syzbot

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BUG: KCSAN: data-race in __packet_rcv_has_room / prb_retire_current_block

write to 0xffff888107858008 of 4 bytes by task 14735 on cpu 1:
 prb_flush_block net/packet/af_packet.c:776 [inline]
 prb_close_block net/packet/af_packet.c:832 [inline]
 prb_retire_current_block+0x1ad/0x240 net/packet/af_packet.c:972
 __packet_lookup_frame_in_block net/packet/af_packet.c:1096 [inline]
 packet_current_rx_frame net/packet/af_packet.c:1125 [inline]
 tpacket_rcv+0xd52/0x1a60 net/packet/af_packet.c:2359
 deliver_skb net/core/dev.c:2200 [inline]
 __netif_receive_skb_core+0x408/0x1e80 net/core/dev.c:5296
 __netif_receive_skb_one_core net/core/dev.c:5450 [inline]
 __netif_receive_skb+0x57/0x1b0 net/core/dev.c:5566
 netif_receive_skb_internal net/core/dev.c:5652 [inline]
 netif_receive_skb+0x4a/0x310 net/core/dev.c:5711
 tun_rx_batched+0x3bf/0x400
 tun_get_user+0x1d24/0x22b0 drivers/net/tun.c:1997
 tun_chr_write_iter+0x18e/0x240 drivers/net/tun.c:2043
 call_write_iter include/linux/fs.h:1877 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4ab/0x7d0 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888107858008 of 4 bytes by task 14740 on cpu 0:
 prb_lookup_block net/packet/af_packet.c:1141 [inline]
 __tpacket_v3_has_room net/packet/af_packet.c:1272 [inline]
 __packet_rcv_has_room+0x120/0x460 net/packet/af_packet.c:1295
 tpacket_rcv+0x275/0x1a60 net/packet/af_packet.c:2289
 deliver_skb net/core/dev.c:2200 [inline]
 __netif_receive_skb_core+0x408/0x1e80 net/core/dev.c:5296
 __netif_receive_skb_one_core net/core/dev.c:5450 [inline]
 __netif_receive_skb+0x57/0x1b0 net/core/dev.c:5566
 netif_receive_skb_internal net/core/dev.c:5652 [inline]
 netif_receive_skb+0x4a/0x310 net/core/dev.c:5711
 tun_rx_batched+0x3bf/0x400
 tun_get_user+0x1d24/0x22b0 drivers/net/tun.c:1997
 tun_chr_write_iter+0x18e/0x240 drivers/net/tun.c:2043
 call_write_iter include/linux/fs.h:1877 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x4ab/0x7d0 fs/read_write.c:584
 ksys_write+0xeb/0x1a0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14740 Comm: syz-executor.2 Not tainted 6.5.0-rc6-syzkaller-00027-g91aa6c412d7f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
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