syzbot


KCSAN: data-race in mlock_fixup / try_to_unmap_one

Status: auto-closed as invalid on 2020/12/21 12:01
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+dad5f9bc93610bf74a13@syzkaller.appspotmail.com
First crash: 1258d, last: 1258d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in mlock_fixup / try_to_unmap_one (2) mm 1 1101d 1095d 0/26 auto-closed as invalid on 2021/05/26 00:24

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

write to 0xffff88810b7c55c8 of 8 bytes by task 29773 on cpu 0:
 mlock_fixup+0x2a2/0x390 mm/mlock.c:579
 apply_mlockall_flags+0x1cd/0x220 mm/mlock.c:797
 __do_sys_mlockall mm/mlock.c:825 [inline]
 __se_sys_mlockall+0x187/0x250 mm/mlock.c:804
 __x64_sys_mlockall+0x1b/0x20 mm/mlock.c:804
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88810b7c55c8 of 8 bytes by task 29761 on cpu 1:
 try_to_unmap_one+0xb2/0x1720 mm/rmap.c:1389
 rmap_walk_file+0x260/0x4f0 mm/rmap.c:1933
 rmap_walk mm/rmap.c:1951 [inline]
 try_to_munlock+0xe7/0x150 mm/rmap.c:1802
 __munlock_isolated_page mm/mlock.c:141 [inline]
 __munlock_pagevec+0x57d/0x830 mm/mlock.c:351
 munlock_vma_pages_range+0x581/0x760 mm/mlock.c:504
 munlock_vma_pages_all mm/internal.h:342 [inline]
 exit_mmap+0x128/0x3b0 mm/mmap.c:3206
 __mmput+0xa2/0x220 kernel/fork.c:1079
 mmput+0x38/0x40 kernel/fork.c:1100
 exit_mm+0x307/0x370 kernel/exit.c:486
 do_exit+0x3c2/0x15a0 kernel/exit.c:796
 do_group_exit+0x16f/0x170 kernel/exit.c:906
 __do_sys_exit_group+0xb/0x10 kernel/exit.c:917
 __se_sys_exit_group+0x5/0x10 kernel/exit.c:915
 __x64_sys_exit_group+0x16/0x20 kernel/exit.c:915
 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: 1 PID: 29761 Comm: syz-executor.5 Not tainted 5.10.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/14 10:16 upstream 9e6a39eae450 1bf9a662 .config console log report info ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.