rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=6694/1/0x4000000000000000 softirq=90347/90351 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P16981/1:b..l rcu: (detected by 0, t=10505 jiffies, g=97529, q=458 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 17520 Comm: syz.7.4324 Tainted: G L syzkaller #0 PREEMPT(lazy) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:__hrtimer_run_queues+0x554/0xa10 kernel/time/hrtimer.c:2108 Code: 00 00 48 8b 84 24 80 00 00 00 42 80 3c 28 00 74 08 4c 89 f7 e8 ed 3b 83 00 49 8b 2e 48 85 ed 0f 84 1c 04 00 00 e8 1c 92 13 00 43 fc ff ff e8 12 92 13 00 90 0f 0b 90 e9 83 fd ff ff e8 04 92 RSP: 0018:ffffc90000a08dc0 EFLAGS: 00000002 RAX: ffffffff81b39844 RBX: ffff8880b8728310 RCX: ffff888046cc5dc0 RDX: 8000000001000001 RSI: 0000000001000001 RDI: ffff888046949300 RBP: ffff888046949300 R08: ffff888046949317 R09: ffff888046949308 R10: dffffc0000000000 R11: ffffed1008d29263 R12: ffff8880b8728180 R13: dffffc0000000000 R14: ffff8880b8728320 R15: 1ffff110170e5062 FS: 00007fca29b416c0(0000) GS:ffff888124dfd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe558330c8 CR3: 000000005514e000 CR4: 0000000000350ef0 Call Trace: hrtimer_interrupt+0x4cd/0xaa0 kernel/time/hrtimer.c:2243 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1051 [inline] __sysvec_apic_timer_interrupt+0x102/0x430 arch/x86/kernel/apic/apic.c:1068 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:get_current arch/x86/include/asm/current.h:25 [inline] RIP: 0010:write_comp_data kernel/kcov.c:245 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x8/0xb0 kernel/kcov.c:314 Code: e9 c8 11 49 ff cc 66 66 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 48 8b 04 24 <65> 48 8b 0d 98 00 cb 11 65 48 8b 15 98 00 cb 11 f7 c2 00 01 00 ff RSP: 0018:ffffc9000d17fbc8 EFLAGS: 00000246 RAX: ffffffff8263a2b1 RBX: 0000000000000001 RCX: ffff888046cc5dc0 RDX: ffffc9001ef3b000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff8263a0b1 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff8ed5a360 R12: ffff888046949328 R13: dffffc0000000000 R14: ffffffff8263a0b1 R15: ffffffff8eeff1c0 rcu_read_unlock include/linux/rcupdate.h:869 [inline] timerfd_clock_was_set+0x231/0x2c0 fs/timerfd.c:117 clock_was_set+0x80c/0x8a0 kernel/time/hrtimer.c:1007 do_settimeofday64+0x337/0x5b0 kernel/time/timekeeping.c:1730 __do_sys_clock_settime kernel/time/posix-timers.c:1139 [inline] __se_sys_clock_settime kernel/time/posix-timers.c:1123 [inline] __x64_sys_clock_settime+0x253/0x2a0 kernel/time/posix-timers.c:1123 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fca28b9e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fca29b41028 EFLAGS: 00000246 ORIG_RAX: 00000000000000e3 RAX: ffffffffffffffda RBX: 00007fca28e25fa0 RCX: 00007fca28b9e0d9 RDX: 0000000000000000 RSI: 0000200000000240 RDI: 0000000000000000 RBP: 00007fca28c35024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fca28e26038 R14: 00007fca28e25fa0 R15: 00007fff767da078 task:syz.8.4090 state:R running task stack:20240 pid:16981 tgid:16981 ppid:11344 task_flags:0x400640 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17d4/0x5820 kernel/sched/core.c:7270 preempt_schedule_irq+0x4b/0x90 kernel/sched/core.c:7592 irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:539 [inline] irqentry_exit+0x14f/0x910 kernel/entry/common.c:167 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:lock_release+0x2d7/0x3c0 kernel/locking/lockdep.c:5911 Code: 9d ef 11 00 00 00 00 eb b5 e8 65 ad 3b 0a f7 c3 00 02 00 00 74 b9 65 48 8b 05 bd 58 ef 11 48 3b 44 24 28 75 44 fb 48 83 c4 30 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 85 69 6d ff cc 48 8d 3d e2 e0 d9 RSP: 0018:ffffc90005045fc8 EFLAGS: 00000282 RAX: 1aeba2b723180500 RBX: 0000000000000206 RCX: 0000000000000046 RDX: 0000000000000002 RSI: ffffffff8e6ee26e RDI: ffffffff8c6d1880 RBP: ffff8880278fca78 R08: ffffc900050468d8 R09: ffffc900050460f8 R10: dffffc0000000000 R11: fffff52000a08c21 R12: 0000000000000002 R13: 0000000000000002 R14: ffffffff8ed5a360 R15: ffff8880278fbe80 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:871 [inline] class_rcu_destructor include/linux/rcupdate.h:1183 [inline] unwind_next_frame+0x1baa/0x2550 arch/x86/kernel/unwind_orc.c:709 arch_stack_walk+0x11b/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0xa9/0x100 kernel/stacktrace.c:122 save_stack+0x122/0x230 mm/page_owner.c:183 __set_page_owner+0x8d/0x4c0 mm/page_owner.c:359 