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BUG: KCSAN: data-race in ext4_mb_find_by_goal / mb_mark_used

read to 0xffff88812a6e3494 of 4 bytes by task 5888 on cpu 0:
 ext4_mb_find_by_goal+0x156/0x770 fs/ext4/mballoc.c:1829
 ext4_mb_regular_allocator+0xfd/0x9d0 fs/ext4/mballoc.c:2118
 ext4_mb_new_blocks+0xf6f/0x1de0 fs/ext4/mballoc.c:4539
 ext4_ext_map_blocks+0x1c1e/0x2330 fs/ext4/extents.c:4460
 ext4_map_blocks+0x23a/0xfa0 fs/ext4/inode.c:640
 ext4_alloc_file_blocks+0x1bd/0x6c0 fs/ext4/extents.c:4649
 ext4_fallocate+0x507/0x13d0 fs/ext4/extents.c:4934
 vfs_fallocate+0x3be/0x650 fs/open.c:309
 ioctl_preallocate+0x126/0x180 fs/ioctl.c:490
 file_ioctl fs/ioctl.c:506 [inline]
 do_vfs_ioctl+0xbd2/0xc60 fs/ioctl.c:696
 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x4c/0x60 fs/ioctl.c:718
 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffff88812a6e3494 of 4 bytes by task 5890 on cpu 1:
 mb_mark_used+0x190/0x940 fs/ext4/mballoc.c:1574
 ext4_mb_use_best_found+0x111/0x310 fs/ext4/mballoc.c:1645
 ext4_mb_find_by_goal+0x615/0x770 fs/ext4/mballoc.c:1872
 ext4_mb_regular_allocator+0xfd/0x9d0 fs/ext4/mballoc.c:2118
 ext4_mb_new_blocks+0xf6f/0x1de0 fs/ext4/mballoc.c:4539
 ext4_ext_map_blocks+0x1c1e/0x2330 fs/ext4/extents.c:4460
 ext4_map_blocks+0x23a/0xfa0 fs/ext4/inode.c:640
 ext4_alloc_file_blocks+0x1bd/0x6c0 fs/ext4/extents.c:4649
 ext4_fallocate+0x507/0x13d0 fs/ext4/extents.c:4934
 vfs_fallocate+0x3be/0x650 fs/open.c:309
 ioctl_preallocate+0x126/0x180 fs/ioctl.c:490
 file_ioctl fs/ioctl.c:506 [inline]
 do_vfs_ioctl+0xbd2/0xc60 fs/ioctl.c:696
 ksys_ioctl+0xbd/0xe0 fs/ioctl.c:713

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 5890 Comm: syz-executor.5 Not tainted 5.4.0-rc3+ #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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