rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P12889/3:b..l rcu: (detected by 1, t=10502 jiffies, g=69165, q=570 ncpus=2) task:sed state:R running task stack:26280 pid:12889 tgid:12889 ppid:12888 task_flags:0x400000 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7513 irqentry_exit_to_kernel_mode_preempt include/linux/irq-entry-common.h:476 [inline] irqentry_exit_to_kernel_mode include/linux/irq-entry-common.h:547 [inline] irqentry_exit+0x205/0x7e0 kernel/entry/common.c:164 asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:trace_lock_release include/trace/events/lock.h:69 [inline] RIP: 0010:lock_release+0x240/0x310 kernel/locking/lockdep.c:5879 Code: fe ff 48 c7 c0 00 32 87 8e 48 85 c0 0f 84 00 fe ff ff be 04 00 00 00 48 89 c7 e8 8b ab 07 00 65 49 ff 44 24 08 e9 e8 fd ff ff 3b 5e 08 00 84 c0 0f 85 f9 fd ff ff 48 8d 3d 3c 8b f6 0e 67 48 RSP: 0000:ffffc9000482fa20 EFLAGS: 00000297 RAX: 0000000000000001 RBX: ffffffff8e7e54e0 RCX: ffffffff8244c6a4 RDX: ffff8880276e4a00 RSI: ffffffff8244c0d7 RDI: ffffffff8e7e54e0 RBP: ffffffff8244c0d7 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc9000482fdb8 R13: 0000000000000000 R14: ffff888074e13dc0 R15: ffffc9000482fd58 rcu_lock_release include/linux/rcupdate.h:310 [inline] rcu_read_unlock include/linux/rcupdate.h:869 [inline] pte_unmap include/linux/pgtable.h:117 [inline] filemap_map_pages+0x15dc/0x2140 mm/filemap.c:3942 do_fault_around mm/memory.c:5851 [inline] do_read_fault mm/memory.c:5884 [inline] do_fault+0x985/0x1750 mm/memory.c:6027 do_pte_missing mm/memory.c:4550 [inline] handle_pte_fault mm/memory.c:6411 [inline] __handle_mm_fault+0x187d/0x2a00 mm/memory.c:6549 handle_mm_fault+0x36d/0xa20 mm/memory.c:6718 do_user_addr_fault+0x5a3/0x12f0 arch/x86/mm/fault.c:1334 handle_page_fault arch/x86/mm/fault.c:1474 [inline] exc_page_fault+0x6f/0xd0 arch/x86/mm/fault.c:1527 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618 RIP: 0033:0x7f3a5ff4e8f4 RSP: 002b:00007ffe05a3dc48 EFLAGS: 00010287 RAX: 00007f3a5fe7c190 RBX: 00007f3a5fe7c190 RCX: 0000000000000009 RDX: 00007f3a5ff394e8 RSI: 00007f3a5ff3e0c0 RDI: ffff80c5a00c6b24 RBP: 00007ffe05a3dda0 R08: 0000000000000030 R09: 00000000effffef5 R10: 0000000070000029 R11: 00007ffe05a3de88 R12: 0000000000000003 R13: 00007f3a5ff3e0c0 R14: 00007ffe05a3de40 R15: 00007f3a5ff3d918 rcu: rcu_preempt kthread starved for 10498 jiffies! g69165 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:28904 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5388 [inline] __schedule+0x1295/0x67a0 kernel/sched/core.c:7189 __schedule_loop kernel/sched/core.c:7268 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7283 schedule_timeout+0x127/0x280 kernel/time/sleep_timeout.c:99 rcu_gp_fqs_loop+0x1a9/0x900 kernel/rcu/tree.c:2095 rcu_gp_kthread+0x179/0x230 kernel/rcu/tree.c:2297 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 12886 Comm: syz.6.1162 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026 RIP: 0010:rb_red_parent lib/rbtree.c:66 [inline] RIP: 0010:__rb_insert lib/rbtree.c:88 [inline] RIP: 0010:rb_insert_color+0x10/0x810 lib/rbtree.c:436 Code: 