loop0: detected capacity change from 0 to 2048
==================================================================
BUG: KCSAN: data-race in __find_get_block / has_bh_in_lru

read-write to 0xffff888237c2bb10 of 8 bytes by task 5933 on cpu 0:
 bh_lru_install fs/buffer.c:1343 [inline]
 __find_get_block+0x434/0x8a0 fs/buffer.c:1406
 __getblk_slow fs/buffer.c:1131 [inline]
 bdev_getblk+0x139/0x3b0 fs/buffer.c:1437
 __bread_gfp+0x52/0x280 fs/buffer.c:1491
 sb_bread include/linux/buffer_head.h:346 [inline]
 fat__get_entry fs/fat/dir.c:100 [inline]
 fat_get_entry+0x482/0x5f0 fs/fat/dir.c:128
 fat_get_short_entry fs/fat/dir.c:885 [inline]
 fat_subdirs+0xfa/0x190 fs/fat/dir.c:951
 fat_read_root+0x2d3/0x310 fs/fat/inode.c:1345
 fat_fill_super+0x14f5/0x1bf0 fs/fat/inode.c:1814
 vfat_fill_super+0x24/0x30 fs/fat/namei_vfat.c:1200
 get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 vfat_get_tree+0x1c/0x30 fs/fat/namei_vfat.c:1205
 vfs_get_tree+0x56/0x1e0 fs/super.c:1814
 do_new_mount+0x227/0x690 fs/namespace.c:3507
 path_mount+0x49b/0xb30 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4034
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4034
 x64_sys_call+0x203e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237c2bb10 of 8 bytes by task 5935 on cpu 1:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1527
 smp_call_function_many_cond+0x2d5/0xc20 kernel/smp.c:837
 on_each_cpu_cond_mask+0x3c/0x90 kernel/smp.c:1051
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1536
 kill_bdev block/bdev.c:90 [inline]
 set_blocksize+0x24c/0x270 block/bdev.c:173
 sb_set_blocksize block/bdev.c:182 [inline]
 sb_min_blocksize+0x63/0xe0 block/bdev.c:198
 ext4_load_super fs/ext4/super.c:4992 [inline]
 __ext4_fill_super fs/ext4/super.c:5213 [inline]
 ext4_fill_super+0x38b/0x3a10 fs/ext4/super.c:5686
 get_tree_bdev_flags+0x29f/0x310 fs/super.c:1636
 get_tree_bdev+0x1f/0x30 fs/super.c:1659
 ext4_get_tree+0x1c/0x30 fs/ext4/super.c:5718
 vfs_get_tree+0x56/0x1e0 fs/super.c:1814
 do_new_mount+0x227/0x690 fs/namespace.c:3507
 path_mount+0x49b/0xb30 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount+0x27c/0x2d0 fs/namespace.c:4034
 __x64_sys_mount+0x67/0x80 fs/namespace.c:4034
 x64_sys_call+0x203e/0x2d60 arch/x86/include/generated/asm/syscalls_64.h:166
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff888106f9ad00 -> 0xffff888106f9ae38

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 UID: 0 PID: 5935 Comm: syz.0.903 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
==================================================================
EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
EXT4-fs error (device loop0): ext4_validate_block_bitmap:441: comm syz.0.903: bg 0: block 274: padding at end of block bitmap is not set
EXT4-fs (loop0): Delayed block allocation failed for inode 16 at logical offset 16 with max blocks 16 with error 117
EXT4-fs (loop0): This should not happen!! Data will be lost