syzbot


KCSAN: data-race in __fput / ep_remove (3)

Status: auto-obsoleted due to no activity on 2023/04/06 07:53
Subsystems: fs
[Documentation on labels]
First crash: 381d, last: 381d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __fput / ep_remove (2) fs 2 645d 673d 0/26 auto-closed as invalid on 2022/06/25 02:37
upstream KCSAN: data-race in __fput / ep_remove fs 1 1033d 1033d 0/26 auto-closed as invalid on 2021/06/02 19:47

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

write to 0xffff888104eaa9d0 of 8 bytes by task 8937 on cpu 1:
 ep_remove+0x336/0x390 fs/eventpoll.c:706
 ep_free+0x164/0x1f0 fs/eventpoll.c:780
 ep_eventpoll_release+0x32/0x40 fs/eventpoll.c:797
 __fput+0x245/0x570 fs/file_table.c:320
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x123/0x160 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xcf/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888104eaa9d0 of 8 bytes by task 8933 on cpu 0:
 eventpoll_release include/linux/eventpoll.h:45 [inline]
 __fput+0x1c8/0x570 fs/file_table.c:311
 ____fput+0x15/0x20 fs/file_table.c:348
 task_work_run+0x123/0x160 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xcf/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0xffff888104863920 -> 0x0000000000000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 8933 Comm: syz-executor.1 Tainted: G        W          6.2.0-rc7-syzkaller-00018-g0983f6bf2bfc-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/02/09 07:34 upstream 0983f6bf2bfc 14a312c8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in __fput / ep_remove
* Struck through repros no longer work on HEAD.