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KCSAN: data-race in get_signal / ptrace_attach (7)

Status: auto-obsoleted due to no activity on 2025/03/02 06:49
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+e0175d320ca12ab5f0f3@syzkaller.appspotmail.com
First crash: 338d, last: 338d
▶ ▼ Similar bugs (7)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in get_signal / ptrace_attach (2) kasan 6 1 1989d 1989d 0/29 auto-closed as invalid on 2020/08/04 00:25
upstream KCSAN: data-race in get_signal / ptrace_attach (8) kernel 6 1 15d 15d 0/29 moderation: reported on 2025/11/24 19:14
upstream KCSAN: data-race in get_signal / ptrace_attach (5) kernel 6 1 1392d 1392d 0/29 auto-closed as invalid on 2022/03/23 02:38
upstream KCSAN: data-race in get_signal / ptrace_attach (3) kernel 6 1 1679d 1679d 0/29 auto-closed as invalid on 2021/06/09 02:47
upstream KCSAN: data-race in get_signal / ptrace_attach (6) kernel 6 1 649d 649d 0/29 auto-obsoleted due to no activity on 2024/04/04 22:16
upstream KCSAN: data-race in get_signal / ptrace_attach (4) kernel 6 1 1547d 1547d 0/29 auto-closed as invalid on 2021/10/19 11:18
upstream KCSAN: data-race in get_signal / ptrace_attach kasan 6 1 2223d 2223d 0/29 closed as invalid on 2019/11/19 14:04

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

write to 0xffff88815d1fa130 of 4 bytes by task 19659 on cpu 0:
 ptrace_attach+0x258/0x520 kernel/ptrace.c:462
 __do_sys_ptrace kernel/ptrace.c:1276 [inline]
 __se_sys_ptrace+0x149/0x2b0 kernel/ptrace.c:1258
 __x64_sys_ptrace+0x55/0x70 kernel/ptrace.c:1258
 x64_sys_call+0x2225/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:102
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88815d1fa130 of 4 bytes by task 19661 on cpu 1:
 get_signal+0x3a0/0x1000 kernel/signal.c:2902
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:337
 exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 irqentry_exit_to_user_mode+0xa7/0x120 kernel/entry/common.c:231
 irqentry_exit+0x12/0x50 kernel/entry/common.c:334
 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623

value changed: 0x00000000 -> 0x00000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 19661 Comm: syz.1.5127 Not tainted 6.13.0-rc5-syzkaller-00163-gab75170520d4 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/05 06:49 upstream ab75170520d4 f3558dbf .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in get_signal / ptrace_attach
* Struck through repros no longer work on HEAD.