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BUG: KCSAN: data-race in __filemap_add_folio / filemap_write_and_wait_range

read-write to 0xffff88810048af78 of 8 bytes by task 3728 on cpu 1:
 __filemap_add_folio+0x66e/0x880 mm/filemap.c:919
 filemap_add_folio+0x1d3/0x350 mm/filemap.c:966
 __filemap_get_folio_mpol+0x32e/0x840 mm/filemap.c:2022
 __filemap_get_folio include/linux/pagemap.h:761 [inline]
 grow_dev_folio fs/buffer.c:960 [inline]
 grow_buffers fs/buffer.c:1026 [inline]
 __getblk_slow fs/buffer.c:1044 [inline]
 bdev_getblk+0x170/0x3c0 fs/buffer.c:1439
 sb_getblk_gfp include/linux/buffer_head.h:394 [inline]
 __ext4_sb_bread_gfp fs/ext4/super.c:237 [inline]
 ext4_sb_bread_unmovable+0x65/0x190 fs/ext4/super.c:266
 ext4_load_super fs/ext4/super.c:5154 [inline]
 __ext4_fill_super fs/ext4/super.c:5358 [inline]
 ext4_fill_super+0x44b/0x3760 fs/ext4/super.c:5828
 get_tree_bdev_flags+0x291/0x300 fs/super.c:1634
 get_tree_bdev+0x1f/0x30 fs/super.c:1657
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5860
 vfs_get_tree+0x57/0x1d0 fs/super.c:1694
 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

read to 0xffff88810048af78 of 8 bytes by task 2979 on cpu 0:
 mapping_needs_writeback mm/filemap.c:634 [inline]
 filemap_write_and_wait_range+0x59/0x370 mm/filemap.c:683
 filemap_write_and_wait include/linux/pagemap.h:65 [inline]
 sync_blockdev block/bdev.c:276 [inline]
 bdev_release+0xd4/0x3d0 block/bdev.c:1129
 blkdev_release+0x15/0x20 block/fops.c:680
 __fput+0x29e/0x630 fs/file_table.c:512
 fput_close_sync+0xad/0x190 fs/file_table.c:617
 __do_sys_close fs/open.c:1511 [inline]
 __se_sys_close fs/open.c:1496 [inline]
 __x64_sys_close+0x55/0xf0 fs/open.c:1496
 x64_sys_call+0x275d/0x3020 arch/x86/include/generated/asm/syscalls_64.h:4
 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: 0x0000000000000000 -> 0x0000000000000001

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 2979 Comm: udevd Not tainted syzkaller #0 PREEMPT(lazy) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/25/2026
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