CVE-2021-47365

Source
https://nvd.nist.gov/vuln/detail/CVE-2021-47365
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2021-47365.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2021-47365
Related
Published
2024-05-21T15:15:22Z
Modified
2024-09-11T02:00:04Z
Summary
[none]
Details

In the Linux kernel, the following vulnerability has been resolved:

afs: Fix page leak

There's a loop in afsextendwriteback() 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 findgetpages_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".

References

Affected packages

Debian:12 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.14.9-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

Debian:13 / linux

Package

Name
linux
Purl
pkg:deb/debian/linux?arch=source

Affected ranges

Type
ECOSYSTEM
Events
Introduced
0Unknown introduced version / All previous versions are affected
Fixed
5.14.9-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}