syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P5910/1:b..l
rcu: 	(detected by 1, t=10503 jiffies, g=11117, q=560 ncpus=2)
task:syz-executor    state:R  running task     stack:22280 pid:5910  ppid:5905   flags:0x00004002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:preempt_schedule+0x92/0xd0 kernel/sched/core.c:6892
Code: 48 b8 04 00 00 00 00 fc ff df c6 04 03 00 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f7 44 24 20 00 02 00 00 c6 04 03 f8 75 29 <48> c7 04 24 0e 36 e0 45 4a c7 04 33 00 00 00 00 65 48 8b 04 25 28
RSP: 0018:ffffc900032e6960 EFLAGS: 00000246
RAX: 1ffff11004953b40 RBX: 1ffff9200065cd2c RCX: 96572b2a9bc3aa00
RDX: dffffc0000000000 RSI: ffffffff8acacb60 RDI: ffff888024a9eff8
RBP: ffffc900032e69d8 R08: ffffffff911bc5c7 R09: 1ffffffff22378b8
R10: dffffc0000000000 R11: fffffbfff22378b9 R12: dffffc0000000000
R13: 1ffff9200065cd4c R14: dffffc0000000000 R15: 000000000000005d
 preempt_schedule_thunk+0x1a/0x30 arch/x86/entry/thunk_64.S:45
 vprintk_emit+0x587/0x610 kernel/printk/printk.c:2342
 _printk+0xde/0x130 kernel/printk/printk.c:2366
 batadv_check_known_mac_addr+0x29a/0x3e0 net/batman-adv/hard-interface.c:526
 batadv_hard_if_event+0x3a2/0x1570 net/batman-adv/hard-interface.c:998
 notifier_call_chain+0x18f/0x380 kernel/notifier.c:93
 call_netdevice_notifiers_extack net/core/dev.c:2077 [inline]
 call_netdevice_notifiers net/core/dev.c:2091 [inline]
 dev_set_mac_address+0x38e/0x4d0 net/core/dev.c:8986
 dev_set_mac_address_user+0x31/0x50 net/core/dev.c:9000
 do_setlink+0x78f/0x3f40 net/core/rtnetlink.c:2864
 __rtnl_newlink net/core/rtnetlink.c:3707 [inline]
 rtnl_newlink+0x1848/0x2170 net/core/rtnetlink.c:3754
 rtnetlink_rcv_msg+0x843/0xf90 net/core/rtnetlink.c:6476
 netlink_rcv_skb+0x235/0x4c0 net/netlink/af_netlink.c:2550
 netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
 netlink_unicast+0x7b1/0x930 net/netlink/af_netlink.c:1346
 netlink_sendmsg+0x8d0/0xbf0 net/netlink/af_netlink.c:1899
 sock_sendmsg_nosec net/socket.c:730 [inline]
 __sock_sendmsg net/socket.c:745 [inline]
 __sys_sendto+0x4a9/0x6b0 net/socket.c:2201
 __do_sys_sendto net/socket.c:2213 [inline]
 __se_sys_sendto net/socket.c:2209 [inline]
 __x64_sys_sendto+0xde/0xf0 net/socket.c:2209
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fd26ff5d68e
RSP: 002b:00007ffc405abb98 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000555562d90500 RCX: 00007fd26ff5d68e
RDX: 000000000000002c RSI: 00007fd270d44670 RDI: 0000000000000003
RBP: 0000000000000001 R08: 00007ffc405abc14 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 00007fd270d44670 R15: 0000000000000000
 </TASK>
rcu: rcu_preempt kthread starved for 10560 jiffies! g11117 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:26856 pid:17    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5381 [inline]
 __schedule+0x15ae/0x4660 kernel/sched/core.c:6700
 preempt_schedule_irq+0xbf/0x150 kernel/sched/core.c:7010
 irqentry_exit+0x67/0x70 kernel/entry/common.c:438
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:__timer_delete_sync+0x275/0x2e0 kernel/time/timer.c:1582
Code: 00 00 fc ff df 49 c7 44 05 00 00 00 00 00 41 c7 44 05 08 00 00 00 00 65 48 8b 04 25 28 00 00 00 48 3b 84 24 80 00 00 00 75 1b <44> 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 84 8f 10
RSP: 0018:ffffc90000167aa0 EFLAGS: 00000246
RAX: f8f38a1d3f93a500 RBX: ffffc90000167ba0 RCX: ffff88801b648000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90000167b70 R08: ffffffff8e8ae5ef R09: 1ffffffff1d15cbd
R10: dffffc0000000000 R11: fffffbfff1d15cbe R12: ffffffff8176544e
R13: 1ffff9200002cf58 R14: 0000000000000000 R15: 0000000000000000
 timer_delete_sync kernel/time/timer.c:1629 [inline]
 del_timer_sync include/linux/timer.h:200 [inline]
 schedule_timeout+0x192/0x2d0 kernel/time/timer.c:2169
 rcu_gp_fqs_loop+0x30d/0x1590 kernel/rcu/tree.c:1667
 rcu_gp_kthread+0x9d/0x3b0 kernel/rcu/tree.c:1866
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>
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: 6188 Comm: syz.2.19 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:__lock_acquire+0xe4a/0x7d80 kernel/locking/lockdep.c:5120
Code: 00 00 84 c9 0f 84 60 0a 00 00 48 89 d8 48 c1 e8 03 42 80 3c 00 00 74 12 48 89 df e8 10 44 77 00 49 b8 00 00 00 00 00 fc ff df <4c> 89 3b 48 8b 44 24 78 42 0f b6 04 00 84 c0 0f 85 a5 0d 00 00 48
RSP: 0018:ffffc900043174c0 EFLAGS: 00000046
RAX: 1ffff11005a92161 RBX: ffff88802d490b08 RCX: ffffffff816815a2
RDX: 0000000000000000 RSI: 0000000000000008 RDI: ffffffff911bc510
RBP: ffffc90004317708 R08: dffffc0000000000 R09: 1ffffffff22378a2
R10: dffffc0000000000 R11: fffffbfff22378a3 R12: 0000000000040000
R13: ffff88802d490000 R14: ffff88802d490ad0 R15: 21172683b190bb39
FS:  00007ff11530f6c0(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000200000000058 CR3: 0000000060c70000 CR4: 00000000003506f0
Call Trace:
 <TASK>
 lock_acquire+0x19e/0x420 kernel/locking/lockdep.c:5754
 do_write_seqcount_begin_nested include/linux/seqlock.h:515 [inline]
 do_write_seqcount_begin include/linux/seqlock.h:541 [inline]
 psi_write_begin kernel/sched/psi.c:179 [inline]
 psi_account_irqtime+0x236/0x810 kernel/sched/psi.c:1034
 __schedule+0x8c8/0x4660 kernel/sched/core.c:6694
 schedule+0xbd/0x170 kernel/sched/core.c:6774
 futex_wait_queue+0x138/0x1b0 kernel/futex/waitwake.c:355
 futex_wait+0x1e9/0x5c0 kernel/futex/waitwake.c:656
 do_futex+0x2ff/0x3e0 kernel/futex/syscalls.c:134
 __do_sys_futex kernel/futex/syscalls.c:211 [inline]
 __se_sys_futex+0x3a9/0x440 kernel/futex/syscalls.c:192
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff11439ce59
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:00007ff11530f0e8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: ffffffffffffffda RBX: 00007ff114615fa8 RCX: 00007ff11439ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007ff114615fa8
RBP: 00007ff114615fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ff114616038 R14: 00007ffcc7ec0b90 R15: 00007ffcc7ec0c78
 </TASK>
sched: RT throttling activated