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KCSAN: data-race in __x64_sys_ptrace / ptrace_stop

Status: auto-closed as invalid on 2020/02/19 07:06
Subsystems: kasan
[Documentation on labels]
First crash: 1934d, last: 1925d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in __x64_sys_ptrace / ptrace_stop (2) kasan 60 1735d 1740d 0/28 auto-closed as invalid on 2020/07/23 08:53

Sample crash report:
==================================================================
BUG: KCSAN: data-race in __x64_sys_ptrace / ptrace_stop

write to 0xffff88809c585110 of 8 bytes by task 23035 on cpu 1:
 ptrace_stop+0x67/0x520 kernel/signal.c:2140
 ptrace_do_notify+0xed/0x120 kernel/signal.c:2263
 ptrace_notify+0x93/0xd0 kernel/signal.c:2273
 ptrace_report_syscall include/linux/tracehook.h:66 [inline]
 tracehook_report_syscall_entry include/linux/tracehook.h:104 [inline]
 syscall_trace_enter+0x4ce/0x740 arch/x86/entry/common.c:83
 do_syscall_64+0x29d/0x370 arch/x86/entry/common.c:286
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88809c585110 of 8 bytes by task 23040 on cpu 0:
 ptrace_unfreeze_traced kernel/ptrace.c:193 [inline]
 __do_sys_ptrace kernel/ptrace.c:1274 [inline]
 __se_sys_ptrace kernel/ptrace.c:1237 [inline]
 __x64_sys_ptrace+0x14c/0x220 kernel/ptrace.c:1237
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 23040 Comm: syz-executor.0 Not tainted 5.4.0-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: 0 PID: 23040 Comm: syz-executor.0 Not tainted 5.4.0-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/0x181 lib/dump_stack.c:118
 panic+0x210/0x640 kernel/panic.c:221
 kcsan_report.cold+0xc/0xd kernel/kcsan/report.c:315
 kcsan_setup_watchpoint+0x3fe/0x460 kernel/kcsan/core.c:423
 check_access kernel/kcsan/core.c:466 [inline]
 __tsan_read8 kernel/kcsan/core.c:596 [inline]
 __tsan_read8+0xc6/0x100 kernel/kcsan/core.c:596
 ptrace_unfreeze_traced kernel/ptrace.c:193 [inline]
 __do_sys_ptrace kernel/ptrace.c:1274 [inline]
 __se_sys_ptrace kernel/ptrace.c:1237 [inline]
 __x64_sys_ptrace+0x14c/0x220 kernel/ptrace.c:1237
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a849
Code: ad b6 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 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f2425e25c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000065
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000045a849
RDX: 0000000000000000 RSI: 00000000000001b7 RDI: 0000000000000018
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f2425e266d4
R13: 00000000004c8c5e R14: 00000000004e0380 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/12/11 07:05 https://github.com/google/ktsan.git kcsan ef798c30ba4e 101194eb .config console log report ci2-upstream-kcsan-gce
2019/12/02 16:49 https://github.com/google/ktsan.git kcsan ef798c30ba4e f879db37 .config console log report ci2-upstream-kcsan-gce
* Struck through repros no longer work on HEAD.