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 b8 00 00 00 00 00 fc ff df 41 57 <48> 89 fa 41 56 48 c1 ea 03 41 55 41 54 49 89 fc 55 53 48 83 ec 08 RSP: 0018:ffffc90000007e10 EFLAGS: 00000046 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000001 RDX: 1ffff110170850cb RSI: ffff8880b8428658 RDI: ffff88807c74e300 RBP: ffff8880b8428658 R08: 0000000000000005 R09: 000000000000001f R10: 0000000000000001 R11: 0000000000000001 R12: ffff88807c74e300 R13: ffff88807c74e318 R14: ffff8880b8428608 R15: ffff8880b8428658 FS: 00007f3acacc26c0(0000) GS:ffff888124372000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f748c645d58 CR3: 0000000084060000 CR4: 00000000003526f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 Call Trace: __rb_add include/linux/rbtree.h:239 [inline] rb_add_linked include/linux/rbtree.h:281 [inline] timerqueue_linked_add+0x236/0x430 lib/timerqueue.c:96 enqueue_hrtimer+0x1ad/0x2f0 kernel/time/hrtimer.c:1117 __run_hrtimer kernel/time/hrtimer.c:1946 [inline] __hrtimer_run_queues+0x73d/0xa00 kernel/time/hrtimer.c:1994 hrtimer_interrupt+0x3e5/0x940 kernel/time/hrtimer.c:2113 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline] __sysvec_apic_timer_interrupt+0x10b/0x460 arch/x86/kernel/apic/apic.c:1067 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1061 [inline] sysvec_apic_timer_interrupt+0x9e/0xc0 arch/x86/kernel/apic/apic.c:1061 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:179 [inline] RIP: 0010:_raw_spin_unlock_irqrestore+0x31/0x80 kernel/locking/spinlock.c:198 Code: f5 53 48 8b 74 24 10 48 89 fb 48 83 c7 18 e8 06 2a 57 f6 48 89 df e8 de 79 57 f6 f7 c5 00 02 00 00 75 23 9c 58 f6 c4 02 75 37 01 00 00 00 e8 65 49 47 f6 65 8b 05 1e 7f 7d 08 85 c0 74 16 5b RSP: 0018:ffffc9000456f838 EFLAGS: 00000246 RAX: 0000000000000002 RBX: ffff888072258f80 RCX: 0000000000000040 RDX: 0000000000000000 RSI: ffffffff8df20f0f RDI: ffffffff8c1c3780 RBP: 0000000000000282 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000001 R12: ffff888072258e10 R13: ffff888072258fc0 R14: ffff888072258968 R15: ffff8880775d4000 __unix_dgram_recvmsg+0x31a/0xc30 net/unix/af_unix.c:2612 unix_dgram_recvmsg+0xcd/0x100 net/unix/af_unix.c:2686 sock_recvmsg_nosec net/socket.c:1137 [inline] ____sys_recvmsg+0x5b3/0x640 net/socket.c:2916 ___sys_recvmsg+0x16a/0x1a0 net/socket.c:2960 do_recvmmsg+0x301/0x760 net/socket.c:3055 __sys_recvmmsg net/socket.c:3129 [inline] __do_sys_recvmmsg net/socket.c:3152 [inline] __se_sys_recvmmsg net/socket.c:3145 [inline] __x64_sys_recvmmsg+0x22a/0x280 net/socket.c:3145 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x10b/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f3ac9d9cdd9 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:00007f3acacc2028 EFLAGS: 00000246 ORIG_RAX: 000000000000012b RAX: ffffffffffffffda RBX: 00007f3aca016090 RCX: 00007f3ac9d9cdd9 RDX: 00000000080002c1 RSI: 0000200000000040 RDI: 0000000000000007 RBP: 00007f3ac9e32d69 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000002 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f3aca016128 R14: 00007f3aca016090 R15: 00007ffebb27e698