rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 ticks this GP) idle=f744/1/0x4000000000000000 softirq=74939/74939 fqs=0 rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P13631/2:b..l rcu: (detected by 1, t=10502 jiffies, g=60557, q=233 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 13654 Comm: dhcpcd-run-hook Not tainted 6.16.0-rc3-syzkaller-00116-ge34a79b96ab9 #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025 RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:27 [inline] RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp4+0x11/0x90 kernel/kcov.c:314 Code: 09 cc 0f 1f 80 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 14 25 08 d0 99 92 <65> 8b 0d 68 7e d9 10 81 e1 00 01 ff 00 74 11 81 f9 00 01 00 00 75 RSP: 0018:ffffc90000007d38 EFLAGS: 00000046 RAX: ffffffff81ae5d3e RBX: 0000000000000001 RCX: ffff888025363c00 RDX: ffff888025363c00 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc90000007e90 R08: ffff888026935357 R09: 0000000000000000 R10: ffff888026935348 R11: ffffed1004d26a6b R12: ffff888026935340 R13: dffffc0000000000 R14: 185521e8b54878a8 R15: ffff8880b8627bc0 FS: 0000000000000000(0000) GS:ffff888125c83000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 000000007a28c000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __run_hrtimer kernel/time/hrtimer.c:1727 [inline] __hrtimer_run_queues+0x26e/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:rcu_preempt_read_enter kernel/rcu/tree_plugin.h:391 [inline] RIP: 0010:__rcu_read_lock+0x15/0x60 kernel/rcu/tree_plugin.h:414 Code: 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 53 65 48 8b 1c 25 08 d0 99 92 48 81 c3 44 04 00 00 <48> 89 d8 48 c1 e8 03 48 b9 00 00 00 00 00 fc ff df 0f b6 04 08 84 RSP: 0018:ffffc90002e973a8 EFLAGS: 00000286 RAX: 0000000000000001 RBX: ffff888025364044 RCX: 948e7d1a5dfadc00 RDX: dffffc0000000000 RSI: ffffffff81ace55c RDI: ffffc90002e97488 RBP: dffffc0000000000 R08: ffffc90002e97550 R09: 0000000000000000 R10: ffffc90002e974d8 R11: ffffffff81ace5b0 R12: 1ffff920005d2e91 R13: ffffc90002e974c0 R14: ffffc90002e97488 R15: ffffc90002e97520 rcu_read_lock include/linux/rcupdate.h:839 [inline] class_rcu_constructor include/linux/rcupdate.h:1155 [inline] unwind_next_frame+0x9e/0x2390 arch/x86/kernel/unwind_orc.c:479 arch_stack_walk+0x11c/0x150 arch/x86/kernel/stacktrace.c:25 stack_trace_save+0x9c/0xe0 kernel/stacktrace.c:122 kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x3e/0x80 mm/kasan/common.c:68 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576 poison_slab_object mm/kasan/common.c:247 [inline] __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264 kasan_slab_free include/linux/kasan.h:233 [inline] slab_free_hook mm/slub.c:2381 [inline] slab_free mm/slub.c:4643 [inline] kmem_cache_free+0x18f/0x400 mm/slub.c:4745 anon_vma_chain_free mm/rmap.c:147 [inline] unlink_anon_vmas+0x614/0x670 mm/rmap.c:447 free_pgtables+0x7bf/0xaf0 mm/memory.c:402 exit_mmap+0x444/0xb50 mm/mmap.c:1295 __mmput+0x118/0x420 kernel/fork.c:1121 exit_mm+0x1da/0x2c0 kernel/exit.c:581 do_exit+0x648/0x22e0 kernel/exit.c:952 do_group_exit+0x21c/0x2d0 kernel/exit.c:1105 __do_sys_exit_group kernel/exit.c:1116 [inline] __se_sys_exit_group kernel/exit.c:1114 [inline] __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1114 x64_sys_call+0x21ba/0x21c0 arch/x86/include/generated/asm/syscalls_64.h:232 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: 0033:0x7f1ed2a716c5 Code: Unable to access opcode bytes at 