rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=21b4/1/0x4000000000000000 softirq=167177/167184 fqs=15 rcu: (detected by 0, t=10506 jiffies, g=144333, q=422 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 30022 Comm: syz.0.8654 Not tainted 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:__sanitizer_cov_trace_pc+0x0/0x70 kernel/kcov.c:210 Code: 89 fb e8 23 00 00 00 48 8b 3d 64 49 fe 0b 48 89 de 5b e9 73 98 58 00 cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 04 24 65 48 8b 0c 25 08 40 a0 92 65 8b 15 88 94 RSP: 0018:ffffc90000a08d00 EFLAGS: 00000097 RAX: ffffffff81ade26f RBX: ffff88807f10a340 RCX: 0000000000010000 RDX: ffff88804d893c00 RSI: 0000000000000001 RDI: 0000000000000007 RBP: 0000000000000000 R08: ffffffff99d91223 R09: 1ffffffff33b2244 R10: dffffc0000000000 R11: fffffbfff33b2245 R12: dffffc0000000000 R13: dffffc0000000000 R14: ffff8880b8727c80 R15: 0000000000000001 FS: 00007f515a28e6c0(0000) GS:ffff888125d1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f514f07fc00 CR3: 00000000600a2000 CR4: 0000000000350ef0 Call Trace: cpu_max_bits_warn include/linux/cpumask.h:135 [inline] cpumask_check include/linux/cpumask.h:142 [inline] cpumask_test_cpu include/linux/cpumask.h:646 [inline] cpu_online include/linux/cpumask.h:1205 [inline] trace_hrtimer_start include/trace/events/timer.h:222 [inline] debug_activate kernel/time/hrtimer.c:485 [inline] enqueue_hrtimer+0x5e/0x3a0 kernel/time/hrtimer.c:1088 __run_hrtimer kernel/time/hrtimer.c:1778 [inline] __hrtimer_run_queues+0x656/0xc60 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x45b/0xaa0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x410 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:folios_put_refs+0x438/0x640 mm/swap.c:952 Code: 21 00 4c 8b 6c 24 10 48 8b 44 24 30 0f b6 04 18 84 c0 75 3e 41 0f b6 04 24 49 39 c7 0f 83 9c 00 00 00 e8 3b ae c4 ff 49 ff c7 <48> 83 44 24 28 04 49 83 c5 08 e9 b7 fc ff ff e8 24 ae c4 ff 48 c7 RSP: 0018:ffffc9000bb1f5a0 EFLAGS: 00000207 RAX: ffffffff81fafd55 RBX: dffffc0000000000 RCX: 0000000000080000 RDX: ffffc9000d6cf000 RSI: 000000000000e51e RDI: 000000000000e51f RBP: ffffc9000bb1f690 R08: ffffea0000f44c77 R09: 1ffffd40001e898e R10: dffffc0000000000 R11: fffff940001e898f R12: ffff8880b8732fe8 R13: ffff8880b8732ff8 R14: 0000000000000001 R15: 0000000000000003 folios_put include/linux/mm.h:1419 [inline] folio_batch_move_lru+0x319/0x3a0 mm/swap.c:175 __folio_batch_add_and_move+0x5ad/0xd20 mm/swap.c:196 shmem_alloc_and_add_folio+0xcb3/0xf60 mm/shmem.c:2006 shmem_get_folio_gfp+0x59d/0x1660 mm/shmem.c:2597 shmem_get_folio mm/shmem.c:2703 [inline] shmem_write_begin+0xf7/0x2b0 mm/shmem.c:3353 generic_perform_write+0x2c5/0x900 mm/filemap.c:4175 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3528 new_sync_write fs/read_write.c:593 [inline] vfs_write+0x5c9/0xb30 fs/read_write.c:686 ksys_write+0x145/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f515938d69f Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 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 4c 93 02 00 48 RSP: 002b:00007f515a28ddf0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000080000 RCX: 00007f515938d69f RDX: 0000000000080000 RSI: 00007f514f000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000000 R09: 00000000000005ea R10: 00000000000007d8 R11: 0000000000000293 R12: 0000000000000003 R13: 00007f515a28def0 R14: 00007f515a28deb0 R15: 00007f514f000000 rcu: rcu_preempt kthread starved for 10430 jiffies! g144333 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:27416 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1798/0x4cc0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0x165/0x360 kernel/sched/core.c:7058 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2285 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 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: 29997 Comm: syz.3.8643 Not tainted 6.17.0-rc1-syzkaller-00038-g0cc53520e68b #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xd38/0x12d0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 b6 62 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 61 5e 0b 00 eb 38 f3 90 42 0f b6 04 2b <84> c0 75 11 41 f7 04 24 01 00 00 00 74 1e e8 45 5e 0b 00 eb e4 44 RSP: 0018:ffffc9000bb0f560 EFLAGS: 00000246 RAX: 0000000000000000 RBX: 1ffff110170e7f61 RCX: 0000000000080000 RDX: ffffc90010217000 RSI: 000000000007ffff RDI: 0000000000080000 RBP: ffffc9000bb0f6e0 R08: ffffffff8fa37e37 R09: 1ffffffff1f46fc6 R10: dffffc0000000000 R11: fffffbfff1f46fc7 R12: ffff8880b873fb08 R13: dffffc0000000000 R14: ffff8880b863b1c0 R15: 0000000000000001 FS: 00007f58af37f6c0(0000) GS:ffff888125c1c000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b2ef1fff8 CR3: 0000000056835000 CR4: 0000000000350ef0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1044 __flush_tlb_multi arch/x86/include/asm/paravirt.h:91 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1361 [inline] flush_tlb_mm_range+0x6b1/0x12d0 arch/x86/mm/tlb.c:1451 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:490 [inline] tlb_flush_mmu+0x1a7/0x680 mm/mmu_gather.c:403 tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497 vms_clear_ptes+0x42c/0x540 mm/vma.c:1235 vms_complete_munmap_vmas+0x206/0x8a0 mm/vma.c:1277 do_vmi_align_munmap+0x358/0x420 mm/vma.c:1536 do_vmi_munmap+0x253/0x2e0 mm/vma.c:1584 __vm_munmap+0x23b/0x3d0 mm/vma.c:3155 __do_sys_munmap mm/mmap.c:1080 [inline] __se_sys_munmap mm/mmap.c:1077 [inline] __x64_sys_munmap+0x60/0x70 mm/mmap.c:1077 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f58ae58ec77 Code: 00 00 00 48 c7 c2 a8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f58af37ee18 EFLAGS: 00000246 ORIG_RAX: 000000000000000b RAX: ffffffffffffffda RBX: 0000000002000000 RCX: 00007f58ae58ec77 RDX: 0000000000000000 RSI: 0000000008400000 RDI: 00007f58a4200000 RBP: 0000000000000000 R08: 0000000000000000 R09: 000000000000b954 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000003 R13: 00007f58af37eef0 R14: 00007f58af37eeb0 R15: 00007f58a4200000