syzbot


KCSAN: data-race in copy_mm / copy_page_range

Status: upstream: reported on 2025/04/28 09:27
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+cfd78ff95994c614d233@syzkaller.appspotmail.com
First crash: 2d01h, last: 2d01h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] KCSAN: data-race in copy_mm / copy_page_range 0 (1) 2025/04/28 09:27

Sample crash report:
==================================================================
BUG: KCSAN: data-race in copy_mm / copy_page_range

write to 0xffff88810a1bc868 of 8 bytes by task 15516 on cpu 0:
 __list_add include/linux/list.h:153 [inline]
 list_add include/linux/list.h:169 [inline]
 copy_nonpresent_pte mm/memory.c:803 [inline]
 copy_pte_range mm/memory.c:1143 [inline]
 copy_pmd_range mm/memory.c:1255 [inline]
 copy_pud_range mm/memory.c:1292 [inline]
 copy_p4d_range mm/memory.c:1316 [inline]
 copy_page_range+0x2525/0x3760 mm/memory.c:1410
 dup_mmap kernel/fork.c:726 [inline]
 dup_mm kernel/fork.c:1734 [inline]
 copy_mm+0xab6/0x1310 kernel/fork.c:1786
 copy_process+0xcf1/0x1f90 kernel/fork.c:2429
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2844
 __do_sys_clone kernel/fork.c:2987 [inline]
 __se_sys_clone kernel/fork.c:2971 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2971
 x64_sys_call+0x2c59/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:57
 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 0xffff88810a1bc780 of 1344 bytes by task 12894 on cpu 1:
 dup_mm kernel/fork.c:1728 [inline]
 copy_mm+0xfb/0x1310 kernel/fork.c:1786
 copy_process+0xcf1/0x1f90 kernel/fork.c:2429
 kernel_clone+0x16c/0x5b0 kernel/fork.c:2844
 __do_sys_clone kernel/fork.c:2987 [inline]
 __se_sys_clone kernel/fork.c:2971 [inline]
 __x64_sys_clone+0xe6/0x120 kernel/fork.c:2971
 x64_sys_call+0x2c59/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:57
 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

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 12894 Comm: syz-executor Not tainted 6.15.0-rc3-syzkaller-00342-g5bc1018675ec #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/04/27 18:09 upstream 5bc1018675ec c6b4fb39 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-kcsan-gce KCSAN: data-race in copy_mm / copy_page_range
* Struck through repros no longer work on HEAD.