inline] text_poke_bp_batch+0x250/0x780 arch/x86/kernel/alternative.c:2211 text_poke_flush arch/x86/kernel/alternative.c:2402 [inline] text_poke_flush arch/x86/kernel/alternative.c:2399 [inline] text_poke_finish+0x1a/0x30 arch/x86/kernel/alternative.c:2409 arch_jump_label_transform_apply+0x17/0x30 arch/x86/kernel/jump_label.c:146 jump_label_update+0x32e/0x410 kernel/jump_label.c:829 static_key_enable_cpuslocked+0x1b5/0x270 kernel/jump_label.c:205 static_key_enable+0x1a/0x20 kernel/jump_label.c:218 toggle_allocation_gate mm/kfence/core.c:831 [inline] toggle_allocation_gate+0xf4/0x250 mm/kfence/core.c:823 process_one_work+0xaa2/0x16f0 kernel/workqueue.c:2597 worker_thread+0x687/0x1110 kernel/workqueue.c:2748 kthread+0x33a/0x430 kernel/kthread.c:389 ret_from_fork+0x2c/0x70 arch/x86/kernel/process.c:145 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:296 RIP: 0000:0x0 Code: Unable to access opcode bytes at 0xffffffffffffffd6. RSP: 0000:0000000000000000 EFLAGS: 00000000 ORIG_RAX: 0000000000000000 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000