syzbot


KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (2)

Status: auto-closed as invalid on 2022/04/03 20:50
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 278d, last: 278d
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 1 742d 722d 0/24 auto-closed as invalid on 2020/12/25 16:54
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (3) 1 113d 113d 0/24 auto-closed as invalid on 2022/09/16 09:55

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

write to 0xffffffff86df1a70 of 8 bytes by task 22591 on cpu 0:
 do_epoll_ctl+0x1786/0x1880 fs/eventpoll.c:2166
 __do_sys_epoll_ctl fs/eventpoll.c:2192 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2183 [inline]
 __x64_sys_epoll_ctl+0xc2/0xf0 fs/eventpoll.c:2183
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffffffff86df1a70 of 8 bytes by task 22593 on cpu 1:
 do_epoll_ctl+0x3ce/0x1880 fs/eventpoll.c:2109
 __do_sys_epoll_ctl fs/eventpoll.c:2192 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2183 [inline]
 __x64_sys_epoll_ctl+0xc2/0xf0 fs/eventpoll.c:2183
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000000000000003 -> 0x0000000000000004

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 22593 Comm: syz-executor.4 Not tainted 5.17.0-rc5-syzkaller-00306-g2293be58d6a1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2022/02/27 20:40 upstream 2293be58d6a1 45a13a73 .config log report info KCSAN: data-race in do_epoll_ctl / do_epoll_ctl
* Struck through repros no longer work on HEAD.