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KCSAN: data-race in do_semtimedop / do_semtimedop

Status: closed as invalid on 2020/06/18 14:13
Subsystems: kernel
[Documentation on labels]
First crash: 1410d, last: 1410d

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

write to 0xffff8880b2612ac0 of 4 bytes by task 21148 on cpu 0:
 complexmode_enter ipc/sem.c:345 [inline]
 sem_lock ipc/sem.c:397 [inline]
 sem_lock ipc/sem.c:386 [inline]
 do_semtimedop+0x269c/0x26e0 ipc/sem.c:2083
 __do_sys_semop ipc/sem.c:2278 [inline]
 __se_sys_semop ipc/sem.c:2275 [inline]
 __x64_sys_semop+0x49/0x60 ipc/sem.c:2275
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff8880b2612ac0 of 4 bytes by task 21145 on cpu 1:
 sem_lock ipc/sem.c:415 [inline]
 do_semtimedop+0x574/0x26e0 ipc/sem.c:2083
 __do_sys_semop ipc/sem.c:2278 [inline]
 __se_sys_semop ipc/sem.c:2275 [inline]
 __x64_sys_semop+0x49/0x60 ipc/sem.c:2275
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 21145 Comm: syz-executor.5 Not tainted 5.7.0-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: 1 PID: 21145 Comm: syz-executor.5 Not tainted 5.7.0-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+0x11d/0x187 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0x1a kernel/kcsan/report.c:626
 kcsan_setup_watchpoint+0x3fb/0x440 kernel/kcsan/core.c:519
 sem_lock ipc/sem.c:415 [inline]
 do_semtimedop+0x574/0x26e0 ipc/sem.c:2083
 __do_sys_semop ipc/sem.c:2278 [inline]
 __se_sys_semop ipc/sem.c:2275 [inline]
 __x64_sys_semop+0x49/0x60 ipc/sem.c:2275
 do_syscall_64+0xc7/0x3b0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45ca69
Code: 0d b7 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f043866ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000041
RAX: ffffffffffffffda RBX: 00000000004fc500 RCX: 000000000045ca69
RDX: 0000000000000001 RSI: 00000000200001c0 RDI: 0000000000000006
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000008da R14: 00000000004cba45 R15: 00007f043866f6d4
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
2020/06/08 11:32 https://github.com/google/ktsan.git kcsan 7c3cd68e5d38 7604bb03 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.