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KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (5)

Status: moderation: reported on 2024/03/18 09:35
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+842f25b7b118d03fc6a2@syzkaller.appspotmail.com
First crash: 26d, last: 26d
Similar bugs (4)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (4) fs 1 301d 301d 0/26 auto-obsoleted due to no activity on 2023/07/22 09:13
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (2) fs 1 776d 776d 0/26 auto-closed as invalid on 2022/04/03 20:50
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl fs 1 1240d 1219d 0/26 auto-closed as invalid on 2020/12/25 16:54
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (3) fs 1 610d 610d 0/26 auto-closed as invalid on 2022/09/16 09:55

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

read-write to 0xffffffff883d72c0 of 8 bytes by task 15441 on cpu 1:
 do_epoll_ctl+0x6f6/0x950 fs/eventpoll.c:2303
 __do_sys_epoll_ctl fs/eventpoll.c:2386 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2377 [inline]
 __x64_sys_epoll_ctl+0xc6/0xf0 fs/eventpoll.c:2377
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

read to 0xffffffff883d72c0 of 8 bytes by task 15443 on cpu 0:
 do_epoll_ctl+0x529/0x950 fs/eventpoll.c:2297
 __do_sys_epoll_ctl fs/eventpoll.c:2386 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2377 [inline]
 __x64_sys_epoll_ctl+0xc6/0xf0 fs/eventpoll.c:2377
 do_syscall_64+0xd3/0x1d0
 entry_SYSCALL_64_after_hwframe+0x6d/0x75

value changed: 0x000000000000000a -> 0x000000000000000c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15443 Comm: syz-executor.2 Tainted: G        W          6.8.0-syzkaller-11409-gf6cef5f8c37f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/29/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/03/18 09:34 upstream f6cef5f8c37f d615901c .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in do_epoll_ctl / do_epoll_ctl
* Struck through repros no longer work on HEAD.