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BUG: KCSAN: data-race in fasync_remove_entry / sock_wake_async

write to 0xffff888107261dd8 of 8 bytes by task 24706 on cpu 1:
 fasync_remove_entry+0xcc/0x120 fs/fcntl.c:1016
 fasync_helper+0x97/0xc0 fs/fcntl.c:1115
 sock_fasync+0x58/0xc0 net/socket.c:1539
 __fput+0x5d3/0x630 fs/file_table.c:507
 ____fput+0x1c/0x30 fs/file_table.c:538
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x1f4/0x6f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888107261dd8 of 8 bytes by task 24697 on cpu 0:
 sock_wake_async+0x29/0x110 net/socket.c:1554
 sk_wake_async_rcu include/net/sock.h:2593 [inline]
 unix_write_space+0x13b/0x140 net/unix/af_unix.c:607
 sock_wfree+0x149/0x3a0 net/core/sock.c:2696
 unix_wfree+0xc4/0xf0 net/unix/af_unix.c:1984
 skb_release_head_state+0x261/0x270 net/core/skbuff.c:1167
 skb_release_all net/core/skbuff.c:1187 [inline]
 __kfree_skb+0x18/0x150 net/core/skbuff.c:1203
 sk_skb_reason_drop+0xbd/0x230 net/core/skbuff.c:1241
 kfree_skb_reason include/linux/skbuff.h:1322 [inline]
 unix_release_sock+0x62e/0x750 net/unix/af_unix.c:726
 unix_release+0x58/0x80 net/unix/af_unix.c:1184
 __sock_release net/socket.c:722 [inline]
 sock_close+0x6b/0x150 net/socket.c:1514
 __fput+0x29b/0x630 fs/file_table.c:510
 ____fput+0x1c/0x30 fs/file_table.c:538
 task_work_run+0x130/0x1a0 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0x1f4/0x6f0 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:318 [inline]
 do_syscall_64+0x232/0x3b0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88811b04e510 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24697 Comm: syz.2.5991 Tainted: G        W           syzkaller #0 PREEMPT(full) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/18/2026
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