syzbot

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BUG: KCSAN: data-race in fasync_remove_entry / sock_wake_async

write to 0xffff8881067dca18 of 8 bytes by task 10312 on cpu 1:
 fasync_remove_entry+0xd2/0x130 fs/fcntl.c:1005
 fasync_helper+0x96/0xc0 fs/fcntl.c:1104
 sock_fasync+0x5a/0xc0 net/socket.c:1423
 __fput+0x5d2/0x640 fs/file_table.c:461
 ____fput+0x1c/0x30 fs/file_table.c:492
 task_work_run+0x13a/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff8881067dca18 of 8 bytes by task 10311 on cpu 0:
 sock_wake_async+0x2a/0x120 net/socket.c:1438
 sk_wake_async_rcu include/net/sock.h:2474 [inline]
 unix_write_space+0x135/0x140 net/unix/af_unix.c:613
 sock_wfree+0x147/0x3b0 net/core/sock.c:2588
 unix_destruct_scm+0xc5/0xf0 net/unix/af_unix.c:1879
 skb_release_head_state+0xbb/0x1b0 net/core/skbuff.c:1087
 skb_release_all net/core/skbuff.c:1098 [inline]
 __kfree_skb+0x16/0x150 net/core/skbuff.c:1114
 sk_skb_reason_drop+0xba/0x290 net/core/skbuff.c:1152
 kfree_skb_reason include/linux/skbuff.h:1271 [inline]
 unix_release_sock+0x603/0x750 net/unix/af_unix.c:721
 unix_release+0x57/0x80 net/unix/af_unix.c:1106
 __sock_release net/socket.c:647 [inline]
 sock_close+0x68/0x150 net/socket.c:1398
 __fput+0x2ac/0x640 fs/file_table.c:464
 ____fput+0x1c/0x30 fs/file_table.c:492
 task_work_run+0x13a/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0xa8/0x120 kernel/entry/common.c:218
 do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff8881187c4a20 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 10311 Comm: syz.4.2608 Tainted: G        W          6.14.0-rc4-syzkaller-00052-gac9c34d1e45a #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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