syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P4507/1:b..l P4523/1:b..l
	(detected by 0, t=10502 jiffies, g=10173, q=129 ncpus=2)
task:modprobe        state:R  running task     stack:24352 pid:4523  ppid:4490   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_irq+0xb1/0x150 kernel/sched/core.c:6873
 irqentry_exit+0x63/0x70 kernel/entry/common.c:439
 asm_sysvec_apic_timer_interrupt+0x16/0x20 arch/x86/include/asm/idtentry.h:691
RIP: 0010:__kasan_check_write+0x2/0x10 mm/kasan/shadow.c:37
Code: 0a 48 c7 c7 a3 a7 22 8c 48 89 de e8 e8 70 32 08 31 ed eb d7 00 00 cc cc 89 f6 48 8b 0c 24 31 d2 e9 a3 ec ff ff 0f 1f 00 89 f6 <48> 8b 0c 24 ba 01 00 00 00 e9 90 ec ff ff 55 41 56 53 48 89 d3 89
RSP: 0018:ffffc90004c1f878 EFLAGS: 00000293
RAX: ffffffff89fdac25 RBX: 0000000000000003 RCX: ffff888056c81dc0
RDX: 0000000000000000 RSI: 0000000000000004 RDI: ffffffff96e2f1c0
RBP: ffffc90004c1fa50 R08: ffff888056c81dc0 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: ffff88807e7f6f88
R13: ffff888074f9d480 R14: 0000000000000001 R15: 0000000000000300
 instrument_atomic_read_write include/linux/instrumented.h:102 [inline]
 atomic_inc include/linux/atomic/atomic-instrumented.h:190 [inline]
 mt_validate_nulls lib/maple_tree.c:7193 [inline]
 mt_validate+0x4426/0x4c90 lib/maple_tree.c:7244
 validate_mm_mt+0xcd/0x420 mm/mmap.c:294
 validate_mm+0xcc/0x2b0 mm/mmap.c:331
 do_mmap+0xc7/0xf30 mm/mmap.c:1269
 vm_mmap_pgoff+0x1b2/0x2b0 mm/util.c:520
 ksys_mmap_pgoff+0x516/0x6f0 mm/mmap.c:1478
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7ff112f64242
RSP: 002b:00007ffc102b1cd8 EFLAGS: 00000206 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007ff112c90000 RCX: 00007ff112f64242
RDX: 0000000000000005 RSI: 0000000000008000 RDI: 00007ff112c90000
RBP: 0000000000000812 R08: 0000000000000000 R09: 0000000000003000
R10: 0000000000000812 R11: 0000000000000206 R12: 00007ffc102b1d28
R13: 00007ff112f40b20 R14: 00007ffc102b2110 R15: 00000fff8205639e
 </TASK>
task:syz.2.46        state:R  running task     stack:24576 pid:4507  ppid:4264   flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 preempt_schedule_common+0x82/0xd0 kernel/sched/core.c:6730
 preempt_schedule+0xa7/0xb0 kernel/sched/core.c:6754
 preempt_schedule_thunk+0x16/0x18 arch/x86/entry/thunk_64.S:34
 __local_bh_enable_ip+0x13b/0x1b0 kernel/softirq.c:428
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 __fib6_clean_all+0x239/0x370 net/ipv6/ip6_fib.c:2262
 rt6_sync_down_dev net/ipv6/route.c:4944 [inline]
 rt6_disable_ip+0x120/0x7f0 net/ipv6/route.c:4949
 addrconf_ifdown+0x162/0x1a10 net/ipv6/addrconf.c:3804
 addrconf_notify+0x405/0xf40 net/ipv6/addrconf.c:-1
 notifier_call_chain kernel/notifier.c:87 [inline]
 raw_notifier_call_chain+0xcb/0x160 kernel/notifier.c:455
 call_netdevice_notifiers_mtu net/core/dev.c:2076 [inline]
 dev_set_mtu_ext+0x432/0x610 net/core/dev.c:8768
 dev_set_mtu+0x41/0xc0 net/core/dev.c:8789
 dev_ifsioc+0x490/0xe90 net/core/dev_ioctl.c:334
 dev_ioctl+0x578/0xea0 net/core/dev_ioctl.c:588
 sock_do_ioctl+0x222/0x2f0 net/socket.c:1218
 sock_ioctl+0x4ed/0x6e0 net/socket.c:1321
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7efee4b8e929
RSP: 002b:00007efee5973038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007efee4db5fa0 RCX: 00007efee4b8e929
RDX: 0000200000002280 RSI: 0000000000008922 RDI: 0000000000000005
RBP: 00007efee4c10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007efee4db5fa0 R15: 00007ffee7b4c3b8
 </TASK>
rcu: rcu_preempt kthread starved for 10572 jiffies! g10173 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=1
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:27840 pid:16    ppid:2      flags:0x00004000
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5244 [inline]
 __schedule+0x10e9/0x40d0 kernel/sched/core.c:6561
 schedule+0xb9/0x180 kernel/sched/core.c:6637
 schedule_timeout+0x15c/0x280 kernel/time/timer.c:1965
 rcu_gp_fqs_loop+0x2f2/0x1310 kernel/rcu/tree.c:1706
 rcu_gp_kthread+0x95/0x380 kernel/rcu/tree.c:1905
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>
rcu: Stack dump where RCU GP kthread last ran:
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1 skipped: idling at native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline]
NMI backtrace for cpu 1 skipped: idling at arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline]
NMI backtrace for cpu 1 skipped: idling at default_idle+0xb/0x10 arch/x86/kernel/process.c:741