ghsa-95jq-x6q9-c9cq
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
afs: Fix page leak
There's a loop in afs_extend_writeback() that adds extra pages to a write we want to make to improve the efficiency of the writeback by making it larger. This loop stops, however, if we hit a page we can't write back from immediately, but it doesn't get rid of the page ref we speculatively acquired.
This was caused by the removal of the cleanup loop when the code switched from using find_get_pages_contig() to xarray scanning as the latter only gets a single page at a time, not a batch.
Fix this by putting the page on a ref on an early break from the loop. Unfortunately, we can't just add that page to the pagevec we're employing as we'll go through that and add those pages to the RPC call.
This was found by the generic/074 test. It leaks ~4GiB of RAM each time it is run - which can be observed with "top".
{
"affected": [],
"aliases": [
"CVE-2021-47365"
],
"database_specific": {
"cwe_ids": [
"CWE-459"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-21T15:15:22Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix page leak\n\nThere\u0027s a loop in afs_extend_writeback() that adds extra pages to a write\nwe want to make to improve the efficiency of the writeback by making it\nlarger. This loop stops, however, if we hit a page we can\u0027t write back\nfrom immediately, but it doesn\u0027t get rid of the page ref we speculatively\nacquired.\n\nThis was caused by the removal of the cleanup loop when the code switched\nfrom using find_get_pages_contig() to xarray scanning as the latter only\ngets a single page at a time, not a batch.\n\nFix this by putting the page on a ref on an early break from the loop.\nUnfortunately, we can\u0027t just add that page to the pagevec we\u0027re employing\nas we\u0027ll go through that and add those pages to the RPC call.\n\nThis was found by the generic/074 test. It leaks ~4GiB of RAM each time it\nis run - which can be observed with \"top\".",
"id": "GHSA-95jq-x6q9-c9cq",
"modified": "2025-05-12T21:30:55Z",
"published": "2024-05-21T15:31:44Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47365"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/581b2027af0018944ba301d68e7af45c6d1128b5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/d130b5fdd42254d92948d06347940276140c927e"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
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- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.