rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: 1-...!: (1 GPs behind) idle=78f4/1/0x4000000000000000 softirq=15406/15406 fqs=1246 rcu: (detected by 0, t=10502 jiffies, g=11477, q=355 ncpus=2) Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 6072 Comm: sed Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:__lock_acquire+0xd30/0x2cf0 kernel/locking/lockdep.c:5245 Code: 24 10 0f 85 44 03 00 00 83 3d 3b d4 6f 0e 00 0f 84 0f 07 00 00 41 f6 45 22 10 75 2c 49 89 ae 08 0b 00 00 41 8b 86 10 0b 00 00 c0 41 89 86 10 0b 00 00 83 f8 30 0f 83 51 18 00 00 3b 05 a0 9b RSP: 0018:ffffc90000a08ab0 EFLAGS: 00000046 RAX: 0000000000000001 RBX: 00000000fe09d4ff RCX: 0000000000000000 RDX: 000000005a44979c RSI: 0000000086db7919 RDI: ffff88802fbf8000 RBP: 0ac0d5affe09d4ff R08: ffffffff89b66138 R09: ffffffff8e760320 R10: dffffc0000000000 R11: ffffed1002372856 R12: ffff88802fbf8b40 R13: ffff88802fbf8b40 R14: ffff88802fbf8000 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812556a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f0a303ce008 CR3: 0000000078ab4000 CR4: 00000000003526f0 Call Trace: lock_acquire+0xf0/0x2e0 kernel/locking/lockdep.c:5868 rcu_lock_acquire include/linux/rcupdate.h:312 [inline] rcu_read_lock include/linux/rcupdate.h:850 [inline] advance_sched+0xa14/0xc90 net/sched/sch_taprio.c:991 __run_hrtimer kernel/time/hrtimer.c:1785 [inline] __hrtimer_run_queues+0x53a/0xcc0 kernel/time/hrtimer.c:1849 hrtimer_interrupt+0x42b/0x1010 kernel/time/hrtimer.c:1911 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1045 [inline] __sysvec_apic_timer_interrupt+0x102/0x460 arch/x86/kernel/apic/apic.c:1062 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1056 [inline] sysvec_apic_timer_interrupt+0xa1/0xc0 arch/x86/kernel/apic/apic.c:1056 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:lock_is_held_type+0x106/0x150 kernel/locking/lockdep.c:5945 Code: 18 00 00 b8 ff ff ff ff 65 0f c1 05 04 c0 6d 07 83 f8 01 75 25 9c 58 a9 00 02 00 00 75 39 41 f7 c4 00 02 00 00 74 01 fb 89 d8 <5b> 41 5c 41 5d 41 5e 41 5f 5d e9 4b e3 02 00 cc 90 0f 0b 90 48 c7 RSP: 0018:ffffc9000481f288 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 0000000000000001 RCX: 0000000000000046 RDX: 0000000000000000 RSI: ffffffff8e15d4e2 RDI: ffffffff8c277400 RBP: 00000000ffffffff R08: 0000000000000003 R09: 0000000000000004 R10: dffffc0000000000 R11: fffffbfff35ea30c R12: 0000000000000246 R13: ffff88802fbf8000 R14: ffff88807911f180 R15: 0000000000000000 lock_is_held include/linux/lockdep.h:249 [inline] mt_locked lib/maple_tree.c:-1 [inline] mt_slot lib/maple_tree.c:736 [inline] mas_slot lib/maple_tree.c:769 [inline] mas_validate_parent_slot lib/maple_tree.c:6982 [inline] mt_validate+0x7a6/0x4320 lib/maple_tree.c:7172 validate_mm+0xd4/0x4c0 mm/vma.c:649 mmap_region+0x1513/0x2240 mm/vma.c:2843 do_mmap+0xc39/0x10c0 mm/mmap.c:559 vm_mmap_pgoff+0x2c9/0x4f0 mm/util.c:581 ksys_mmap_pgoff+0x51e/0x760 mm/mmap.c:605 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0a303fa242 Code: 08 00 04 00 00 eb e2 90 41 f7 c1 ff 0f 00 00 75 27 55 89 cd 53 48 89 fb 48 85 ff 74 33 41 89 ea 48 89 df b8 09 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 5e 5b 5d c3 0f 1f 00 c7 05 46 40 01 00 16 00 RSP: 002b:00007ffe811af0d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0a303fa242 