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KCSAN: data-race in fasync_remove_entry / kill_fasync (4)

Status: auto-closed as invalid on 2021/06/23 11:06
Subsystems: fs
[Documentation on labels]
First crash: 1570d, last: 1570d
▶ ▼ Similar bugs (13)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (2) fs 6 1 1839d 1839d 0/29 auto-closed as invalid on 2020/09/27 12:17
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (10) fs 6 1 800d 800d 0/29 auto-obsoleted due to no activity on 2023/08/01 22:11
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (12) fs 6 1 300d 300d 0/29 auto-obsoleted due to no activity on 2025/01/04 10:04
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (5) fs 6 2 1500d 1502d 0/29 auto-closed as invalid on 2021/08/31 22:21
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (9) fs 6 1 1019d 1019d 0/29 auto-obsoleted due to no activity on 2023/01/02 11:50
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (13) fs 6 1 234d 234d 0/29 auto-obsoleted due to no activity on 2025/03/11 12:00
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (3) fs 6 1 1722d 1722d 0/29 auto-closed as invalid on 2021/01/22 14:57
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (11) fs 6 3 383d 412d 0/29 auto-obsoleted due to no activity on 2024/09/21 19:37
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (6) fs 6 1 1440d 1440d 0/29 auto-closed as invalid on 2021/10/31 16:09
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (7) fs 6 4 1361d 1399d 0/29 auto-closed as invalid on 2022/01/18 10:05
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (8) fs 6 3 1306d 1315d 0/29 auto-closed as invalid on 2022/03/14 14:59
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync fs 6 82 1893d 2050d 0/29 auto-closed as invalid on 2020/08/04 12:11
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (14) fs 6 2 6d13h 13d 0/29 moderation: reported on 2025/08/22 22:35

Sample crash report:
==================================================================
BUG: KCSAN: data-race in fasync_remove_entry / kill_fasync

write to 0xffff88810699fa58 of 8 bytes by task 5698 on cpu 0:
 fasync_remove_entry+0xd9/0x180 fs/fcntl.c:894
 fasync_helper+0x92/0xc0 fs/fcntl.c:993
 sock_fasync+0x5c/0xc0 net/socket.c:1283
 __fput+0x49f/0x4e0 fs/file_table.c:277
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff88810699fa58 of 8 bytes by task 5695 on cpu 1:
 kill_fasync+0x1e/0x160 fs/fcntl.c:1031
 sock_wake_async+0xea/0x100 net/socket.c:1312
 sk_wake_async include/net/sock.h:2311 [inline]
 unix_release_sock+0x383/0x6e0 net/unix/af_unix.c:553
 unix_release+0x2f/0x50 net/unix/af_unix.c:859
 __sock_release net/socket.c:599 [inline]
 sock_close+0x6c/0x150 net/socket.c:1258
 __fput+0x25b/0x4e0 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:174 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:208
 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:301
 do_syscall_64+0x56/0x90 arch/x86/entry/common.c:57
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5695 Comm: syz-executor.4 Not tainted 5.13.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2021/05/19 11:03 upstream 8ac91e6c6033 a343ba6b .config console log report info ci2-upstream-kcsan-gce KCSAN: data-race in fasync_remove_entry / kill_fasync
* Struck through repros no longer work on HEAD.