rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P2556/1:b..l P2208/1:b..l rcu: (detected by 1, t=10502 jiffies, g=284293, q=529 ncpus=2) task:syz-executor state:R running task stack:22152 pid:2208 tgid:2208 ppid:2188 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:7095 preempt_schedule_thunk+0x16/0x30 arch/x86/entry/thunk.S:12 __raw_spin_unlock include/linux/spinlock_api_smp.h:169 [inline] _raw_spin_unlock+0x3f/0x50 kernel/locking/spinlock.c:186 spin_unlock include/linux/spinlock.h:389 [inline] copy_pte_range mm/memory.c:1344 [inline] copy_pmd_range+0x75a1/0x8050 mm/memory.c:1405 copy_pud_range mm/memory.c:1442 [inline] copy_p4d_range mm/memory.c:1466 [inline] copy_page_range+0xbe8/0x11f0 mm/memory.c:1552 dup_mmap+0xf40/0x1d90 mm/mmap.c:1841 dup_mm kernel/fork.c:1531 [inline] copy_mm+0x13b/0x4a0 kernel/fork.c:1583 copy_process+0x18b6/0x3cd0 kernel/fork.c:2223 kernel_clone+0x248/0x8e0 kernel/fork.c:2653 __do_sys_clone kernel/fork.c:2794 [inline] __se_sys_clone kernel/fork.c:2778 [inline] __x64_sys_clone+0x1b6/0x230 kernel/fork.c:2778 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: 0033:0x7f6b2c7c5212 RSP: 002b:00007f6b2cb3fc60 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f6b2cb3fc60 RCX: 00007f6b2c7c5212 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 00007f6b2cb3fdec R08: 0000000000000000 R09: 0000000000000001 R10: 000055558b3577d0 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000000927c0 R14: 0000000000212c1a R15: 00007f6b2cb3fe40 task:syz-executor state:R running task stack:22184 pid:2556 tgid:2556 ppid:2537 task_flags:0x400140 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 preempt_schedule_irq+0x4d/0xa0 kernel/sched/core.c:7238 irqentry_exit+0x599/0x620 kernel/entry/common.c:239 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697 RIP: 0010:batadv_hardif_get_by_netdev+0x15f/0x3d0 net/batman-adv/hard-interface.c:73 Code: f6 4c 8b 3d f3 1e 06 0f 49 81 ff e0 50 7f 9a 0f 84 a8 01 00 00 4c 89 6c 24 10 49 8d 5f 18 48 89 d8 48 c1 e8 03 42 80 3c 20 00 <74> 08 48 89 df e8 f7 c9 b6 f6 4c 39 2b 74 0a e8 cd 7c 4c f6 e9 fd RSP: 0018:ffffc90004e86860 EFLAGS: 00000246 RAX: 1ffff1100ab05803 RBX: ffff88805582c018 RCX: ffff888054249e80 RDX: 0000000000000000 RSI: ffffffff8c27cfe0 RDI: ffffffff8c27cfa0 RBP: ffffc90004e86908 R08: ffffffff8b793129 R09: ffffffff8e75e5e0 R10: dffffc0000000000 R11: ffffffff8b797100 R12: dffffc0000000000 R13: ffff88806ba40000 R14: 1ffff920009d0d10 R15: ffff88805582c000 batadv_hard_if_event+0x82/0x1700 net/batman-adv/hard-interface.c:955 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85 netif_state_change+0x27d/0x3a0 net/core/dev.c:1603 netif_set_operstate+0x11c/0x190 net/core/rtnetlink.c:1063 hsr_set_operstate net/hsr/hsr_device.c:-1 [inline] hsr_check_carrier_and_operstate+0x298/0x5c0 net/hsr/hsr_device.c:98 hsr_netdev_notify+0x40c/0xce0 net/hsr/hsr_main.c:60 notifier_call_chain+0x1be/0x400 kernel/notifier.c:85 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline] call_netdevice_notifiers net/core/dev.c:2301 [inline] __dev_notify_flags+0x1a9/0x310 net/core/dev.c:9815 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9844 do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3180 rtnl_changelink net/core/rtnetlink.c:3798 [inline] __rtnl_newlink net/core/rtnetlink.c:3957 [inline] rtnl_newlink+0x15a9/0x1be0 net/core/rtnetlink.c:4094 rtnetlink_rcv_msg+0x7d5/0xbe0 net/core/rtnetlink.c:6980 