==================================================================
BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d27ce0 of 8 bytes by task 3532 on cpu 1:
 bh_lru_install fs/buffer.c:1234 [inline]
 find_get_block_common+0x457/0x870 fs/buffer.c:1299
 bdev_getblk+0x4b/0x370 fs/buffer.c:-1
 __bread_gfp+0x51/0x230 fs/buffer.c:1404
 sb_bread include/linux/buffer_head.h:377 [inline]
 fat_ent_bread+0xbe/0x1a0 fs/fat/fatent.c:109
 fat_ent_read+0x3b6/0x5c0 fs/fat/fatent.c:372
 fat_get_cluster+0x4f8/0x830 fs/fat/cache.c:261
 fat_bmap_cluster fs/fat/cache.c:294 [inline]
 fat_get_mapped_cluster+0xea/0x250 fs/fat/cache.c:315
 fat_bmap+0x250/0x280 fs/fat/cache.c:379
 __fat_get_block fs/fat/inode.c:130 [inline]
 fat_get_block+0xd3/0x5e0 fs/fat/inode.c:191
 block_read_full_folio+0x1eb/0x680 fs/buffer.c:2309
 do_mpage_readpage+0x29f/0xe80 fs/mpage.c:313
 mpage_read_folio+0xbd/0x130 fs/mpage.c:394
 fat_read_folio+0x1c/0x30 fs/fat/inode.c:206
 filemap_read_folio+0x2e/0x110 mm/filemap.c:2549
 filemap_fault+0x5a0/0xbd0 mm/filemap.c:3706
 __do_fault mm/memory.c:5677 [inline]
 do_read_fault mm/memory.c:6112 [inline]
 do_fault mm/memory.c:6246 [inline]
 do_pte_missing mm/memory.c:4778 [inline]
 handle_pte_fault mm/memory.c:6665 [inline]
 __handle_mm_fault mm/memory.c:6817 [inline]
 handle_mm_fault+0x19eb/0x3bd0 mm/memory.c:6984
 faultin_page mm/gup.c:1130 [inline]
 __get_user_pages+0xeaf/0x1930 mm/gup.c:1432
 populate_vma_page_range mm/gup.c:1868 [inline]
 __mm_populate+0x2a0/0x3c0 mm/gup.c:1971
 mm_populate include/linux/mm.h:4451 [inline]
 vm_mmap_pgoff+0x260/0x310 mm/util.c:586
 ksys_mmap_pgoff+0x250/0x310 mm/mmap.c:619
 x64_sys_call+0x23b3/0x2550 arch/x86/include/generated/asm/syscalls_64.h:10
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d27ce0 of 8 bytes by task 3543 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1440
 smp_call_function_many_cond+0x2d1/0xbc0 kernel/smp.c:962
 on_each_cpu_cond_mask+0x35/0x50 kernel/smp.c:1195
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1449
 __buffer_migrate_folio+0x304/0x4c0 mm/migrate.c:991
 buffer_migrate_folio_norefs+0x31/0x40 mm/migrate.c:1058
 move_to_new_folio+0x90/0x350 mm/migrate.c:1125
 migrate_folio_move mm/migrate.c:1391 [inline]
 migrate_folios_move mm/migrate.c:1748 [inline]
 migrate_pages_batch+0x1175/0x1c90 mm/migrate.c:2004
 migrate_pages_sync mm/migrate.c:2061 [inline]
 migrate_pages+0x135b/0x1880 mm/migrate.c:2143
 compact_zone+0x1df4/0x2980 mm/compaction.c:2698
 compact_node mm/compaction.c:2945 [inline]
 compact_nodes mm/compaction.c:2967 [inline]
 sysctl_compaction_handler+0x39d/0x550 mm/compaction.c:3018
 proc_sys_call_handler+0x2ec/0x4a0 fs/proc/proc_sysctl.c:600
 proc_sys_write+0x22/0x30 fs/proc/proc_sysctl.c:626
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0x57a/0x990 fs/read_write.c:687
 ksys_write+0xdc/0x1a0 fs/read_write.c:739
 __do_sys_write fs/read_write.c:750 [inline]
 __se_sys_write fs/read_write.c:747 [inline]
 __x64_sys_write+0x40/0x50 fs/read_write.c:747
 x64_sys_call+0x154e/0x2550 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
 do_syscall_64+0x112/0x360 arch/x86/entry/syscall_64.c:84
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x0000000000000000 -> 0xffff888106f88ae0

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3543 Comm: syz.3.14 Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
==================================================================
syz.3.14 (3543) used greatest stack depth: 10552 bytes left