syzbot

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BUG: KCSAN: data-race in ext4_mb_good_group / mb_free_blocks

write to 0xffff888100439b58 of 4 bytes by task 344 on cpu 1:
 mb_free_blocks+0x323/0xb40
 ext4_free_data_in_buddy fs/ext4/mballoc.c:3662 [inline]
 ext4_process_freed_data+0x4c9/0x9a0 fs/ext4/mballoc.c:3713
 ext4_journal_commit_callback+0x82/0x1f0 fs/ext4/super.c:448
 jbd2_journal_commit_transaction+0x2b7a/0x3430 fs/jbd2/commit.c:1171
 kjournald2+0x268/0x490 fs/jbd2/journal.c:213
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff888100439b58 of 4 bytes by task 498 on cpu 0:
 ext4_mb_good_group+0x151/0x370 fs/ext4/mballoc.c:2436
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2545 [inline]
 ext4_mb_regular_allocator+0x1610/0x2530 fs/ext4/mballoc.c:2747
 ext4_mb_new_blocks+0x792/0x1fc0 fs/ext4/mballoc.c:5586
 ext4_ext_map_blocks+0x15ed/0x1ff0 fs/ext4/extents.c:4250
 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+0x2c3/0x3e0 fs/namei.c:3885
 do_mkdirat+0x12e/0x2c0 fs/namei.c:3911
 __do_sys_mkdir fs/namei.c:3931 [inline]
 __se_sys_mkdir fs/namei.c:3929 [inline]
 __x64_sys_mkdir+0x40/0x50 fs/namei.c:3929
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000004 -> 0x00000016

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 498 Comm: syz-executor.1 Tainted: G        W         5.15.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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