syzbot

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BUG: KCSAN: data-race in mlock_folio_batch / need_mlock_drain

write to 0xffff888237d29f28 of 1 bytes by task 8826 on cpu 1:
 folio_batch_reinit include/linux/pagevec.h:48 [inline]
 mlock_folio_batch+0x1935/0x1950 mm/mlock.c:210
 munlock_folio+0xbd/0x120 mm/mlock.c:304
 munlock_vma_folio mm/internal.h:687 [inline]
 page_remove_rmap+0x1b8/0x260 mm/rmap.c:1508
 zap_pte_range mm/memory.c:1465 [inline]
 zap_pmd_range mm/memory.c:1583 [inline]
 zap_pud_range mm/memory.c:1612 [inline]
 zap_p4d_range mm/memory.c:1633 [inline]
 unmap_page_range+0xdb6/0x1cd0 mm/memory.c:1654
 unmap_single_vma+0x142/0x1d0 mm/memory.c:1700
 unmap_vmas+0x18d/0x280 mm/memory.c:1744
 exit_mmap+0x167/0x640 mm/mmap.c:3308
 __mmput+0x28/0x1c0 kernel/fork.c:1349
 mmput+0x4c/0x60 kernel/fork.c:1371
 exit_mm+0xe3/0x180 kernel/exit.c:567
 do_exit+0x585/0x16d0 kernel/exit.c:856
 do_group_exit+0x141/0x150 kernel/exit.c:1018
 __do_sys_exit_group kernel/exit.c:1029 [inline]
 __se_sys_exit_group kernel/exit.c:1027 [inline]
 __x64_sys_exit_group+0x1f/0x20 kernel/exit.c:1027
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

read to 0xffff888237d29f28 of 1 bytes by task 3141 on cpu 0:
 folio_batch_count include/linux/pagevec.h:53 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:236
 cpu_needs_drain mm/swap.c:801 [inline]
 __lru_add_drain_all+0x240/0x420 mm/swap.c:889
 lru_add_drain_all+0x10/0x20 mm/swap.c:905
 invalidate_bdev+0x54/0x70 block/bdev.c:86
 ext4_put_super+0x51b/0x7e0 fs/ext4/super.c:1361
 generic_shutdown_super+0xdb/0x210 fs/super.c:696
 kill_block_super+0x2a/0x60 fs/super.c:1667
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7330
 deactivate_locked_super+0x7a/0x1c0 fs/super.c:484
 deactivate_super+0x9b/0xb0 fs/super.c:517
 cleanup_mnt+0x272/0x2e0 fs/namespace.c:1256
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1263
 task_work_run+0x135/0x1a0 kernel/task_work.c:180
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xd6/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6c/0xb0 kernel/entry/common.c:204
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x50/0x110 arch/x86/entry/common.c:89
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

value changed: 0x0f -> 0x01

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3141 Comm: syz-executor.0 Not tainted 6.7.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop0): unmounting filesystem 00000000-0000-0000-0000-000000000000.