syzbot

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BUG: KCSAN: data-race in cleanup_net / synchronize_net

write to 0xffffffff88fec498 of 8 bytes by task 3434 on cpu 0:
 cleanup_net+0x50/0x4d0 net/core/net_namespace.c:657
 process_one_work kernel/workqueue.c:3238 [inline]
 process_scheduled_works+0x4cb/0x9d0 kernel/workqueue.c:3321
 worker_thread+0x582/0x770 kernel/workqueue.c:3402
 kthread+0x486/0x510 kernel/kthread.c:464
 ret_from_fork+0xda/0x150 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffffffff88fec498 of 8 bytes by task 9187 on cpu 1:
 from_cleanup_net net/core/dev.c:10501 [inline]
 synchronize_net+0x24/0x70 net/core/dev.c:11925
 packet_release+0x5d2/0x810 net/packet/af_packet.c:3217
 __sock_release net/socket.c:647 [inline]
 sock_close+0x68/0x150 net/socket.c:1391
 __fput+0x298/0x650 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 exit_task_work include/linux/task_work.h:40 [inline]
 do_exit+0x47f/0x1590 kernel/exit.c:955
 do_group_exit+0xff/0x140 kernel/exit.c:1104
 get_signal+0xe59/0xf70 kernel/signal.c:3034
 arch_do_signal_or_restart+0x96/0x480 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 irqentry_exit_to_user_mode+0x5e/0xa0 kernel/entry/common.c:184
 irqentry_exit+0x12/0x50 kernel/entry/common.c:287
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x0000000000000000 -> 0xffff888104278000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 9187 Comm: syz.6.10189 Not tainted 6.15.0-syzkaller-11173-g546b1c9e93c2 #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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