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BUG: KCSAN: data-race in ext4_mb_good_group / mb_free_blocks

read-write to 0xffff888100539018 of 4 bytes by task 2965 on cpu 1:
 mb_free_blocks+0x498/0xbc0 fs/ext4/mballoc.c:-1
 ext4_free_data_in_buddy fs/ext4/mballoc.c:3964 [inline]
 ext4_process_freed_data+0x301/0x690 fs/ext4/mballoc.c:4000
 ext4_journal_commit_callback+0x65/0x3a0 fs/ext4/super.c:514
 jbd2_journal_commit_transaction+0x2901/0x3150 fs/jbd2/commit.c:1121
 kjournald2+0x211/0x3d0 fs/jbd2/journal.c:201
 kthread+0x489/0x510 kernel/kthread.c:463
 ret_from_fork+0x122/0x1b0 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245

read to 0xffff888100539018 of 4 bytes by task 3924 on cpu 0:
 ext4_mb_good_group+0xdf/0x310 fs/ext4/mballoc.c:2688
 ext4_mb_good_group_nolock fs/ext4/mballoc.c:2806 [inline]
 ext4_mb_scan_group+0x7ea/0xf10 fs/ext4/mballoc.c:2934
 ext4_mb_scan_groups_linear fs/ext4/mballoc.c:1146 [inline]
 ext4_mb_scan_groups fs/ext4/mballoc.c:1180 [inline]
 ext4_mb_regular_allocator+0x70a/0x15e0 fs/ext4/mballoc.c:3026
 ext4_mb_new_blocks+0x800/0x2080 fs/ext4/mballoc.c:6295
 ext4_ext_map_blocks+0xff5/0x38a0 fs/ext4/extents.c:4383
 ext4_map_create_blocks fs/ext4/inode.c:609 [inline]
 ext4_map_blocks+0x5ee/0xd00 fs/ext4/inode.c:811
 ext4_getblk+0x114/0x510 fs/ext4/inode.c:978
 ext4_bread+0x28/0x110 fs/ext4/inode.c:1041
 ext4_append+0x16e/0x2b0 fs/ext4/namei.c:83
 ext4_init_new_dir+0xec/0x180 fs/ext4/namei.c:2981
 ext4_mkdir+0x31f/0x740 fs/ext4/namei.c:3017
 vfs_mkdir+0x213/0x340 fs/namei.c:4453
 do_mkdirat+0x132/0x3f0 fs/namei.c:4486
 __do_sys_mkdirat fs/namei.c:4503 [inline]
 __se_sys_mkdirat fs/namei.c:4501 [inline]
 __x64_sys_mkdirat+0x4c/0x60 fs/namei.c:4501
 x64_sys_call+0x2b7/0x3000 arch/x86/include/generated/asm/syscalls_64.h:259
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd2/0x200 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000003 -> 0x00000005

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 3924 Comm: syz-executor.3 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
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