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

Status: auto-closed as invalid on 2020/12/04 12:11
Subsystems: fs
[Documentation on labels]
First crash: 1270d, last: 1265d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl fs 1 1637d 1637d 0/26 closed as invalid on 2019/11/19 13:44
upstream KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (3) fs 1 1508d 1508d 0/26 auto-closed as invalid on 2020/05/10 10:19
upstream KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (6) fs 1 1227d 1227d 0/26 auto-closed as invalid on 2021/01/11 23:50
upstream KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (4) fs 1 1317d 1317d 0/26 auto-closed as invalid on 2020/10/14 02:21
upstream KCSAN: data-race in userfaultfd_ioctl / userfaultfd_ioctl (2) fs 1 1606d 1606d 0/26 closed as invalid on 2020/01/09 14:13

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

write to 0xffff888018f6b7f0 of 4 bytes by task 24109 on cpu 1:
 userfaultfd_api fs/userfaultfd.c:1858 [inline]
 userfaultfd_ioctl+0x853/0x24e0 fs/userfaultfd.c:1882
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888018f6b7f0 of 4 bytes by task 24114 on cpu 0:
 userfaultfd_ioctl+0x8f/0x24e0 fs/userfaultfd.c:1877
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 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: 24114 Comm: syz-executor.0 Not tainted 5.10.0-rc1-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: 24114 Comm: syz-executor.0 Not tainted 5.10.0-rc1-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
 userfaultfd_ioctl+0x8f/0x24e0 fs/userfaultfd.c:1877
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl+0xcb/0x140 fs/ioctl.c:739
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:739
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f302f278c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000001a8c0 RCX: 000000000045deb9
RDX: 0000000020000000 RSI: 00000000c020aa00 RDI: 0000000000000003
RBP: 000000000118c158 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118c124
R13: 00007ffced62966f R14: 00007f302f2799c0 R15: 000000000118c124
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/10/30 12:11 upstream 07e088730245 a6e3ac3b .config console log report info ci2-upstream-kcsan-gce
2020/10/25 19:36 upstream 986b9eacb259 a1839e81 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.