syzbot

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BUG: KCSAN: data-race in fasync_remove_entry / sock_wake_async

write to 0xffff8880bb2cf398 of 8 bytes by task 28343 on cpu 0:
 fasync_remove_entry+0xb7/0x120 fs/fcntl.c:884
 fasync_helper+0xc9/0xd6 fs/fcntl.c:983
 sock_fasync+0x74/0x100 net/socket.c:1308
 __fput+0x455/0x500 fs/file_table.c:277
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880bb2cf398 of 8 bytes by task 28341 on cpu 1:
 sock_wake_async+0x37/0x100 net/socket.c:1323
 sk_wake_async include/net/sock.h:2259 [inline]
 sk_wake_async include/net/sock.h:2255 [inline]
 unix_write_space+0x166/0x180 net/unix/af_unix.c:466
 sock_wfree+0x13e/0x1b0 net/core/sock.c:1969
 unix_destruct_scm+0xd2/0x100 net/unix/scm.c:149
 skb_release_head_state+0xb0/0x180 net/core/skbuff.c:651
 skb_release_all+0x1b/0x50 net/core/skbuff.c:662
 __kfree_skb net/core/skbuff.c:678 [inline]
 kfree_skb net/core/skbuff.c:696 [inline]
 kfree_skb+0x93/0x200 net/core/skbuff.c:690
 unix_release_sock+0x304/0x670 net/unix/af_unix.c:568
 unix_release+0x3a/0x60 net/unix/af_unix.c:867
 __sock_release+0x85/0x160 net/socket.c:605
 sock_close+0x1f/0x30 net/socket.c:1283
 __fput+0x1e9/0x500 fs/file_table.c:280
 ____fput+0x1b/0x30 fs/file_table.c:313
 task_work_run+0xba/0x120 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2ae/0x2c0 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x38b/0x3b0 arch/x86/entry/common.c:305
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 28341 Comm: syz-executor.5 Not tainted 5.7.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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