{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2021-47508","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2024-05-22T06:20:56.206Z","datePublished":"2024-05-24T15:01:54.048Z","dateUpdated":"2025-12-18T11:37:45.889Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2025-12-18T11:37:45.889Z"},"descriptions":[{"lang":"en","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."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/delalloc-space.c"],"versions":[{"version":"364ecf3651e0862152c8b340d7cb3021dc0122c7","lessThan":"ca06c5cb1b6dbfe67655b33c02fc394d65824519","status":"affected","versionType":"git"},{"version":"364ecf3651e0862152c8b340d7cb3021dc0122c7","lessThan":"da5e817d9d75422eaaa05490d0b9a5e328fc1a51","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/delalloc-space.c"],"versions":[{"version":"4.13","status":"affected"},{"version":"0","lessThan":"4.13","status":"unaffected","versionType":"semver"},{"version":"5.15.8","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"5.16","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"5.15.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.13","versionEndExcluding":"5.16"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ca06c5cb1b6dbfe67655b33c02fc394d65824519"},{"url":"https://git.kernel.org/stable/c/da5e817d9d75422eaaa05490d0b9a5e328fc1a51"}],"title":"btrfs: free exchange changeset on failures","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2024-08-04T05:39:59.770Z"},"title":"CVE Program Container","references":[{"url":"https://git.kernel.org/stable/c/ca06c5cb1b6dbfe67655b33c02fc394d65824519","tags":["x_transferred"]},{"url":"https://git.kernel.org/stable/c/da5e817d9d75422eaaa05490d0b9a5e328fc1a51","tags":["x_transferred"]}]},{"metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2021-47508","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2024-09-10T15:35:39.656794Z"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2024-09-11T17:33:22.299Z"}}]}}