linux-kernel - [syzbot] [mm?] KCSAN: data-race in try_to_migrate_one / vms_clear

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Message-ID: <67e3390c.050a0220.1ec46.0001.GAE@google.com>
Date: Tue, 25 Mar 2025 16:15:24 -0700
From: syzbot <syzbot+93107467480b9f9ed726@...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 try_to_migrate_one /
 vms_clear_ptes (2)

Hello,

syzbot found the following issue on:

HEAD commit:    3ba7dfb8da62 Merge tag 'rcu-next-v6.15' of git://git.kerne..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14254198580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=79f1cf4142160c34
dashboard link: https://syzkaller.appspot.com/bug?extid=93107467480b9f9ed726
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/dd40b872cca9/disk-3ba7dfb8.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/86a3a241fb7d/vmlinux-3ba7dfb8.xz
kernel image: https://storage.googleapis.com/syzbot-assets/1ce46917915c/bzImage-3ba7dfb8.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+93107467480b9f9ed726@...kaller.appspotmail.com

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

write to 0xffff88810005d8f8 of 8 bytes by task 8860 on cpu 1:
 update_hiwater_rss include/linux/mm.h:2675 [inline]
 vms_clear_ptes+0x1a2/0x300 mm/vma.c:1136
 vms_complete_munmap_vmas+0x17b/0x480 mm/vma.c:1186
 do_vmi_align_munmap+0x344/0x390 mm/vma.c:1445
 do_vmi_munmap+0x1eb/0x230 mm/vma.c:1493
 __vm_munmap+0x19a/0x280 mm/vma.c:2956
 __do_sys_munmap mm/mmap.c:1084 [inline]
 __se_sys_munmap mm/mmap.c:1081 [inline]
 __x64_sys_munmap+0x36/0x40 mm/mmap.c:1081
 x64_sys_call+0xe1b/0x2e10 arch/x86/include/generated/asm/syscalls_64.h:12
 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 0xffff88810005d8f8 of 8 bytes by task 8858 on cpu 0:
 update_hiwater_rss include/linux/mm.h:2674 [inline]
 try_to_migrate_one+0x775/0x12e0 mm/rmap.c:2183
 rmap_walk_anon+0x28f/0x440 mm/rmap.c:2646
 try_to_migrate+0x11f/0x150
 migrate_folio_unmap mm/migrate.c:1318 [inline]
 migrate_pages_batch+0x786/0x1930 mm/migrate.c:1864
 migrate_pages_sync mm/migrate.c:1987 [inline]
 migrate_pages+0xf02/0x1840 mm/migrate.c:2096
 do_mbind mm/mempolicy.c:1425 [inline]
 kernel_mbind mm/mempolicy.c:1568 [inline]
 __do_sys_mbind mm/mempolicy.c:1642 [inline]
 __se_sys_mbind+0xfd1/0x11c0 mm/mempolicy.c:1638
 __x64_sys_mbind+0x78/0x90 mm/mempolicy.c:1638
 x64_sys_call+0x13be/0x2e10 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: 0x0000000000001f8f -> 0x000000000000262f

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 8858 Comm: syz.2.1483 Tainted: G        W          6.14.0-syzkaller-00685-g3ba7dfb8da62 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
==================================================================


---
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