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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d275e0 of 8 bytes by task 15579 on cpu 1:
 bh_lru_install fs/buffer.c:1323 [inline]
 find_get_block_common+0x45c/0x870 fs/buffer.c:1388
 bdev_getblk+0x4c/0x3c0 include/linux/gfp.h:-1
 __getblk include/linux/buffer_head.h:382 [inline]
 sb_getblk include/linux/buffer_head.h:388 [inline]
 __ext4_get_inode_loc+0x311/0x930 fs/ext4/inode.c:4891
 ext4_get_inode_loc fs/ext4/inode.c:5019 [inline]
 ext4_reserve_inode_write+0xd7/0x250 fs/ext4/inode.c:6424
 __ext4_mark_inode_dirty+0x8c/0x3d0 fs/ext4/inode.c:6602
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6639
 __mark_inode_dirty+0x164/0x700 fs/fs-writeback.c:2709
 generic_update_time fs/inode.c:2257 [inline]
 touch_atime+0x211/0x300 fs/inode.c:2332
 file_accessed include/linux/fs.h:2272 [inline]
 ext4_file_mmap_prepare+0x13a/0x1a0 fs/ext4/file.c:840
 vfs_mmap_prepare include/linux/fs.h:2071 [inline]
 call_mmap_prepare mm/vma.c:2672 [inline]
 __mmap_region mm/vma.c:2758 [inline]
 mmap_region+0xed3/0x20c0 mm/vma.c:2860
 do_mmap+0x970/0xbc0 mm/mmap.c:560
 vm_mmap_pgoff+0x183/0x2d0 mm/util.c:581
 ksys_mmap_pgoff+0x250/0x310 mm/mmap.c:606
 x64_sys_call+0x14df/0x3020 arch/x86/include/generated/asm/syscalls_64.h:10
 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 0xffff888237d275e0 of 8 bytes by task 32 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1529
 smp_call_function_many_cond+0x297/0xb60 kernel/smp.c:856
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1077
 on_each_cpu_cond include/linux/smp.h:106 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1538
 __buffer_migrate_folio+0x309/0x4c0 mm/migrate.c:980
 buffer_migrate_folio_norefs+0x31/0x40 mm/migrate.c:1047
 move_to_new_folio+0x90/0x350 mm/migrate.c:1114
 migrate_folio_move mm/migrate.c:1383 [inline]
 migrate_folios_move mm/migrate.c:1739 [inline]
 migrate_pages_batch+0x1295/0x1f90 mm/migrate.c:1995
 migrate_pages_sync mm/migrate.c:2052 [inline]
 migrate_pages+0x1365/0x1890 mm/migrate.c:2134
 compact_zone+0x1be9/0x2730 mm/compaction.c:2668
 compact_node+0x381/0x510 mm/compaction.c:2937
 kcompactd+0x9d6/0xd80 mm/compaction.c:3235
 kthread+0x221/0x270 kernel/kthread.c:436
 ret_from_fork+0x146/0x330 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

value changed: 0x0000000000000000 -> 0xffff88810053b060

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 32 Comm: kcompactd0 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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