syzbot


KCSAN: data-race in get_signal / ptrace_attach (4)

Status: auto-closed as invalid on 2021/10/19 11:18
Reported-by: syzbot+@syzkaller.appspotmail.com
First crash: 438d, last: 438d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in get_signal / ptrace_attach (2) 1 879d 879d 0/24 auto-closed as invalid on 2020/08/04 00:25
upstream KCSAN: data-race in get_signal / ptrace_attach (5) 1 283d 283d 0/24 auto-closed as invalid on 2022/03/23 02:38
upstream KCSAN: data-race in get_signal / ptrace_attach (3) 1 570d 570d 0/24 auto-closed as invalid on 2021/06/09 02:47
upstream KCSAN: data-race in get_signal / ptrace_attach 1 1114d 1114d 0/24 closed as invalid on 2019/11/19 14:04

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

write to 0xffff8881390d4030 of 4 bytes by task 13900 on cpu 0:
 ptrace_attach+0x243/0x510 kernel/ptrace.c:424
 __do_sys_ptrace kernel/ptrace.c:1297 [inline]
 __se_sys_ptrace+0xc1/0x1b0 kernel/ptrace.c:1277
 __x64_sys_ptrace+0x51/0x60 kernel/ptrace.c:1277
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881390d4030 of 4 bytes by task 13899 on cpu 1:
 get_signal+0x713/0x15d0 kernel/signal.c:2755
 arch_do_signal_or_restart+0x8c/0x280 arch/x86/kernel/signal.c:865
 handle_signal_work kernel/entry/common.c:148 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
 exit_to_user_mode_prepare+0x109/0x190 kernel/entry/common.c:209
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:315
 irqentry_exit+0xe/0x30 kernel/entry/common.c:406
 asm_exc_page_fault+0x1e/0x30

value changed: 0x00000000 -> 0x00010001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 13899 Comm: syz-executor.4 Not tainted 5.15.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-upstream-kcsan-gce 2021/09/14 11:08 upstream d0ee23f9d78b 58d09404 .config log report info KCSAN: data-race in get_signal / ptrace_attach
* Struck through repros no longer work on HEAD.