[moderation] [mm?] KCSAN: data-race in try_to_migrate_one / vms_clear_ptes

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 63676eefb7a0 Merge tag 'sched_ext-for-6.13-rc5-fixes' of g..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bde418580000
kernel config: https://syzkaller.appspot.com/x/.config?x=c5e179f449c1ff36
dashboard link: https://syzkaller.appspot.com/bug?extid=084f9aaa4ceb59281277
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

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

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/867eb8fde4e1/disk-63676eef.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a4c43dfe0999/vmlinux-63676eef.xz
kernel image: https://storage.googleapis.com/syzbot-assets/9b651cd4799d/bzImage-63676eef.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+084f9a...@syzkaller.appspotmail.com

sit0 speed is unknown, defaulting to 1000
==================================================================
BUG: KCSAN: data-race in try_to_migrate_one / vms_clear_ptes

read to 0xffff888100057578 of 8 bytes by task 24105 on cpu 1:
update_hiwater_rss include/linux/mm.h:2667 [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:1328 [inline]
migrate_pages_batch+0x76a/0x1910 mm/migrate.c:1799
migrate_pages_sync mm/migrate.c:1965 [inline]
migrate_pages+0xff1/0x1820 mm/migrate.c:2074
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+0xf79/0x1160 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

write to 0xffff888100057578 of 8 bytes by task 24095 on cpu 0:
update_hiwater_rss include/linux/mm.h:2668 [inline]
vms_clear_ptes+0x1a7/0x300 mm/vma.c:1135
vms_clean_up_area mm/vma.c:1155 [inline]
__mmap_prepare mm/vma.c:2278 [inline]
__mmap_region+0x4fb/0x1400 mm/vma.c:2443
mmap_region+0x164/0x1e0 mm/mmap.c:1348
do_mmap+0x718/0xb60 mm/mmap.c:496
vm_mmap_pgoff+0x133/0x290 mm/util.c:580
ksys_mmap_pgoff+0xd0/0x330 mm/mmap.c:542
x64_sys_call+0x1940/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:10
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: 0x0000000000001c85 -> 0x0000000000001ca5

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 24095 Comm: syz.7.6398 Not tainted 6.13.0-rc5-syzkaller-00161-g63676eefb7a0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.