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BUG: KCSAN: data-race in can_receive / can_receive

read-write to 0xffff888104a45d68 of 8 bytes by interrupt on cpu 0:
 can_receive+0x62/0x1f0 net/can/af_can.c:651
 canfd_rcv+0xe7/0x180 net/can/af_can.c:703
 __netif_receive_skb_one_core net/core/dev.c:5893 [inline]
 __netif_receive_skb+0x123/0x280 net/core/dev.c:6006
 process_backlog+0x22e/0x440 net/core/dev.c:6354
 __napi_poll+0x63/0x3c0 net/core/dev.c:7188
 napi_poll net/core/dev.c:7257 [inline]
 net_rx_action+0x3a1/0x7f0 net/core/dev.c:7379
 handle_softirqs+0xbf/0x280 kernel/softirq.c:561
 do_softirq+0x5e/0x90 kernel/softirq.c:462
 __local_bh_enable_ip+0x6e/0x70 kernel/softirq.c:389
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:167 [inline]
 _raw_spin_unlock_bh+0x36/0x40 kernel/locking/spinlock.c:210
 spin_unlock_bh include/linux/spinlock.h:396 [inline]
 batadv_nc_purge_paths+0x220/0x270 net/batman-adv/network-coding.c:471
 batadv_nc_worker+0x3db/0xad0 net/batman-adv/network-coding.c:720
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3319
 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3400
 kthread+0x4ae/0x520 kernel/kthread.c:464
 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

read-write to 0xffff888104a45d68 of 8 bytes by interrupt on cpu 1:
 can_receive+0x62/0x1f0 net/can/af_can.c:651
 canfd_rcv+0xe7/0x180 net/can/af_can.c:703
 __netif_receive_skb_one_core net/core/dev.c:5893 [inline]
 __netif_receive_skb+0x123/0x280 net/core/dev.c:6006
 process_backlog+0x22e/0x440 net/core/dev.c:6354
 __napi_poll+0x63/0x3c0 net/core/dev.c:7188
 napi_poll net/core/dev.c:7257 [inline]
 net_rx_action+0x3a1/0x7f0 net/core/dev.c:7379
 handle_softirqs+0xbf/0x280 kernel/softirq.c:561
 do_softirq+0x5e/0x90 kernel/softirq.c:462
 __local_bh_enable_ip+0x6e/0x70 kernel/softirq.c:389
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 kfree_skb_napi_cache net/core/skbuff.c:7026 [inline]
 skb_attempt_defer_free+0x260/0x2c0 net/core/skbuff.c:7047
 tcp_eat_recv_skb net/ipv4/tcp.c:1527 [inline]
 tcp_recvmsg_locked+0x18e1/0x2040 net/ipv4/tcp.c:2819
 tcp_recvmsg+0x13c/0x490 net/ipv4/tcp.c:2865
 inet_recvmsg+0xbd/0x290 net/ipv4/af_inet.c:883
 sock_recvmsg_nosec net/socket.c:1023 [inline]
 sock_recvmsg+0xfe/0x170 net/socket.c:1045
 sock_read_iter+0x14c/0x1a0 net/socket.c:1115
 new_sync_read fs/read_write.c:484 [inline]
 vfs_read+0x5cc/0x6f0 fs/read_write.c:565
 ksys_read+0xe8/0x1b0 fs/read_write.c:708
 __do_sys_read fs/read_write.c:717 [inline]
 __se_sys_read fs/read_write.c:715 [inline]
 __x64_sys_read+0x42/0x50 fs/read_write.c:715
 x64_sys_call+0x2874/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:1
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000b41 -> 0x0000000000000b42

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 3288 Comm: syz-executor Tainted: G        W          6.14.0-rc6-syzkaller-00016-g0fed89a961ea #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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