syzbot


KCSAN: data-race in fasync_remove_entry / kill_fasync (7)

Status: auto-closed as invalid on 2022/01/18 10:05
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 392d, last: 353d
similar bugs (7):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (2) 1 831d 831d 0/24 auto-closed as invalid on 2020/09/27 12:17
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (4) 1 562d 562d 0/24 auto-closed as invalid on 2021/06/23 11:06
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (5) 2 493d 495d 0/24 auto-closed as invalid on 2021/08/31 22:21
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (3) 1 714d 714d 0/24 auto-closed as invalid on 2021/01/22 14:57
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (6) 1 432d 432d 0/24 auto-closed as invalid on 2021/10/31 16:09
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync (8) 3 298d 307d 0/24 auto-closed as invalid on 2022/03/14 14:59
upstream KCSAN: data-race in fasync_remove_entry / kill_fasync 82 885d 1043d 0/24 auto-closed as invalid on 2020/08/04 12:11

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

write to 0xffff8881377de958 of 8 bytes by task 13996 on cpu 0:
 fasync_remove_entry+0xd5/0x140 fs/fcntl.c:895
 fasync_helper+0x92/0xc0 fs/fcntl.c:994
 sock_fasync+0x5c/0xc0 net/socket.c:1339
 __fput+0x4dd/0x520 fs/file_table.c:277
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881377de958 of 8 bytes by task 13988 on cpu 1:
 kill_fasync+0x20/0x160 fs/fcntl.c:1033
 sock_wake_async+0xea/0x100
 sk_wake_async include/net/sock.h:2413 [inline]
 unix_release_sock+0x36c/0x680 net/unix/af_unix.c:570
 unix_release+0x4e/0x70 net/unix/af_unix.c:949
 __sock_release net/socket.c:649 [inline]
 sock_close+0x6c/0x150 net/socket.c:1314
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0x8e/0x110 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x160/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xd0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0xffff888104dad3c0 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13988 Comm: syz-executor.3 Not tainted 5.16.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (4):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/12/14 09:58 upstream 5472f14a3742 5d14b1ea .config log report info KCSAN: data-race in fasync_remove_entry / kill_fasync
ci2-upstream-kcsan-gce 2021/11/11 19:17 upstream debe436e77c7 75b04091 .config log report info KCSAN: data-race in fasync_remove_entry / kill_fasync
ci2-upstream-kcsan-gce 2021/11/10 23:44 upstream 89d714ab6043 75b04091 .config log report info KCSAN: data-race in fasync_remove_entry / kill_fasync
ci2-upstream-kcsan-gce 2021/11/06 01:58 upstream fe91c4725aee 4c1be0be .config log report info KCSAN: data-race in fasync_remove_entry / kill_fasync
* Struck through repros no longer work on HEAD.