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KCSAN: data-race in __ep_remove / __fput (2)

Status: auto-obsoleted due to no activity on 2023/09/09 12:48
Subsystems: fs
[Documentation on labels]
First crash: 886d, last: 886d
▶ ▼ Similar bugs (4)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __ep_remove / __fput (3) fs 6 1 699d 699d 0/29 auto-obsoleted due to no activity on 2024/03/14 21:07
upstream KCSAN: data-race in __ep_remove / __fput (5) fs 6 1 474d 473d 28/29 fixed on 2024/12/16 09:50
upstream KCSAN: data-race in __ep_remove / __fput fs 6 1 927d 927d 0/29 auto-obsoleted due to no activity on 2023/07/30 19:06
upstream KCSAN: data-race in __ep_remove / __fput (4) fs 6 1 555d 552d 0/29 auto-obsoleted due to no activity on 2024/08/05 15:52

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __ep_remove / __fput

write to 0xffff8881036624d0 of 8 bytes by task 21030 on cpu 1:
 __ep_remove+0x3b4/0x440 fs/eventpoll.c:744
 ep_remove_safe fs/eventpoll.c:782 [inline]
 ep_clear_and_put+0x158/0x250 fs/eventpoll.c:818
 ep_eventpoll_release+0x32/0x40 fs/eventpoll.c:834
 __fput+0x303/0x600 fs/file_table.c:384
 ____fput+0x15/0x20 fs/file_table.c:412
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd1/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff8881036624d0 of 8 bytes by task 21027 on cpu 0:
 eventpoll_release include/linux/eventpoll.h:45 [inline]
 __fput+0x280/0x600 fs/file_table.c:375
 ____fput+0x15/0x20 fs/file_table.c:412
 task_work_run+0x135/0x1a0 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd1/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:297
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffff888123f6cd60 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 21027 Comm: syz-executor.0 Not tainted 6.5.0-rc4-syzkaller-00227-g024ff300db33 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/05 12:43 upstream 024ff300db33 4ffcc9ef .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __ep_remove / __fput
* Struck through repros no longer work on HEAD.