linux-kernel - [syzbot] [mm?] KCSAN: data-race in mprotect_fixup / try_to_migrate

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Message-ID: <67a34e60.050a0220.50516.0040.GAE@google.com>
Date: Wed, 05 Feb 2025 03:41:20 -0800
From: syzbot <syzbot+c2e5712cbb14c95d4847@...kaller.appspotmail.com>
To: Liam.Howlett@...cle.com, akpm@...ux-foundation.org, jannh@...gle.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, lorenzo.stoakes@...cle.com, 
	syzkaller-bugs@...glegroups.com, vbabka@...e.cz
Subject: [syzbot] [mm?] KCSAN: data-race in mprotect_fixup / try_to_migrate_one

Hello,

syzbot found the following issue on:

HEAD commit:    d009de7d5428 Merge tag 'livepatching-for-6.14-rc2' of git:..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12b678a4580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=9e757e3762bd630b
dashboard link: https://syzkaller.appspot.com/bug?extid=c2e5712cbb14c95d4847
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/9235000a1b88/disk-d009de7d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/098ef82f8ab3/vmlinux-d009de7d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/4f51f5eb5782/bzImage-d009de7d.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c2e5712cbb14c95d4847@...kaller.appspotmail.com

==================================================================
BUG: KCSAN: data-race in mprotect_fixup / try_to_migrate_one

write to 0xffff888114b41700 of 8 bytes by task 6432 on cpu 1:
 vm_flags_init include/linux/mm.h:875 [inline]
 vm_flags_reset include/linux/mm.h:887 [inline]
 mprotect_fixup+0x419/0x5e0 mm/mprotect.c:679
 do_mprotect_pkey+0x6cc/0x9a0 mm/mprotect.c:840
 __do_sys_mprotect mm/mprotect.c:861 [inline]
 __se_sys_mprotect mm/mprotect.c:858 [inline]
 __x64_sys_mprotect+0x48/0x60 mm/mprotect.c:858
 x64_sys_call+0x2770/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:11
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888114b41700 of 8 bytes by task 6418 on cpu 0:
 try_to_migrate_one+0xb5a/0x12e0 mm/rmap.c:2321
 rmap_walk_anon+0x28f/0x440 mm/rmap.c:2646
 try_to_migrate+0x11f/0x150
 migrate_folio_unmap mm/migrate.c:1320 [inline]
 migrate_pages_batch+0x786/0x1930 mm/migrate.c:1866
 migrate_pages_sync mm/migrate.c:1989 [inline]
 migrate_pages+0xf02/0x1840 mm/migrate.c:2098
 do_mbind mm/mempolicy.c:1394 [inline]
 kernel_mbind mm/mempolicy.c:1537 [inline]
 __do_sys_mbind mm/mempolicy.c:1611 [inline]
 __se_sys_mbind+0xfd1/0x11c0 mm/mempolicy.c:1607
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1607
 x64_sys_call+0x2662/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:238
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000102077 -> 0x0000000000102071

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6418 Comm: syz.0.1339 Not tainted 6.14.0-rc1-syzkaller-00026-gd009de7d5428 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================


---
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