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BUG: KCSAN: data-race in mlock_new_folio / need_mlock_drain

read-write to 0xffff888237d26a10 of 1 bytes by task 8547 on cpu 1:
 folio_batch_add include/linux/pagevec.h:77 [inline]
 mlock_new_folio+0x114/0x200 mm/mlock.c:280
 folio_add_lru_vma+0x5f/0x70 mm/swap.c:522
 do_anonymous_page mm/memory.c:5118 [inline]
 do_pte_missing mm/memory.c:4249 [inline]
 handle_pte_fault mm/memory.c:6069 [inline]
 __handle_mm_fault mm/memory.c:6212 [inline]
 handle_mm_fault+0x27e0/0x2be0 mm/memory.c:6381
 faultin_page mm/gup.c:1186 [inline]
 __get_user_pages+0x1036/0x1fb0 mm/gup.c:1488
 populate_vma_page_range mm/gup.c:1926 [inline]
 __mm_populate+0x243/0x3a0 mm/gup.c:2029
 mm_populate include/linux/mm.h:3348 [inline]
 do_mremap mm/mremap.c:1733 [inline]
 __do_sys_mremap mm/mremap.c:1782 [inline]
 __se_sys_mremap+0x640/0x6f0 mm/mremap.c:1750
 __x64_sys_mremap+0x67/0x80 mm/mremap.c:1750
 x64_sys_call+0x2ba9/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:26
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d26a10 of 1 bytes by task 6213 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:779 [inline]
 __lru_add_drain_all+0x220/0x3f0 mm/swap.c:867
 lru_add_drain_all+0x10/0x20 mm/swap.c:883
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 ext4_put_super+0x624/0x7d0 fs/ext4/super.c:1339
 generic_shutdown_super+0xe6/0x210 fs/super.c:643
 kill_block_super+0x2a/0x70 fs/super.c:1755
 ext4_kill_sb+0x42/0x80 fs/ext4/super.c:7391
 deactivate_locked_super+0x75/0x1c0 fs/super.c:474
 deactivate_super+0x97/0xa0 fs/super.c:507
 cleanup_mnt+0x269/0x2e0 fs/namespace.c:1417
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1424
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xe4/0x100 kernel/entry/common.c:114
 exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
 syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
 do_syscall_64+0x1d6/0x200 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x12 -> 0x14

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 6213 Comm: syz-executor Not tainted 6.16.0-rc5-syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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