EXT4-fs warning (device loop7): ext4_init_metadata_csum:4685: metadata_csum and uninit_bg are redundant flags; please run fsck.
EXT4-fs (loop7): VFS: Found ext4 filesystem with invalid superblock checksum.  Run e2fsck?
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BUG: KCSAN: data-race in mlock_folio / need_mlock_drain

read-write to 0xffff888237c27088 of 1 bytes by task 11138 on cpu 0:
 folio_batch_add include/linux/folio_batch.h:77 [inline]
 mlock_folio+0x14d/0x240 mm/mlock.c:257
 mlock_vma_folio mm/internal.h:1198 [inline]
 __folio_add_file_rmap mm/rmap.c:1715 [inline]
 folio_add_file_rmap_ptes+0x1d0/0x1e0 mm/rmap.c:1732
 set_pte_range+0x2c1/0x4f0 mm/memory.c:5586
 filemap_map_order0_folio mm/filemap.c:3880 [inline]
 filemap_map_pages+0x579/0xef0 mm/filemap.c:3950
 do_fault_around mm/memory.c:5818 [inline]
 do_read_fault mm/memory.c:5851 [inline]
 do_fault mm/memory.c:5994 [inline]
 do_pte_missing mm/memory.c:4566 [inline]
 handle_pte_fault mm/memory.c:6379 [inline]
 __handle_mm_fault mm/memory.c:6517 [inline]
 handle_mm_fault+0x14c5/0x2da0 mm/memory.c:6686
 faultin_page mm/gup.c:1126 [inline]
 __get_user_pages+0x129c/0x1f10 mm/gup.c:1428
 populate_vma_page_range mm/gup.c:1860 [inline]
 __mm_populate+0x242/0x390 mm/gup.c:1963
 mm_populate include/linux/mm.h:4171 [inline]
 __do_sys_mlockall mm/mlock.c:775 [inline]
 __se_sys_mlockall+0x35e/0x3c0 mm/mlock.c:751
 __x64_sys_mlockall+0x1f/0x30 mm/mlock.c:751
 x64_sys_call+0xf90/0x3020 arch/x86/include/generated/asm/syscalls_64.h:152
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c27088 of 1 bytes by task 11146 on cpu 1:
 folio_batch_count include/linux/folio_batch.h:56 [inline]
 need_mlock_drain+0x30/0x50 mm/mlock.c:235
 cpu_needs_drain mm/swap.c:837 [inline]
 __lru_add_drain_all+0x273/0x450 mm/swap.c:928
 lru_add_drain_all+0x10/0x20 mm/swap.c:944
 invalidate_bdev+0x47/0x70 block/bdev.c:101
 __ext4_fill_super fs/ext4/super.c:5803 [inline]
 ext4_fill_super+0x2c8c/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1640
 get_tree_bdev+0x1f/0x30 fs/super.c:1663
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1700
 fc_mount fs/namespace.c:1198 [inline]
 do_new_mount_fc fs/namespace.c:3765 [inline]
 do_new_mount+0x288/0x8d0 fs/namespace.c:3841
 path_mount+0x4ad/0xb90 fs/namespace.c:4161
 do_mount fs/namespace.c:4174 [inline]
 __do_sys_mount fs/namespace.c:4390 [inline]
 __se_sys_mount+0x28c/0x2e0 fs/namespace.c:4367
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4367
 x64_sys_call+0x2d61/0x3020 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x136/0x3c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x19 -> 0x1f

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 11146 Comm: syz.7.2196 Tainted: G        W           syzkaller #0 PREEMPT(lazy) 
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
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