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BUG: KCSAN: data-race in ext4_mb_regular_allocator / mb_mark_used

write to 0xffff88821aad9014 of 4 bytes by task 24284 on cpu 1:
 mb_mark_used+0x135/0xba0 fs/ext4/mballoc.c:1637
 ext4_mb_use_best_found+0x102/0x2f0 fs/ext4/mballoc.c:1708
 ext4_mb_measure_extent fs/ext4/mballoc.c:1827 [inline]
 ext4_mb_complex_scan_group+0x345/0x820 fs/ext4/mballoc.c:2058
 ext4_mb_regular_allocator+0xcda/0xfe0 fs/ext4/mballoc.c:2328
 ext4_mb_new_blocks+0x304/0xcf0 fs/ext4/mballoc.c:4721
 ext4_new_meta_blocks+0x84/0x180 fs/ext4/balloc.c:667
 ext4_ext_grow_indepth fs/ext4/extents.c:1282 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1386 [inline]
 ext4_ext_insert_extent+0x9b3/0x2b80 fs/ext4/extents.c:2059
 ext4_split_extent_at+0x6cb/0xb10 fs/ext4/extents.c:3213
 ext4_force_split_extent_at fs/ext4/extents.c:305 [inline]
 ext4_swap_extents+0xd35/0x1330 fs/ext4/extents.c:5655
 move_extent_per_page+0x131a/0x1560 fs/ext4/move_extent.c:339
 ext4_move_extents+0xa98/0xbe0 fs/ext4/move_extent.c:673
 ext4_ioctl+0x2051/0x3920 fs/ext4/ioctl.c:986
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xc9/0x130 fs/ioctl.c:760
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:760
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88821aad9014 of 4 bytes by task 24278 on cpu 0:
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2186 [inline]
 ext4_mb_regular_allocator+0x6f9/0xfe0 fs/ext4/mballoc.c:2297
 ext4_mb_new_blocks+0x304/0xcf0 fs/ext4/mballoc.c:4721
 ext4_new_meta_blocks+0x84/0x180 fs/ext4/balloc.c:667
 ext4_ext_grow_indepth fs/ext4/extents.c:1282 [inline]
 ext4_ext_create_new_leaf fs/ext4/extents.c:1386 [inline]
 ext4_ext_insert_extent+0x9b3/0x2b80 fs/ext4/extents.c:2059
 ext4_split_extent_at+0x6cb/0xb10 fs/ext4/extents.c:3213
 ext4_force_split_extent_at fs/ext4/extents.c:305 [inline]
 ext4_swap_extents+0xd35/0x1330 fs/ext4/extents.c:5655
 move_extent_per_page+0x131a/0x1560 fs/ext4/move_extent.c:339
 ext4_move_extents+0xa98/0xbe0 fs/ext4/move_extent.c:673
 ext4_ioctl+0x2051/0x3920 fs/ext4/ioctl.c:986
 vfs_ioctl fs/ioctl.c:48 [inline]
 ksys_ioctl fs/ioctl.c:753 [inline]
 __do_sys_ioctl fs/ioctl.c:762 [inline]
 __se_sys_ioctl+0xc9/0x130 fs/ioctl.c:760
 __x64_sys_ioctl+0x3f/0x50 fs/ioctl.c:760
 do_syscall_64+0x51/0xb0 arch/x86/entry/common.c:384
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 24278 Comm: syz-executor.4 Not tainted 5.8.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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