syzbot

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BUG: KCSAN: data-race in __rcu_read_unlock / rcu_preempt_deferred_qs_irqrestore

write to 0xffffffff85c7d198 of 8 bytes by task 9230 on cpu 1:
 rcu_preempt_deferred_qs_irqrestore+0x424/0x580 kernel/rcu/tree_plugin.h:498
 rcu_read_unlock_special kernel/rcu/tree_plugin.h:644 [inline]
 __rcu_read_unlock+0x16a/0x3d0 kernel/rcu/tree_plugin.h:383
 rcu_read_unlock include/linux/rcupdate.h:670 [inline]
 nf_hook include/linux/netfilter.h:264 [inline]
 __ip6_local_out+0x22d/0x2e0 net/ipv6/output_core.c:167
 ip6_local_out+0x31/0x90 net/ipv6/output_core.c:177
 ip6_send_skb+0x53/0x110 net/ipv6/ip6_output.c:1795
 ip6_push_pending_frames+0x9d/0xc0 net/ipv6/ip6_output.c:1815
 rawv6_push_pending_frames net/ipv6/raw.c:613 [inline]
 rawv6_sendmsg+0x1e59/0x2340 net/ipv6/raw.c:956
 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807
 sock_sendmsg_nosec net/socket.c:639 [inline]
 sock_sendmsg+0x9f/0xc0 net/socket.c:659
 ____sys_sendmsg+0x212/0x4d0 net/socket.c:2330
 ___sys_sendmsg+0xb5/0x100 net/socket.c:2384
 __sys_sendmmsg+0x123/0x350 net/socket.c:2474
 __do_sys_sendmmsg net/socket.c:2503 [inline]
 __se_sys_sendmmsg net/socket.c:2500 [inline]
 __x64_sys_sendmmsg+0x64/0x80 net/socket.c:2500
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff85c7d198 of 8 bytes by task 9225 on cpu 0:
 rcu_read_unlock_special kernel/rcu/tree_plugin.h:614 [inline]
 __rcu_read_unlock+0x1f6/0x3d0 kernel/rcu/tree_plugin.h:383
 rcu_read_unlock include/linux/rcupdate.h:670 [inline]
 filemap_map_pages+0x5b3/0x990 mm/filemap.c:2667
 do_fault_around mm/memory.c:3546 [inline]
 do_read_fault mm/memory.c:3580 [inline]
 do_fault mm/memory.c:3714 [inline]
 handle_pte_fault mm/memory.c:3945 [inline]
 __handle_mm_fault+0x2a92/0x2e00 mm/memory.c:4075
 handle_mm_fault+0x21b/0x530 mm/memory.c:4112
 do_user_addr_fault arch/x86/mm/fault.c:1441 [inline]
 __do_page_fault+0x456/0x8d0 arch/x86/mm/fault.c:1506
 do_page_fault+0x38/0x194 arch/x86/mm/fault.c:1530
 page_fault+0x34/0x40 arch/x86/entry/entry_64.S:1203

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 9225 Comm: udevd Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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