In the Linux kernel, the following vulnerability has been resolved: jbd2: fix data-race and null-ptr-deref in jbd2journaldirtymetadata() Since handle->htransaction may be a NULL pointer, so we should change it to call ishandleaborted(handle) first before dereferencing it. And the following data-race was reported in my fuzzer: ================================================================== BUG: KCSAN: data-race in jbd2journaldirtymetadata / jbd2journaldirtymetadata write to 0xffff888011024104 of 4 bytes by task 10881 on cpu 1: jbd2journaldirtymetadata+0x2a5/0x770 fs/jbd2/transaction.c:1556 _ext4handledirtymetadata+0xe7/0x4b0 fs/ext4/ext4jbd2.c:358 ext4doupdateinode fs/ext4/inode.c:5220 [inline] ext4markilocdirty+0x32c/0xd50 fs/ext4/inode.c:5869 _ext4markinodedirty+0xe1/0x450 fs/ext4/inode.c:6074 ext4dirtyinode+0x98/0xc0 fs/ext4/inode.c:6103 .... read to 0xffff888011024104 of 4 bytes by task 10880 on cpu 0: jbd2journaldirtymetadata+0xf2/0x770 fs/jbd2/transaction.c:1512 _ext4handledirtymetadata+0xe7/0x4b0 fs/ext4/ext4jbd2.c:358 ext4doupdateinode fs/ext4/inode.c:5220 [inline] ext4markilocdirty+0x32c/0xd50 fs/ext4/inode.c:5869 _ext4markinodedirty+0xe1/0x450 fs/ext4/inode.c:6074 ext4dirtyinode+0x98/0xc0 fs/ext4/inode.c:6103 .... value changed: 0x00000000 -> 0x00000001 ================================================================== This issue is caused by missing data-race annotation for jh->b_modified. Therefore, the missing annotation needs to be added.