syzbot


KCSAN: data-race in do_epoll_ctl / do_epoll_ctl

Status: auto-closed as invalid on 2020/12/25 16:54
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+60e80f7ef1c268ce31a5@syzkaller.appspotmail.com
First crash: 1284d, last: 1284d
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 345d 345d 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 820d 820d 0/26 auto-closed as invalid on 2022/04/03 20:50
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (5) fs 1 70d 70d 0/26 auto-obsoleted due to no activity on 2024/04/22 09:35
upstream KCSAN: data-race in do_epoll_ctl / do_epoll_ctl (3) fs 1 654d 654d 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 0xffffffff883159e8 of 8 bytes by task 12917 on cpu 1:
 do_epoll_ctl+0x41a/0x1c10 fs/eventpoll.c:2191
 __do_sys_epoll_ctl fs/eventpoll.c:2281 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2272 [inline]
 __x64_sys_epoll_ctl+0xb3/0xe0 fs/eventpoll.c:2272
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffffff883159e8 of 8 bytes by task 12916 on cpu 0:
 do_epoll_ctl+0x367/0x1c10 fs/eventpoll.c:2185
 __do_sys_epoll_ctl fs/eventpoll.c:2281 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2272 [inline]
 __x64_sys_epoll_ctl+0xb3/0xe0 fs/eventpoll.c:2272
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12916 Comm: systemd-udevd Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 12916 Comm: systemd-udevd Not tainted 5.10.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x116/0x15d lib/dump_stack.c:118
 panic+0x1e7/0x5fa kernel/panic.c:231
 kcsan_report+0x67b/0x680 kernel/kcsan/report.c:634
 kcsan_setup_watchpoint+0x46a/0x4d0 kernel/kcsan/core.c:568
 do_epoll_ctl+0x367/0x1c10 fs/eventpoll.c:2185
 __do_sys_epoll_ctl fs/eventpoll.c:2281 [inline]
 __se_sys_epoll_ctl fs/eventpoll.c:2272 [inline]
 __x64_sys_epoll_ctl+0xb3/0xe0 fs/eventpoll.c:2272
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f4c9156b2aa
Code: 48 8b 0d f1 fb 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 e9 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d be fb 2a 00 f7 d8 64 89 01 48
RSP: 002b:00007ffc55baaab8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e9
RAX: ffffffffffffffda RBX: 00007ffc55baabb0 RCX: 00007f4c9156b2aa
RDX: 000000000000000e RSI: 0000000000000001 RDI: 0000000000000004
RBP: 0000563a0bb07028 R08: 0000000000000020 R09: 0000000000000018
R10: 00007ffc55baab64 R11: 0000000000000246 R12: 0000563a0bb07010
R13: 0000563a0bb080c0 R14: 0000000000000003 R15: 000000000000000e
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/20 16:53 upstream 4d02da974ea8 68068804 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.