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871 prep_new_page mm/page_alloc.c:1879 [inline] get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943 __alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436 alloc_pages_mpol+0x21e/0x390 mm/mempolicy.c:2495 folio_alloc_mpol_noprof+0x39/0x160 mm/mempolicy.c:2514 shmem_alloc_folio mm/shmem.c:1922 [inline] shmem_alloc_and_add_folio+0x43e/0xf60 mm/shmem.c:1964 shmem_get_folio_gfp+0x5da/0x16d0 mm/shmem.c:2517 shmem_get_folio mm/shmem.c:2623 [inline] shmem_write_begin+0x16c/0x330 mm/shmem.c:3254 generic_perform_write+0x2d5/0x8f0 mm/filemap.c:4374 shmem_file_write_iter+0xf8/0x120 mm/shmem.c:3429 __kernel_write_iter+0x44a/0x8f0 fs/read_write.c:621 dump_emit_page fs/coredump.c:1293 [inline] dump_user_range+0xc19/0x12c0 fs/coredump.c:1367 elf_core_dump+0x3485/0x3a90 fs/binfmt_elf.c:2106 coredump_write+0x1290/0x1960 fs/coredump.c:1047 do_coredump fs/coredump.c:1126 [inline] vfs_coredump+0x3766/0x4530 fs/coredump.c:1195 get_signal+0x1094/0x12c0 kernel/signal.c:3031 arch_do_signal_or_restart+0xbb/0x860 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:66 [inline] exit_to_user_mode_loop kernel/entry/common.c:101 [inline] __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:244 [inline] irqentry_exit_to_user_mode include/linux/irq-entry-common.h:315 [inline] irqentry_exit+0x2ba/0x910 kernel/entry/common.c:165 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:595 RIP: 0033:0x7f6008e53bd7 RSP: 002b:00007f6009ec7120 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 000000000000000b RCX: 00007f6008f9e0d9 RDX: 00007f6009ec7140 RSI: 00007f6009ec7270 RDI: 000000000000000b RBP: 00007f6009035024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000000 R13: 00007f6009226038 R14: 00007f6009225fa0 R15: 00007ffd6d361728 rcu: rcu_preempt kthread starved for 10505 jiffies! g97529 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:26848 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5520 [inline] __schedule+0x17d4/0x5820 kernel/sched/core.c:7270 __schedule_loop kernel/sched/core.c:7347 [inline] schedule+0x164/0x2b0 kernel/sched/core.c:7362 schedule_timeout+0x152/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x30c/0x11f0 kernel/rcu/tree.c:2123 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2325 kthread+0x38b/0x480 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: 0 UID: 0 PID: 15043 Comm: syz-executor Tainted: G L syzkaller #0 PREEMPT(lazy) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/16/2026 RIP: 0010:native_pause arch/x86/include/asm/vdso/processor.h:13 [inline] RIP: 0010:cpu_relax arch/x86/include/asm/vdso/processor.h:18 [inline] RIP: 0010:csd_lock_wait kernel/smp.c:363 [inline] RIP: 0010:csd_lock kernel/smp.c:396 [inline] RIP: 0010:smp_call_function_many_cond+0x61c/0x1500 kernel/smp.c:944 Code: 41 0f b6 04 04 84 c0 0f 85 d5 03 00 00 44 8b 3b 44 89 fe 83 e6 01 31 ff e8 71 4f 0c 00 41 83 e7 01 75 07 e8 66 4a 0c 00 eb 3f 90 48 b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 0f f7 RSP: 0018:ffffc9000669f420 EFLAGS: 00000293 RAX: ffffffff81bae01e RBX: ffff8880b8740e48 RCX: ffff88802efb3e80 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000669f570 R08: ffff88802efb5417 R09: 1ffff11005df6a82 R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff110170e81c9 R13: 0000000000000001 R14: ffff8880b8740e40 R15: 0000000000000001 FS: 0000555568b8e500(0000) GS:ffff888124cfd000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0595bb5d58 CR3: 0000000046be9000 CR4: 0000000000350ef0 Call Trace: __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+0x8ff/0x1090 arch/x86/mm/tlb.c:1435 dup_mmap+0x1758/0x1dc0 mm/mmap.c:1884 dup_mm kernel/fork.c:1543 [inline] copy_mm+0x11a/0x480 kernel/fork.c:1595 copy_process+0x1e75/0x43e0 kernel/fork.c:2307 kernel_clone+0x2d7/0x940 kernel/fork.c:2766 __do_sys_clone kernel/fork.c:2908 [inline] __se_sys_clone kernel/fork.c:2892 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2892 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fa92afc6b52 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:00007fffa4aee960 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007fffa4aee960 RCX: 00007fa92afc6b52 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007fffa4aeeaec R08: 0000000000000000 R09: 0000000000000001 R10: 0000555568b8e7d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 000000000008216c R15: 00007fffa4aeeb40