RDX: 0000000000000001 RSI: 00000000000c1918 RDI: 0000000000000000 RBP: 0000000000000802 R08: 0000000000000003 R09: 0000000000000000 R10: 0000000000000802 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f0a303ce0c0 R14: 00007ffe811af4e0 R15: 00000fffd0235e1e rcu: rcu_preempt kthread starved for 8010 jiffies! g11477 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:27776 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x1585/0x5310 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 schedule_timeout+0x158/0x2c0 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x312/0x11d0 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x9e/0x2b0 kernel/rcu/tree.c:2297 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 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: 6008 Comm: syz-executor.0 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026 RIP: 0010:csd_lock_wait kernel/smp.c:342 [inline] RIP: 0010:smp_call_function_many_cond+0xcea/0x12c0 kernel/smp.c:877 Code: 89 ee 83 e6 01 31 ff e8 34 e3 0b 00 41 83 e5 01 49 bd 00 00 00 00 00 fc ff df 75 07 e8 df de 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 c3 de 0b 00 eb e4 44 RSP: 0018:ffffc9000444f440 EFLAGS: 00000293 RAX: 0000000000000000 RBX: 1ffff110170e812d RCX: ffff88807fb71e40 RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: ffffc9000444f580 R08: ffffffff90113eb7 R09: 1ffffffff20227d6 R10: dffffc0000000000 R11: fffffbfff20227d7 R12: ffff8880b8740968 R13: dffffc0000000000 R14: ffff8880b863bf80 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88812546a000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055555a4af998 CR3: 000000000e54c000 CR4: 00000000003526f0 Call Trace: on_each_cpu_cond_mask+0x3f/0x80 kernel/smp.c:1043 __flush_tlb_multi arch/x86/include/asm/paravirt.h:57 [inline] flush_tlb_multi arch/x86/mm/tlb.c:1382 [inline] flush_tlb_mm_range+0x5c3/0x10c0 arch/x86/mm/tlb.c:1472 tlb_flush arch/x86/include/asm/tlb.h:23 [inline] tlb_flush_mmu_tlbonly include/asm-generic/tlb.h:505 [inline] tlb_flush_mmu+0x1af/0xa30 mm/mmu_gather.c:403 tlb_finish_mmu+0xf9/0x230 mm/mmu_gather.c:529 free_ldt_pgtables+0x19d/0x350 arch/x86/kernel/ldt.c:411 arch_exit_mmap arch/x86/include/asm/mmu_context.h:232 [inline] exit_mmap+0x1b7/0xa00 mm/mmap.c:1287 __mmput+0x118/0x430 kernel/fork.c:1174 exit_mm+0x168/0x220 kernel/exit.c:581 do_exit+0x62e/0x2310 kernel/exit.c:959 do_group_exit+0x21b/0x2d0 kernel/exit.c:1112 get_signal+0x1284/0x1330 kernel/signal.c:3034 arch_do_signal_or_restart+0xbc/0x830 arch/x86/kernel/signal.c:337 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline] exit_to_user_mode_loop+0x86/0x480 kernel/entry/common.c:98 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:325 [inline] do_syscall_64+0x32d/0xf80 arch/x86/entry/syscall_64.c:100 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7ff42ec905d7 Code: Unable to access opcode bytes at 0x7ff42ec905ad. RSP: 002b:00007ffea85390a0 EFLAGS: 00000202 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 000055555a4a6480 RCX: 00007ff42ec905d7 RDX: 0000000040000000 RSI: 00007ffea85390fc RDI: ffffffffffffffff RBP: 00007ffea85390fc R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffea8539738 R13: 0000000000000002 R14: 00007ff42ed234c0 R15: 00000000fffffff1