syzbot

==================================================================
BUG: KCSAN: data-race in ext4_mb_regular_allocator / mb_mark_used

write to 0xffff888101372b54 of 4 bytes by task 3722 on cpu 1:
 mb_mark_used+0x13b/0xc50 fs/ext4/mballoc.c:1947
 ext4_mb_use_best_found+0x102/0x300 fs/ext4/mballoc.c:2019
 ext4_mb_measure_extent fs/ext4/mballoc.c:2135 [inline]
 ext4_mb_complex_scan_group+0x359/0x880 fs/ext4/mballoc.c:2365
 ext4_mb_regular_allocator+0x19c8/0x24a0 fs/ext4/mballoc.c:2778
 ext4_mb_new_blocks+0x78c/0x1ee0 fs/ext4/mballoc.c:5586
 ext4_ext_map_blocks+0x1658/0x2120 fs/ext4/extents.c:4285
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 ext4_getblk+0xc6/0x3e0 fs/ext4/inode.c:847
 ext4_bread+0x28/0x100 fs/ext4/inode.c:900
 ext4_append+0xd1/0x1c0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2893
 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2939
 vfs_mkdir+0x2c8/0x3d0 fs/namei.c:3883
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3909
 __do_sys_mkdir fs/namei.c:3929 [inline]
 __se_sys_mkdir fs/namei.c:3927 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3927
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff888101372b54 of 4 bytes by task 3874 on cpu 0:
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2504 [inline]
 ext4_mb_regular_allocator+0xa97/0x24a0 fs/ext4/mballoc.c:2747
 ext4_mb_new_blocks+0x78c/0x1ee0 fs/ext4/mballoc.c:5586
 ext4_ext_map_blocks+0x1658/0x2120 fs/ext4/extents.c:4285
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 ext4_getblk+0xc6/0x3e0 fs/ext4/inode.c:847
 ext4_bread+0x28/0x100 fs/ext4/inode.c:900
 ext4_append+0xd1/0x1c0 fs/ext4/namei.c:67
 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2893
 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2939
 vfs_mkdir+0x2c8/0x3d0 fs/namei.c:3883
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3909
 __do_sys_mkdir fs/namei.c:3929 [inline]
 __se_sys_mkdir fs/namei.c:3927 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3927
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xd0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000064a -> 0x00000649

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 3874 Comm: syz-executor.0 Not tainted 5.16.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================