0x7f1ed2a7169b. RSP: 002b:00007ffe1e07c538 EFLAGS: 00000202 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 00007ffe1e07c804 RCX: 00007f1ed2a716c5 RDX: 00000000000000e7 RSI: ffffffffffffff88 RDI: 0000000000000000 RBP: 0000000000000003 R08: 00007ffe1e07c630 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000202 R12: 0000000000000000 R13: 00007ffe1e07c870 R14: 00007f1ed2c81000 R15: 0000565182d8dd98 task:syz.2.1705 state:R running task stack:25264 pid:13631 tgid:13628 ppid:8644 task_flags:0x400140 flags:0x00004002 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785 preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7108 irqentry_exit+0x6f/0x90 kernel/entry/common.c:307 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:check_kcov_mode kernel/kcov.c:183 [inline] RIP: 0010:write_comp_data kernel/kcov.c:246 [inline] RIP: 0010:__sanitizer_cov_trace_const_cmp8+0x18/0x90 kernel/kcov.c:321 Code: 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 0c 25 08 d0 99 92 65 8b 15 c8 7d d9 10 <81> e2 00 01 ff 00 74 11 81 fa 00 01 00 00 75 57 83 b9 3c 16 00 00 RSP: 0018:ffffc9000b1cf470 EFLAGS: 00000202 RAX: ffffffff8b5d7ab3 RBX: ffff888025f01080 RCX: ffff888034a00000 RDX: 0000000080000000 RSI: 0000000000000002 RDI: 0000000000000002 RBP: ffff888025f01080 R08: ffff888034a00000 R09: 0000000000000002 R10: 0000000000000003 R11: 0000000000000000 R12: ffffc9000b1cf712 R13: dffffc0000000000 R14: ffff88804e0d6ec2 R15: 0000000000000002 xa_is_internal include/linux/xarray.h:175 [inline] xa_is_node include/linux/xarray.h:1270 [inline] xas_load+0x93/0x5b0 lib/xarray.c:241 xas_find+0x157/0x990 lib/xarray.c:1406 next_uptodate_folio+0x32/0x5d0 mm/filemap.c:3562 filemap_map_pages+0x21f/0x1740 mm/filemap.c:3714 do_fault_around mm/memory.c:5548 [inline] do_read_fault mm/memory.c:5581 [inline] do_fault mm/memory.c:5724 [inline] do_pte_missing mm/memory.c:4251 [inline] handle_pte_fault mm/memory.c:6069 [inline] __handle_mm_fault+0x3687/0x5620 mm/memory.c:6212 handle_mm_fault+0x2d5/0x7f0 mm/memory.c:6381 faultin_page mm/gup.c:1186 [inline] __get_user_pages+0x1af4/0x30b0 mm/gup.c:1488 populate_vma_page_range+0x26b/0x340 mm/gup.c:1926 __mm_populate+0x24c/0x380 mm/gup.c:2029 mm_populate include/linux/mm.h:3348 [inline] vm_mmap_pgoff+0x3f0/0x4c0 mm/util.c:584 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: 0033:0x7fda1078e929 RSP: 002b:00007fda11515038 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 00007fda109b6080 RCX: 00007fda1078e929 RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000200000000000 RBP: 00007fda10810b39 R08: ffffffffffffffff R09: 0000000000000000 R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007fda109b6080 R15: 00007ffc21faf3c8 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g60557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=64981 rcu: rcu_preempt kthread starved for 10502 jiffies! g60557 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 ->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:I stack:27128 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5396 [inline] __schedule+0x16a2/0x4cb0 kernel/sched/core.c:6785 __schedule_loop kernel/sched/core.c:6863 [inline] schedule+0x165/0x360 kernel/sched/core.c:6878 schedule_timeout+0x12b/0x270 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x301/0x1540 kernel/rcu/tree.c:2054 rcu_gp_kthread+0x99/0x390 kernel/rcu/tree.c:2256 kthread+0x70e/0x8a0 kernel/kthread.c:464 ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245