syzbot


KCSAN: data-race in futex_wait_queue_me / oom_badness

Status: auto-closed as invalid on 2020/04/01 22:00
Subsystems: mm
[Documentation on labels]
First crash: 2039d, last: 2039d

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

read to 0xffff8880b3f5e024 of 4 bytes by task 15001 on cpu 1:
 oom_unkillable_task mm/oom_kill.c:165 [inline]
 oom_badness+0x52/0xa0 mm/oom_kill.c:203
 proc_oom_score+0x70/0xc0 fs/proc/base.c:553
 proc_single_show+0x92/0x120 fs/proc/base.c:756
 seq_read+0x350/0x9d0 fs/seq_file.c:229
 do_loop_readv_writev fs/read_write.c:714 [inline]
 do_loop_readv_writev fs/read_write.c:701 [inline]
 do_iter_read+0x357/0x3d0 fs/read_write.c:935
 vfs_readv+0x9c/0xf0 fs/read_write.c:997
 do_preadv+0x131/0x1d0 fs/read_write.c:1089
 __do_sys_preadv fs/read_write.c:1139 [inline]
 __se_sys_preadv fs/read_write.c:1134 [inline]
 __x64_sys_preadv+0x61/0x80 fs/read_write.c:1134
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff8880b3f5e024 of 4 bytes by task 14999 on cpu 0:
 freezer_do_not_count include/linux/freezer.h:109 [inline]
 freezable_schedule include/linux/freezer.h:171 [inline]
 futex_wait_queue_me+0x17d/0x290 kernel/futex.c:2704
 futex_wait+0x19b/0x3f0 kernel/futex.c:2810
 do_futex+0xe9/0x18d0 kernel/futex.c:3881
 __do_sys_futex kernel/futex.c:3942 [inline]
 __se_sys_futex kernel/futex.c:3910 [inline]
 __x64_sys_futex+0x2cd/0x3f0 kernel/futex.c:3910
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 14999 Comm: syz-executor.5 Not tainted 5.5.0-rc1-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
2020/01/22 21:59 https://github.com/google/ktsan.git kcsan 245a43005292 3334d684 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.