netlink_rcv_skb+0x232/0x4b0 net/netlink/af_netlink.c:2550 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x80f/0x9b0 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894 sock_sendmsg_nosec net/socket.c:727 [inline] __sock_sendmsg net/socket.c:742 [inline] __sys_sendto+0x672/0x710 net/socket.c:2206 __do_sys_sendto net/socket.c:2213 [inline] __se_sys_sendto net/socket.c:2209 [inline] __x64_sys_sendto+0xde/0x100 net/socket.c:2209 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: 0033:0x7f4a68d5cfce RSP: 002b:00007f4a6913f608 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000555555c1b500 RCX: 00007f4a68d5cfce RDX: 0000000000000020 RSI: 00007f4a69b44670 RDI: 0000000000000003 RBP: 0000000000000001 R08: 00007f4a6913f684 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f4a69b44670 R15: 0000000000000000 rcu: rcu_preempt kthread timer wakeup didn't happen for 10501 jiffies! g284293 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x402 rcu: Possible timer handling issue on cpu=0 timer-softirq=191652 rcu: rcu_preempt kthread starved for 10502 jiffies! g284293 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:27744 pid:16 tgid:16 ppid:2 task_flags:0x208040 flags:0x00080000 Call Trace: context_switch kernel/sched/core.c:5298 [inline] __schedule+0x15dd/0x52d0 kernel/sched/core.c:6911 __schedule_loop kernel/sched/core.c:6993 [inline] schedule+0x164/0x360 kernel/sched/core.c:7008 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:436 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: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 2675 Comm: syz.9.8634 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026 RIP: 0010:num_possible_cpus include/linux/cpumask.h:1222 [inline] RIP: 0010:mm_get_cid kernel/sched/sched.h:3850 [inline] RIP: 0010:sched_mm_cid_fork+0x5b0/0x1120 kernel/sched/core.c:10679 Code: 00 00 31 ed 31 db e9 7b 01 00 00 49 c7 c4 98 2e 1b 8e 49 c1 ec 03 41 bd 00 00 00 80 eb 0a 89 e8 f7 d8 0f 81 e3 fe ff ff f3 90 <48> b8 00 00 00 00 00 fc ff df 41 0f b6 04 04 84 c0 75 40 44 8b 35 RSP: 0018:ffffc9000666fc48 EFLAGS: 00000887 RAX: 0000000080000000 RBX: ffff8880324d17d0 RCX: 0000000080000001 RDX: dffffc0000000000 RSI: 0000000000000002 RDI: ffff8880324d17d0 RBP: 0000000080000000 R08: 1ffff1100649a1a9 R09: 0000000000000000 R10: ffff8880324d0e94 R11: fffff52000ccdf78 R12: 1ffffffff1c365d3 R13: 0000000080000000 R14: 0000000000000002 R15: ffff8880324d0c40 FS: 00007f72e21f66c0(0000) GS:ffff888125457000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f883434da08 CR3: 000000004d7cc000 CR4: 00000000003526f0 DR0: ffffffffffffffff DR1: 00000000000001f8 DR2: 0000000000000083 DR3: ffffffffefffff15 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: bprm_execve+0xda1/0x1460 fs/exec.c:1771 do_execveat_common+0x50d/0x690 fs/exec.c:1846 __do_sys_execveat fs/exec.c:1941 [inline] __se_sys_execveat fs/exec.c:1934 [inline] __x64_sys_execveat+0xc7/0xf0 fs/exec.c:1934 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: 0033:0x7f72e3f9c799 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:00007f72e21f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000142 RAX: ffffffffffffffda RBX: 00007f72e4215fa0 RCX: 00007f72e3f9c799 RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000008 RBP: 00007f72e4032c99 R08: 0000000000001000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f72e4216038 R14: 00007f72e4215fa0 R15: 00007f72e433fa48