loop0: detected capacity change from 264192 to 0
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BUG: KCSAN: data-race in ext4_mb_good_group / mb_mark_used

read-write to 0xffff888101f50888 of 4 bytes by task 8462 on cpu 1:
 mb_mark_used+0x2b8/0xc10 fs/ext4/mballoc.c:1619
 ext4_mb_use_best_found+0x102/0x2f0 fs/ext4/mballoc.c:1678
 ext4_mb_measure_extent fs/ext4/mballoc.c:1793 [inline]
 ext4_mb_complex_scan_group+0x33f/0x830 fs/ext4/mballoc.c:2024
 ext4_mb_regular_allocator+0x1044/0x1890 fs/ext4/mballoc.c:2417
 ext4_mb_new_blocks+0x6e8/0x1140 fs/ext4/mballoc.c:4975
 ext4_ext_map_blocks+0x15a0/0x1fc0 fs/ext4/extents.c:4238
 ext4_map_blocks+0x700/0xfc0 fs/ext4/inode.c:637
 ext4_getblk+0xb1/0x3c0 fs/ext4/inode.c:847
 ext4_bread+0x28/0x130 fs/ext4/inode.c:899
 ext4_append+0xd1/0x1b0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2758
 ext4_mkdir+0x319/0x730 fs/ext4/namei.c:2803
 vfs_mkdir+0x288/0x350 fs/namei.c:3652
 do_mkdirat+0x132/0x220 fs/namei.c:3675
 __do_sys_mkdir fs/namei.c:3691 [inline]
 __se_sys_mkdir fs/namei.c:3689 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3689
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888101f50888 of 4 bytes by task 12594 on cpu 0:
 ext4_mb_good_group+0x140/0x350 fs/ext4/mballoc.c:2095
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2190 [inline]
 ext4_mb_regular_allocator+0xc3b/0x1890 fs/ext4/mballoc.c:2386
 ext4_mb_new_blocks+0x6e8/0x1140 fs/ext4/mballoc.c:4975
 ext4_ext_map_blocks+0x15a0/0x1fc0 fs/ext4/extents.c:4238
 ext4_map_blocks+0x700/0xfc0 fs/ext4/inode.c:637
 ext4_getblk+0xb1/0x3c0 fs/ext4/inode.c:847
 ext4_bread+0x28/0x130 fs/ext4/inode.c:899
 ext4_append+0xd1/0x1b0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2758
 ext4_mkdir+0x319/0x730 fs/ext4/namei.c:2803
 vfs_mkdir+0x288/0x350 fs/namei.c:3652
 do_mkdirat+0x132/0x220 fs/namei.c:3675
 __do_sys_mkdir fs/namei.c:3691 [inline]
 __se_sys_mkdir fs/namei.c:3689 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3689
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 12594 Comm: syz-executor.0 Not tainted 5.11.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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