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

write to 0xffff8881005d7b54 of 4 bytes by task 1807 on cpu 0:
 mb_mark_used+0x13b/0xc50 fs/ext4/mballoc.c:1943
 ext4_mb_use_best_found+0x102/0x320 fs/ext4/mballoc.c:2015
 ext4_mb_measure_extent fs/ext4/mballoc.c:2131 [inline]
 ext4_mb_complex_scan_group+0x349/0x850 fs/ext4/mballoc.c:2361
 ext4_mb_regular_allocator+0x1a22/0x2520 fs/ext4/mballoc.c:2760
 ext4_mb_new_blocks+0x762/0x1f90 fs/ext4/mballoc.c:5515
 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4245
 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638
 ext4_getblk+0xb1/0x3d0 fs/ext4/inode.c:848
 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:2885
 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2931
 vfs_mkdir+0x2a4/0x370 fs/namei.c:3823
 do_mkdirat+0x11d/0x200 fs/namei.c:3848
 __do_sys_mkdir fs/namei.c:3866 [inline]
 __se_sys_mkdir fs/namei.c:3864 [inline]
 __x64_sys_mkdir+0x32/0x40 fs/namei.c:3864
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

read to 0xffff8881005d7b54 of 4 bytes by task 9092 on cpu 1:
 ext4_mb_avg_fragment_size_cmp fs/ext4/mballoc.c:835 [inline]
 ext4_mb_rb_insert fs/ext4/mballoc.c:811 [inline]
 mb_update_avg_fragment_size+0x184/0x260 fs/ext4/mballoc.c:859
 mb_mark_used+0xae0/0xc50 fs/ext4/mballoc.c:1994
 ext4_mb_use_best_found+0x102/0x320 fs/ext4/mballoc.c:2015
 ext4_mb_simple_scan_group+0x253/0x3a0 fs/ext4/mballoc.c:2293
 ext4_mb_regular_allocator+0x1974/0x2520 fs/ext4/mballoc.c:2755
 ext4_mb_new_blocks+0x762/0x1f90 fs/ext4/mballoc.c:5515
 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4245
 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638
 ext4_iomap_alloc fs/ext4/inode.c:3426 [inline]
 ext4_iomap_begin+0x4a0/0x620 fs/ext4/inode.c:3476
 iomap_apply+0x8d/0x400 fs/iomap/apply.c:46
 __iomap_dio_rw+0x62e/0xa60 fs/iomap/direct-io.c:561
 iomap_dio_rw+0x30/0x70 fs/iomap/direct-io.c:649
 ext4_dio_write_iter fs/ext4/file.c:568 [inline]
 ext4_file_write_iter+0xa4f/0x11d0 fs/ext4/file.c:678
 call_write_iter include/linux/fs.h:2114 [inline]
 do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740
 do_iter_write+0x112/0x4c0 fs/read_write.c:866
 vfs_iter_write+0x4c/0x70 fs/read_write.c:907
 iter_file_splice_write+0x40a/0x750 fs/splice.c:689
 do_splice_from fs/splice.c:767 [inline]
 direct_splice_actor+0x80/0xa0 fs/splice.c:936
 splice_direct_to_actor+0x345/0x650 fs/splice.c:891
 do_splice_direct+0xf5/0x170 fs/splice.c:979
 do_sendfile+0x773/0xda0 fs/read_write.c:1260
 __do_sys_sendfile64 fs/read_write.c:1325 [inline]
 __se_sys_sendfile64 fs/read_write.c:1311 [inline]
 __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1311
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0000590e -> 0x0000590d

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 9092 Comm: syz-executor.3 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
==================================================================
syz-executor.3 (9092) used greatest stack depth: 9568 bytes left