loop5: detected capacity change from 0 to 87
==================================================================
BUG: KCSAN: data-race in ext4_mb_good_group / mb_mark_used

read-write to 0xffff8881005b1014 of 4 bytes by task 5456 on cpu 1:
 mb_mark_used+0x128/0xb50 fs/ext4/mballoc.c:2065
 ext4_mb_use_best_found+0xf6/0x2a0 fs/ext4/mballoc.c:2147
 ext4_mb_check_limits fs/ext4/mballoc.c:2211 [inline]
 ext4_mb_complex_scan_group+0x7a7/0x810 fs/ext4/mballoc.c:2527
 ext4_mb_regular_allocator+0x11b4/0x23a0 fs/ext4/mballoc.c:2943
 ext4_mb_new_blocks+0x801/0x2020 fs/ext4/mballoc.c:6217
 ext4_ext_map_blocks+0x1008/0x35c0 fs/ext4/extents.c:4379
 ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
 ext4_map_blocks+0x5aa/0xd20 fs/ext4/inode.c:702
 ext4_getblk+0x11f/0x530 fs/ext4/inode.c:849
 ext4_bread+0x2c/0x110 fs/ext4/inode.c:912
 ext4_append+0x164/0x2a0 fs/ext4/namei.c:83
 ext4_init_new_dir+0x13a/0x470 fs/ext4/namei.c:2988
 ext4_mkdir+0x313/0x740 fs/ext4/namei.c:3034
 vfs_mkdir+0x1f4/0x320 fs/namei.c:4313
 do_mkdirat+0x136/0x2c0 fs/namei.c:4336
 __do_sys_mkdirat fs/namei.c:4351 [inline]
 __se_sys_mkdirat fs/namei.c:4349 [inline]
 __x64_sys_mkdirat+0x4e/0x60 fs/namei.c:4349
 x64_sys_call+0x1b6f/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:259
 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 0xffff8881005b1014 of 4 bytes by task 5461 on cpu 0:
 ext4_mb_good_group+0xc2/0x330 fs/ext4/mballoc.c:2591
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2713 [inline]
 ext4_mb_regular_allocator+0xd9c/0x23a0 fs/ext4/mballoc.c:2903
 ext4_mb_new_blocks+0x801/0x2020 fs/ext4/mballoc.c:6217
 ext4_ext_map_blocks+0x1008/0x35c0 fs/ext4/extents.c:4379
 ext4_map_create_blocks fs/ext4/inode.c:516 [inline]
 ext4_map_blocks+0x5aa/0xd20 fs/ext4/inode.c:702
 ext4_getblk+0x11f/0x530 fs/ext4/inode.c:849
 ext4_bread+0x2c/0x110 fs/ext4/inode.c:912
 ext4_append+0x164/0x2a0 fs/ext4/namei.c:83
 ext4_init_new_dir+0x13a/0x470 fs/ext4/namei.c:2988
 ext4_mkdir+0x313/0x740 fs/ext4/namei.c:3034
 vfs_mkdir+0x1f4/0x320 fs/namei.c:4313
 do_mkdirat+0x136/0x2c0 fs/namei.c:4336
 __do_sys_mkdirat fs/namei.c:4351 [inline]
 __se_sys_mkdirat fs/namei.c:4349 [inline]
 __x64_sys_mkdirat+0x4e/0x60 fs/namei.c:4349
 x64_sys_call+0x1b6f/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:259
 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: 0x000006b8 -> 0x000006b7

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 5461 Comm: syz-executor.5 Not tainted 6.14.0-rc2-syzkaller-00162-g68763b29e0a6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 12/27/2024
==================================================================
/dev/loop5: Can't open blockdev
syz-executor.5 (5461) used greatest stack depth: 10616 bytes left