rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 0-...!: (1 GPs behind) idle=ebac/1/0x4000000000000000 softirq=23191/23201 fqs=59 rcu: (detected by 1, t=10506 jiffies, g=10613, q=585 ncpus=2) Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 6440 Comm: dhcpcd-run-hook Not tainted 6.17.0-rc1-syzkaller-gdfd4b508c8c6 #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: 86 c6 55 00 48 89 df 5b e9 5d 4d 5b 00 be 03 00 00 00 5b e9 52 be 27 03 66 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1e fa 48 8b 34 24 65 48 8b 15 c8 ac 1a 12 65 8b 05 d9 ac 1a RSP: 0018:ffffc90000007e38 EFLAGS: 00000046 RAX: 0000000080010000 RBX: ffff8880b8427e80 RCX: ffffffff81a86086 RDX: ffff88804a00c880 RSI: 0000000000000000 RDI: 0000000000000001 RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: ffffffff9b0b7418 R12: ffff8880b8427c80 R13: 0000000000000000 R14: ffff888078c7d340 R15: ffffffff89a77510 FS: 00007f7eae343c80(0000) GS:ffff8881246bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f7eae5df7b8 CR3: 000000004cc81000 CR4: 00000000003526f0 Call Trace: get_current arch/x86/include/asm/current.h:25 [inline] __run_hrtimer kernel/time/hrtimer.c:1759 [inline] __hrtimer_run_queues+0x1cb/0xad0 kernel/time/hrtimer.c:1825 hrtimer_interrupt+0x397/0x8e0 kernel/time/hrtimer.c:1887 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1039 [inline] __sysvec_apic_timer_interrupt+0x10b/0x3f0 arch/x86/kernel/apic/apic.c:1056 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] sysvec_apic_timer_interrupt+0x9f/0xc0 arch/x86/kernel/apic/apic.c:1050 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:deref_stack_reg arch/x86/kernel/unwind_orc.c:403 [inline] RIP: 0010:unwind_next_frame+0xcfe/0x20a0 arch/x86/kernel/unwind_orc.c:585 Code: ff e9 a8 f6 ff ff 49 8d 76 f8 ba 08 00 00 00 4d 8d 7d 34 4c 89 ef 4c 89 44 24 28 48 89 4c 24 20 48 89 74 24 18 e8 f2 f0 ff ff <84> c0 0f 84 7c f6 ff ff 48 8b 7c 24 18 e8 d0 e8 ff ff 48 89 ee 48 RSP: 0018:ffffc90003107118 EFLAGS: 00000292 RAX: 0000000000000001 RBX: 0000000000000001 RCX: ffffc90003108000 RDX: ffffc90003107201 RSI: ffffc90003107270 RDI: ffffc900031071d8 RBP: ffffc90003107220 R08: ffffffff913fc1d8 R09: 0000000000000000 R10: ffffc900031071d8 R11: 00000000000061ee R12: ffffc90003107228 R13: ffffc900031071d8 R14: ffffc90003107278 R15: ffffc9000310720c __unwind_start+0x45f/0x7f0 arch/x86/kernel/unwind_orc.c:758 unwind_start arch/x86/include/asm/unwind.h:64 [inline] arch_stack_walk+0x73/0x100 arch/x86/kernel/stacktrace.c:24 stack_trace_save+0x8e/0xc0 kernel/stacktrace.c:122 kasan_save_stack+0x33/0x60 mm/kasan/common.c:47 kasan_save_track+0x14/0x30 mm/kasan/common.c:68 unpoison_slab_object mm/kasan/common.c:330 [inline] __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:356 kasan_slab_alloc include/linux/kasan.h:250 [inline] slab_post_alloc_hook mm/slub.c:4180 [inline] slab_alloc_node mm/slub.c:4229 [inline] kmem_cache_alloc_noprof+0x1cb/0x3b0 mm/slub.c:4236 ptlock_alloc+0x1f/0x70 mm/memory.c:7161 ptlock_init include/linux/mm.h:2953 [inline] pagetable_pte_ctor include/linux/mm.h:3002 [inline] __pte_alloc_one_noprof include/asm-generic/pgalloc.h:78 [inline] pte_alloc_one+0x82/0x3a0 arch/x86/mm/pgtable.c:18 __pte_alloc+0x6d/0x3c0 mm/memory.c:452 copy_pte_range mm/memory.c:1107 [inline] copy_pmd_range mm/memory.c:1261 [inline] copy_pud_range mm/memory.c:1298 [inline] copy_p4d_range mm/memory.c:1322 [inline] copy_page_range+0x3b83/0x5c80 mm/memory.c:1410 