{
    "data_version": "4.0",
    "data_type": "CVE",
    "data_format": "MITRE",
    "CVE_data_meta": {
        "ID": "CVE-2021-47508",
        "ASSIGNER": "cve@kernel.org",
        "STATE": "PUBLIC"
    },
    "description": {
        "description_data": [
            {
                "lang": "eng",
                "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: free exchange changeset on failures\n\nFstests runs on my VMs have show several kmemleak reports like the following.\n\n  unreferenced object 0xffff88811ae59080 (size 64):\n    comm \"xfs_io\", pid 12124, jiffies 4294987392 (age 6.368s)\n    hex dump (first 32 bytes):\n      00 c0 1c 00 00 00 00 00 ff cf 1c 00 00 00 00 00  ................\n      90 97 e5 1a 81 88 ff ff 90 97 e5 1a 81 88 ff ff  ................\n    backtrace:\n      [<00000000ac0176d2>] ulist_add_merge+0x60/0x150 [btrfs]\n      [<0000000076e9f312>] set_state_bits+0x86/0xc0 [btrfs]\n      [<0000000014fe73d6>] set_extent_bit+0x270/0x690 [btrfs]\n      [<000000004f675208>] set_record_extent_bits+0x19/0x20 [btrfs]\n      [<00000000b96137b1>] qgroup_reserve_data+0x274/0x310 [btrfs]\n      [<0000000057e9dcbb>] btrfs_check_data_free_space+0x5c/0xa0 [btrfs]\n      [<0000000019c4511d>] btrfs_delalloc_reserve_space+0x1b/0xa0 [btrfs]\n      [<000000006d37e007>] btrfs_dio_iomap_begin+0x415/0x970 [btrfs]\n      [<00000000fb8a74b8>] iomap_iter+0x161/0x1e0\n      [<0000000071dff6ff>] __iomap_dio_rw+0x1df/0x700\n      [<000000002567ba53>] iomap_dio_rw+0x5/0x20\n      [<0000000072e555f8>] btrfs_file_write_iter+0x290/0x530 [btrfs]\n      [<000000005eb3d845>] new_sync_write+0x106/0x180\n      [<000000003fb505bf>] vfs_write+0x24d/0x2f0\n      [<000000009bb57d37>] __x64_sys_pwrite64+0x69/0xa0\n      [<000000003eba3fdf>] do_syscall_64+0x43/0x90\n\nIn case brtfs_qgroup_reserve_data() or btrfs_delalloc_reserve_metadata()\nfail the allocated extent_changeset will not be freed.\n\nSo in btrfs_check_data_free_space() and btrfs_delalloc_reserve_space()\nfree the allocated extent_changeset to get rid of the allocated memory.\n\nThe issue currently only happens in the direct IO write path, but only\nafter 65b3c08606e5 (\"btrfs: fix ENOSPC failure when attempting direct IO\nwrite into NOCOW range\"), and also at defrag_one_locked_target(). Every\nother place is always calling extent_changeset_free() even if its call\nto btrfs_delalloc_reserve_space() or btrfs_check_data_free_space() has\nfailed."
            }
        ]
    },
    "problemtype": {
        "problemtype_data": [
            {
                "description": [
                    {
                        "lang": "eng",
                        "value": "n/a"
                    }
                ]
            }
        ]
    },
    "affects": {
        "vendor": {
            "vendor_data": [
                {
                    "vendor_name": "Linux",
                    "product": {
                        "product_data": [
                            {
                                "product_name": "Linux",
                                "version": {
                                    "version_data": [
                                        {
                                            "version_affected": "<",
                                            "version_name": "1da177e4c3f4",
                                            "version_value": "ca06c5cb1b6d"
                                        },
                                        {
                                            "version_value": "not down converted",
                                            "x_cve_json_5_version_data": {
                                                "versions": [
                                                    {
                                                        "version": "5.15.8",
                                                        "lessThanOrEqual": "5.15.*",
                                                        "status": "unaffected",
                                                        "versionType": "custom"
                                                    },
                                                    {
                                                        "version": "5.16",
                                                        "lessThanOrEqual": "*",
                                                        "status": "unaffected",
                                                        "versionType": "original_commit_for_fix"
                                                    }
                                                ],
                                                "defaultStatus": "affected"
                                            }
                                        }
                                    ]
                                }
                            }
                        ]
                    }
                }
            ]
        }
    },
    "references": {
        "reference_data": [
            {
                "url": "https://git.kernel.org/stable/c/ca06c5cb1b6dbfe67655b33c02fc394d65824519",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/ca06c5cb1b6dbfe67655b33c02fc394d65824519"
            },
            {
                "url": "https://git.kernel.org/stable/c/da5e817d9d75422eaaa05490d0b9a5e328fc1a51",
                "refsource": "MISC",
                "name": "https://git.kernel.org/stable/c/da5e817d9d75422eaaa05490d0b9a5e328fc1a51"
            }
        ]
    },
    "generator": {
        "engine": "bippy-a5840b7849dd"
    }
}