linux-kernel - [syzbot] [kernel?] KCSAN: data-race in copy_mm / copy_page

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Message-ID: <680f4a00.050a0220.2b69d1.032a.GAE@google.com>
Date: Mon, 28 Apr 2025 02:27:28 -0700
From: syzbot <syzbot+cfd78ff95994c614d233@...kaller.appspotmail.com>
To: linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [kernel?] KCSAN: data-race in copy_mm / copy_page_range

Hello,

syzbot found the following issue on:

HEAD commit:    5bc1018675ec Merge tag 'pci-v6.15-fixes-3' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=152930d4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=fc7049672597c030
dashboard link: https://syzkaller.appspot.com/bug?extid=cfd78ff95994c614d233
compiler:       Debian clang version 20.1.2 (++20250402124445+58df0ef89dd6-1~exp1~20250402004600.97), Debian LLD 20.1.2

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/b07ed9969a13/disk-5bc10186.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/3abab03798d3/vmlinux-5bc10186.xz
kernel image: https://storage.googleapis.com/syzbot-assets/8fca26b1845c/bzImage-5bc10186.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+cfd78ff95994c614d233@...kaller.appspotmail.com

==================================================================
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
==================================================================


---
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