syzbot

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BUG: KCSAN: data-race in mlock_folio_batch / need_mlock_drain

write to 0xffff888237d29f28 of 1 bytes by task 28244 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:625 [inline]
 page_remove_rmap+0x1fe/0x2b0 mm/rmap.c:1466
 zap_pte_range mm/memory.c:1456 [inline]
 zap_pmd_range mm/memory.c:1573 [inline]
 zap_pud_range mm/memory.c:1602 [inline]
 zap_p4d_range mm/memory.c:1623 [inline]
 unmap_page_range+0xd3f/0x1db0 mm/memory.c:1644
 unmap_single_vma+0x142/0x1d0 mm/memory.c:1690
 unmap_vmas+0xf6/0x1a0 mm/memory.c:1731
 exit_mmap+0x167/0x640 mm/mmap.c:3210
 __mmput+0x28/0x1c0 kernel/fork.c:1349
 mmput+0x4c/0x60 kernel/fork.c:1371
 exit_mm+0xe3/0x180 kernel/exit.c:567
 do_exit+0x580/0x1660 kernel/exit.c:861
 do_group_exit+0x101/0x150 kernel/exit.c:1024
 get_signal+0xf3c/0x1090 kernel/signal.c:2892
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:309
 exit_to_user_mode_loop+0x6f/0xe0 kernel/entry/common.c:168
 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+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff888237d29f28 of 1 bytes by task 3091 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/0x7d0 fs/ext4/super.c:1353
 generic_shutdown_super+0xdb/0x210 fs/super.c:693
 kill_block_super+0x2a/0x60 fs/super.c:1646
 ext4_kill_sb+0x44/0x80 fs/ext4/super.c:7305
 deactivate_locked_super+0x73/0x1c0 fs/super.c:481
 deactivate_super+0x9b/0xb0 fs/super.c:514
 cleanup_mnt+0x272/0x2e0 fs/namespace.c:1254
 __cleanup_mnt+0x19/0x20 fs/namespace.c:1261
 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+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0f -> 0x0a

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3091 Comm: syz-executor.1 Not tainted 6.6.0-rc5-syzkaller-00067-g8182d7a3f1b8 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/06/2023
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EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.
EXT4-fs (loop1): unmounting filesystem 00000000-0000-0000-0000-000000000000.