CVE-2022-49327

Source
https://nvd.nist.gov/vuln/detail/CVE-2022-49327
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2022-49327.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2022-49327
Related
Published
2025-02-26T07:01:09Z
Modified
2025-03-13T22:49:44.996543Z
Severity
  • 5.5 (Medium) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS Calculator
Summary
[none]
Details

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

bcache: avoid journal no-space deadlock by reserving 1 journal bucket

The journal no-space deadlock was reported time to time. Such deadlock can happen in the following situation.

When all journal buckets are fully filled by active jset with heavy write I/O load, the cache set registration (after a reboot) will load all active jsets and inserting them into the btree again (which is called journal replay). If a journaled bkey is inserted into a btree node and results btree node split, new journal request might be triggered. For example, the btree grows one more level after the node split, then the root node record in cache device super block will be upgrade by bchjournalmeta() from bchbtreeset_root(). But there is no space in journal buckets, the journal replay has to wait for new journal bucket to be reclaimed after at least one journal bucket replayed. This is one example that how the journal no-space deadlock happens.

The solution to avoid the deadlock is to reserve 1 journal bucket in run time, and only permit the reserved journal bucket to be used during cache set registration procedure for things like journal replay. Then the journal space will never be fully filled, there is no chance for journal no-space deadlock to happen anymore.

This patch adds a new member "bool doreserve" in struct journal, it is inititalized to 0 (false) when struct journal is allocated, and set to 1 (true) by bchjournalspacereserve() when all initialization done in runcacheset(). In the run time when journalreclaim() tries to allocate a new journal bucket, freejournalbuckets() is called to check whether there are enough free journal buckets to use. If there is only 1 free journal bucket and journal->doreserve is 1 (true), the last bucket is reserved and freejournalbuckets() will return 0 to indicate no free journal bucket. Then journal_reclaim() will give up, and try next time to see whetheer there is free journal bucket to allocate. By this method, there is always 1 jouranl bucket reserved in run time.

During the cache set registration, journal->do_reserve is 0 (false), so the reserved journal bucket can be used to avoid the no-space deadlock.

References

Affected packages

Debian:11 / 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
5.10.127-1

Affected versions

5.*

5.10.46-4
5.10.46-5
5.10.70-1~bpo10+1
5.10.70-1
5.10.84-1
5.10.92-1~bpo10+1
5.10.92-1
5.10.92-2
5.10.103-1~bpo10+1
5.10.103-1
5.10.106-1
5.10.113-1
5.10.120-1~bpo10+1
5.10.120-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}

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
5.18.5-1

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
5.18.5-1

Ecosystem specific

{
    "urgency": "not yet assigned"
}