syzbot


KCSAN: data-race in copy_fs / free_bprm (2)

Status: moderation: reported on 2025/12/08 23:21
Subsystems: mm fs
[Documentation on labels]
Reported-by: syzbot+7b74f290c756a4300d71@syzkaller.appspotmail.com
First crash: 3d22h, last: 3d22h
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KCSAN: data-race in copy_fs / free_bprm fs mm 6 1 219d 219d 0/29 auto-obsoleted due to no activity on 2025/07/02 10:34

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

write to 0xffff888104fa4410 of 4 bytes by task 14168 on cpu 0:
 free_bprm+0x122/0x220 fs/exec.c:1389
 do_execveat_common+0x560/0x750 fs/exec.c:1861
 do_execveat fs/exec.c:1944 [inline]
 __do_sys_execveat fs/exec.c:2018 [inline]
 __se_sys_execveat fs/exec.c:2012 [inline]
 __x64_sys_execveat+0x73/0x90 fs/exec.c:2012
 x64_sys_call+0x1c0e/0x3000 arch/x86/include/generated/asm/syscalls_64.h:323
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888104fa4410 of 4 bytes by task 14167 on cpu 1:
 copy_fs+0x90/0xf0 kernel/fork.c:1599
 copy_process+0xc3f/0x1ef0 kernel/fork.c:2212
 kernel_clone+0x16c/0x5c0 kernel/fork.c:2651
 __do_sys_clone3 kernel/fork.c:2953 [inline]
 __se_sys_clone3+0x1c2/0x200 kernel/fork.c:2932
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:2932
 x64_sys_call+0x2c0f/0x3000 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd8/0x2a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000001 -> 0x00000000

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 14167 Comm: syz.7.14810 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/08 23:20 upstream c2f2b01b74be d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_fs / free_bprm
* Struck through repros no longer work on HEAD.