rcu: INFO: rcu_preempt detected stalls on CPUs/tasks: rcu: Tasks blocked on level-0 rcu_node (CPUs 0-1): P4952/1:b..l (detected by 1, t=10502 jiffies, g=11377, q=390) task:syz-executor state:R running task stack:21984 pid: 4952 ppid: 4948 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6571 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6596 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34 vprintk_emit+0x149/0x150 kernel/printk/printk.c:2275 _printk+0xcc/0x110 kernel/printk/printk.c:2299 batadv_check_known_mac_addr+0x27e/0x3b0 net/batman-adv/hard-interface.c:524 batadv_hard_if_event+0x4a0/0x17e0 net/batman-adv/hard-interface.c:986 notifier_call_chain kernel/notifier.c:83 [inline] raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:391 call_netdevice_notifiers_extack net/core/dev.c:2061 [inline] call_netdevice_notifiers net/core/dev.c:2075 [inline] dev_set_mac_address+0x2c4/0x3d0 net/core/dev.c:9114 dev_set_mac_address_user+0x2d/0x50 net/core/dev.c:9128 do_setlink+0x80d/0x3980 net/core/rtnetlink.c:2736 __rtnl_newlink net/core/rtnetlink.c:3452 [inline] rtnl_newlink+0x1419/0x17d0 net/core/rtnetlink.c:3574 rtnetlink_rcv_msg+0x7ff/0xe90 net/core/rtnetlink.c:5684 netlink_rcv_skb+0x1e0/0x430 net/netlink/af_netlink.c:2507 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline] netlink_unicast+0x774/0x920 net/netlink/af_netlink.c:1344 netlink_sendmsg+0x8ab/0xbc0 net/netlink/af_netlink.c:1918 sock_sendmsg_nosec net/socket.c:706 [inline] __sock_sendmsg net/socket.c:718 [inline] __sys_sendto+0x423/0x580 net/socket.c:2073 __do_sys_sendto net/socket.c:2085 [inline] __se_sys_sendto net/socket.c:2081 [inline] __x64_sys_sendto+0xda/0xf0 net/socket.c:2081 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x66/0xd0 RIP: 0033:0x7f0d4b184d0c RSP: 002b:00007ffde5e586c0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f0d4be4d620 RCX: 00007f0d4b184d0c RDX: 000000000000002c RSI: 00007f0d4be4d670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007ffde5e58714 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000003 R13: 0000000000000000 R14: 00007f0d4be4d670 R15: 0000000000000000 rcu: rcu_preempt kthread starved for 10541 jiffies! g11377 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:27880 pid: 15 ppid: 2 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5049 [inline] __schedule+0x11bb/0x4390 kernel/sched/core.c:6395 schedule+0x11b/0x1e0 kernel/sched/core.c:6478 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1914 rcu_gp_fqs_loop+0x29e/0x11b0 kernel/rcu/tree.c:1972 rcu_gp_kthread+0x98/0x350 kernel/rcu/tree.c:2145 kthread+0x436/0x520 kernel/kthread.c:334 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287 rcu: Stack dump where RCU GP kthread last ran: Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5340 Comm: syz.0.15 Not tainted syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:syscall_return_via_sysret+0x1b/0x5c Code: 48 83 bc 24 a0 00 00 00 2b 0f 85 9c 0d 00 00 66 90 b9 48 00 00 00 65 48 8b 14 25 e8 6f 02 00 83 e2 fe 89 d0 48 c1 ea 20 0f 30 <41> 5f 41 5e 41 5d 41 5c 5d 5b 41 5b 41 5a 41 59 41 58 58 59 5a 5e RSP: 0018:ffffc9000347ff58 EFLAGS: 00000046 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000048 RDX: 0000000000000000 RSI: ffffffff8a0b1c60 RDI: ffffffff8a59e580 RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ad33a6 R10: fffffbfff1ad33a6 R11: 0000000000000202 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 FS: 00007fbb4fc646c0(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000002006b000 CR3: 00000000208f1000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: RIP: 0033:0x7fbb509d6e27 Code: 0b e9 68 fe ff ff 48 83 c4 18 48 8d 3d 72 ba cd 00 5b 5d 41 5c 41 5d 41 5e 41 5f e9 33 f5 fb ff 0f 1f 00 b8 27 00 00 00 0f 05 0f 1f 84 00 00 00 00 00 b8 66 00 00 00 0f 05 c3 0f 1f 84 00 00 RSP: 002b:00007fbb4fc63b08 EFLAGS: 00000202 ORIG_RAX: 0000000000000027 RAX: 0000000000000003 RBX: 00007fbb4fc63c70 RCX: 00007fbb509d6e27 RDX: 00007fbb4fc63b40 RSI: 00007fbb4fc63c70 RDI: 0000000000000021 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000202 R12: 00007fbb50b7bf8c R13: 0000000000000000 R14: 00007ffcb00bf8d0 R15: 00007ffcb00bf9b8