[moderation] [mm?] KCSAN: data-race in folios_put_refs / need_mlock_drain

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 14d7c92f8df9 Revert "mm: mmap: allow for the maximum numbe..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=135d2fca980000
kernel config: https://syzkaller.appspot.com/x/.config?x=cd45aedbb3f7637b
dashboard link: https://syzkaller.appspot.com/bug?extid=7f97e2bd338da740913e
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/126222ab61b9/disk-14d7c92f.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48cd219f1291/vmlinux-14d7c92f.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2216ce34df10/bzImage-14d7c92f.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7f97e2...@syzkaller.appspotmail.com

EXT4-fs (loop4): unmounting filesystem 00000000-0000-0000-0000-000000000000.
==================================================================
BUG: KCSAN: data-race in folios_put_refs / need_mlock_drain

write to 0xffff888237d2b410 of 1 bytes by task 13199 on cpu 1:
folio_batch_reinit include/linux/pagevec.h:50 [inline]
folios_put_refs+0x266/0x2b0 mm/swap.c:1018
folios_put include/linux/mm.h:1567 [inline]
mlock_folio_batch+0x192a/0x1940 mm/mlock.c:209
mlock_new_folio+0x1a3/0x200 mm/mlock.c:282
folio_add_lru_vma+0x15d/0x170 mm/swap.c:540
do_anonymous_page mm/memory.c:4505 [inline]
do_pte_missing mm/memory.c:3895 [inline]
handle_pte_fault mm/memory.c:5380 [inline]
__handle_mm_fault mm/memory.c:5523 [inline]
handle_mm_fault+0x2411/0x2a80 mm/memory.c:5688
faultin_page mm/gup.c:1290 [inline]
__get_user_pages+0x49d/0xf10 mm/gup.c:1589
populate_vma_page_range mm/gup.c:2029 [inline]
__mm_populate+0x25b/0x3b0 mm/gup.c:2132
mm_populate include/linux/mm.h:3464 [inline]
__do_sys_mremap mm/mremap.c:1200 [inline]
__se_sys_mremap+0x960/0xf20 mm/mremap.c:993
__x64_sys_mremap+0x67/0x80 mm/mremap.c:993
x64_sys_call+0x1029/0x2d70 arch/x86/include/generated/asm/syscalls_64.h:26
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 0xffff888237d2b410 of 1 bytes by task 12910 on cpu 0:
folio_batch_count include/linux/pagevec.h:56 [inline]
need_mlock_drain+0x30/0x50 mm/mlock.c:235
cpu_needs_drain mm/swap.c:806 [inline]
__lru_add_drain_all+0x235/0x410 mm/swap.c:894
lru_add_drain_all+0x10/0x20 mm/swap.c:910
invalidate_bdev+0x47/0x70 block/bdev.c:100
ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1345
generic_shutdown_super+0xde/0x210 fs/super.c:642
kill_block_super+0x2a/0x70 fs/super.c:1676
ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7301
deactivate_locked_super+0x7d/0x1c0 fs/super.c:473
deactivate_super+0x9f/0xb0 fs/super.c:506
cleanup_mnt+0x268/0x2e0 fs/namespace.c:1267
__cleanup_mnt+0x19/0x20 fs/namespace.c:1274
task_work_run+0x13a/0x1a0 kernel/task_work.c:180
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xbe/0x130 kernel/entry/common.c:218
do_syscall_64+0xd6/0x1c0 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x1f -> 0x04

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12910 Comm: syz-executor.4 Not tainted 6.10.0-rc4-syzkaller-00033-g14d7c92f8df9 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

If the report is already addressed, let syzbot know by replying with:
#syz fix: exact-commit-title

If you want to overwrite report's subsystems, reply with:
#syz set subsystems: new-subsystem
(See the list of subsystem names on the web dashboard)

If the report is a duplicate of another one, reply with:
#syz dup: exact-subject-of-another-report

If you want to undo deduplication, reply with:
#syz undup