dup_mmap+0xe88/0x21d0 mm/mmap.c:1834 dup_mm kernel/fork.c:1485 [inline] copy_mm kernel/fork.c:1537 [inline] copy_process+0x4081/0x7690 kernel/fork.c:2175 kernel_clone+0xfc/0x930 kernel/fork.c:2605 __do_sys_clone+0xce/0x120 kernel/fork.c:2748 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f7eae4dd636 Code: 89 df e8 6d e8 f6 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 52 89 c5 85 c0 75 31 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffd74a68e70 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007ffd74a68e78 RCX: 00007f7eae4dd636 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 000055c27b0cb5e0 R08: 0000000000000000 R09: 0000000000000040 R10: 00007f7eae343f50 R11: 0000000000000246 R12: 000055c27b0d9948 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10210 jiffies! g10613 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:28936 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x1190/0x5de0 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] schedule+0xe7/0x3a0 kernel/sched/core.c:7058 schedule_timeout+0x123/0x290 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1ea/0xb00 kernel/rcu/tree.c:2083 rcu_gp_kthread+0x270/0x380 kernel/rcu/tree.c:2285 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x5d7/0x6f0 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: 1 UID: 0 PID: 6364 Comm: udevd Not tainted 6.17.0-rc1-syzkaller-gdfd4b508c8c6 #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+0xe02/0x1600 kernel/smp.c:877 Code: 10 4c 89 74 24 10 49 89 d5 48 89 d5 48 89 54 24 18 49 c1 ed 03 83 e5 07 4d 01 e5 83 c5 03 e8 05 05 0c 00 f3 90 41 0f b6 45 00 <40> 38 c5 7c 08 84 c0 0f 85 e0 05 00 00 8b 43 08 31 ff 83 e0 01 41 RSP: 0000:ffffc900036c78a8 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff8880b8442000 RCX: ffffffff81af8e61 RDX: ffff88802cfd2440 RSI: ffffffff81af8e3b RDI: 0000000000000005 RBP: 0000000000000003 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: dffffc0000000000 R13: ffffed1017088401 R14: 0000000000000001 R15: 0000000000000000 FS: 00007f1dcb3f3880(0000) GS:ffff8881247bc000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000558fe1a91fe8 CR3: 0000000076c9d000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x40/0x90 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+0x4a0/0x17a0 arch/x86/mm/tlb.c:1451 flush_tlb_page arch/x86/include/asm/tlbflush.h:324 [inline] ptep_clear_flush+0x136/0x180 mm/pgtable-generic.c:101 wp_page_copy mm/memory.c:3618 [inline] do_wp_page+0x1683/0x4f00 mm/memory.c:4013 handle_pte_fault mm/memory.c:6068 [inline] __handle_mm_fault+0x1b2d/0x2a50 mm/memory.c:6195 handle_mm_fault+0x589/0xd10 mm/memory.c:6364 do_user_addr_fault+0x60c/0x1370 arch/x86/mm/fault.c:1336 handle_page_fault arch/x86/mm/fault.c:1476 [inline] exc_page_fault+0x5c/0xb0 arch/x86/mm/fault.c:1532 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:0x7f1dcacb5db7 Code: 00 00 00 41 55 48 89 d0 49 89 fd 41 54 49 89 f4 53 4c 89 c3 48 83 ec 10 48 39 4f 60 0f 84 c1 00 00 00 42 f6 44 01 08 01 74 59 <48> 83 61 08 fe 48 3d ff 03 00 00 76 69 49 8b 55 70 49 8d 75 60 48 RSP: 002b:00007ffe2e46d130 EFLAGS: 00010202 RAX: 0000000000006010 RBX: 00000000000001f0 RCX: 0000558fe1a91fe0 RDX: 0000000000006010 RSI: 0000558fe1a8bfd0 RDI: 00007f1dcadf1ac0 RBP: 00007f1dcadf1ac0 R08: 00000000000001f0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 0000558fe1a8bfd0 R13: 00007f1dcadf1ac0 R14: 00000000000001f0 R15: 00007f1dcadf1ac0