syzbot


KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (3)

Status: auto-closed as invalid on 2022/09/16 09:55
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 108d, last: 108d
similar bugs (2):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (2) 1 273d 273d 0/24 auto-closed as invalid on 2022/04/03 20:50
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl 1 737d 717d 0/24 auto-closed as invalid on 2020/12/25 16:54

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

read-write to 0xffffffff870cfc30 of 8 bytes by task 15272 on cpu 1:
 do_epoll_ctl+0x641/0x890 fs/eventpoll.c:2137
 __do_sys_epoll_ctl fs/eventpoll.c:2214 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2205 [inline]
 __x64_sys_epoll_ctl+0xc2/0xf0 fs/eventpoll.c:2205
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffffff870cfc30 of 8 bytes by task 15276 on cpu 0:
 do_epoll_ctl+0x4ab/0x890 fs/eventpoll.c:2131
 __do_sys_epoll_ctl fs/eventpoll.c:2214 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2205 [inline]
 __x64_sys_epoll_ctl+0xc2/0xf0 fs/eventpoll.c:2205
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x000000000000005a -> 0x000000000000005c

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 15276 Comm: syz-executor.2 Not tainted 5.19.0-syzkaller-13930-g7ebfc85e2cd7-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/08/12 09:45 upstream 7ebfc85e2cd7 402cd70d .config log report info KCSAN: data-race in do_epoll_ctl / do_epoll_ctl
* Struck through repros no longer work on HEAD.