syzbot

rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
rcu: 	Tasks blocked on level-0 rcu_node (CPUs 0-1): P11129/2:b..l P10843/1:b..l
rcu: 	(detected by 0, t=10502 jiffies, g=59473, q=951 ncpus=1)
task:syz.2.1003      state:R  running task     stack:22472 pid:10843 tgid:10843 ppid:5828   task_flags:0x40064c flags:0x00080001
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 preempt_schedule_common+0x42/0xc0 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+0x3e/0x50 kernel/locking/spinlock.c:186
 spin_unlock include/linux/spinlock.h:389 [inline]
 zap_pte_range mm/memory.c:1959 [inline]
 zap_pmd_range mm/memory.c:2021 [inline]
 zap_pud_range mm/memory.c:2049 [inline]
 zap_p4d_range mm/memory.c:2070 [inline]
 unmap_page_range+0x2564/0x4840 mm/memory.c:2091
 unmap_single_vma+0x153/0x240 mm/memory.c:2133
 unmap_vmas+0x295/0x590 mm/memory.c:2171
 exit_mmap+0x1ef/0xa30 mm/mmap.c:1302
 __mmput+0x12a/0x410 kernel/fork.c:1175
 mmput+0x67/0x80 kernel/fork.c:1198
 exit_mm kernel/exit.c:581 [inline]
 do_exit+0x819/0x2b60 kernel/exit.c:964
 do_group_exit+0xd5/0x2a0 kernel/exit.c:1118
 get_signal+0x1ec7/0x21e0 kernel/signal.c:3034
 arch_do_signal_or_restart+0x91/0x770 arch/x86/kernel/signal.c:337
 __exit_to_user_mode_loop kernel/entry/common.c:64 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:98 [inline]
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline]
 irqentry_exit_to_user_mode_prepare include/linux/irq-entry-common.h:270 [inline]
 irqentry_exit_to_user_mode include/linux/irq-entry-common.h:339 [inline]
 irqentry_exit+0x1f8/0x670 kernel/entry/common.c:219
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:618
RIP: 0033:0x401000
RSP: 002b:000000000000000a EFLAGS: 00010206
RAX: 0000000000000000 RBX: 00007f065cc15fa0 RCX: 00007f065c99c799
RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000020003b46
RBP: 00007f065ca32c99 R08: 0000000000000002 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f065cc16038 R14: 00007f065cc15fa0 R15: 00007ffe3bc1a6a8
 </TASK>
task:syz.2.1071      state:R  running task     stack:26744 pid:11129 tgid:11126 ppid:5828   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0xfee/0x6120 kernel/sched/core.c:6911
 preempt_schedule_irq+0x50/0x90 kernel/sched/core.c:7238
 irqentry_exit+0x17b/0x670 kernel/entry/common.c:239
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:697
RIP: 0010:rt6_score_route+0x0/0xa60 net/ipv6/route.c:750
Code: e8 15 5b 3c f8 e9 f3 f1 ff ff e8 0b 5b 3c f8 e9 53 f1 ff ff 66 0f 1f 44 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <41> 57 41 56 41 55 41 89 cd 41 54 41 89 d4 55 48 89 fd 53 89 f3 48
RSP: 0018:ffffc90003786f90 EFLAGS: 00000246
RAX: 0000000000080000 RBX: ffff88805b489000 RCX: 0000000000000003
RDX: 0000000000000000 RSI: 0000000080200001 RDI: ffff88805b4890c8
RBP: ffff88805b489064 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000080200001
R13: ffff88805b4890df R14: 0000000000000000 R15: dffffc0000000000
 find_match net/ipv6/route.c:785 [inline]
 __find_rr_leaf+0x270/0x1070 net/ipv6/route.c:868
 find_rr_leaf net/ipv6/route.c:889 [inline]
 rt6_select net/ipv6/route.c:933 [inline]
 fib6_table_lookup+0x50f/0xa10 net/ipv6/route.c:2247
 ip6_pol_route+0x1cc/0x1230 net/ipv6/route.c:2283
 pol_lookup_func include/net/ip6_fib.h:617 [inline]
 fib6_rule_lookup+0x24c/0x720 net/ipv6/fib6_rules.c:120
 ip6_route_output_flags_noref net/ipv6/route.c:2698 [inline]
 ip6_route_output_flags+0x1d0/0x650 net/ipv6/route.c:2710
 ip6_dst_lookup_tail.constprop.0+0x116/0x2110 net/ipv6/ip6_output.c:1156
 ip6_dst_lookup_flow+0x99/0x1d0 net/ipv6/ip6_output.c:1259
 rawv6_sendmsg+0xe61/0x4420 net/ipv6/raw.c:894
 inet_sendmsg+0x11c/0x140 net/ipv4/af_inet.c:865
 sock_sendmsg_nosec net/socket.c:727 [inline]
 __sock_sendmsg net/socket.c:742 [inline]
 ____sys_sendmsg+0x98d/0xb70 net/socket.c:2592
 ___sys_sendmsg+0x190/0x1e0 net/socket.c:2646
 __sys_sendmmsg+0x205/0x430 net/socket.c:2735
 __do_sys_sendmmsg net/socket.c:2762 [inline]
 __se_sys_sendmmsg net/socket.c:2759 [inline]
 __x64_sys_sendmmsg+0x9c/0x100 net/socket.c:2759
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f065c99c799
RSP: 002b:00007f065d8e6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f065cc16090 RCX: 00007f065c99c799
RDX: 00000000000009a6 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 00007f065ca32c99 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000007000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f065cc16128 R14: 00007f065cc16090 R15: 00007ffe3bc1a6a8
 </TASK>