syzbot


KCSAN: data-race in copy_fs / free_bprm

Status: upstream: reported on 2025/05/07 12:54
Subsystems: fs mm
[Documentation on labels]
Reported-by: syzbot+2428028ccd7d1ff933a0@syzkaller.appspotmail.com
First crash: 1d04h, last: 1d04h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fs?] [mm?] KCSAN: data-race in copy_fs / free_bprm 0 (1) 2025/05/07 12:54

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

write to 0xffff88810475a110 of 4 bytes by task 10717 on cpu 0:
 free_bprm+0x122/0x220 fs/exec.c:1498
 do_execveat_common+0x560/0x750 fs/exec.c:1970
 do_execveat fs/exec.c:2053 [inline]
 __do_sys_execveat fs/exec.c:2127 [inline]
 __se_sys_execveat fs/exec.c:2121 [inline]
 __x64_sys_execveat+0x73/0x90 fs/exec.c:2121
 x64_sys_call+0x2dae/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:323
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff88810475a110 of 4 bytes by task 10715 on cpu 1:
 copy_fs+0x90/0xf0 kernel/fork.c:1804
 copy_process+0xc6e/0x1f90 kernel/fork.c:2420
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2844
 __do_sys_clone3 kernel/fork.c:3148 [inline]
 __se_sys_clone3+0x1c2/0x200 kernel/fork.c:3127
 __x64_sys_clone3+0x31/0x40 kernel/fork.c:3127
 x64_sys_call+0x10c9/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:436
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 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: 10715 Comm: syz.5.2513 Not tainted 6.15.0-rc5-syzkaller-00032-g0d8d44db295c #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/19/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/05/07 10:33 upstream 0d8d44db295c 350f4ffc .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.