btrfs: harden block_group::bg_list against list_del() races
In the Linux kernel, the following vulnerability has been resolved: btrfs: harden block_group::bg_list against list_del() races As far as I can tell, these calls of list_del_init() on bg_list cannot run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(), as they are in transaction error paths and situations where the block group is readonly. However, if there is any chance at all of racing with mark_bg_unused(), or a different future user of bg_list, better to be safe than sorry. Otherwise we risk the following interleaving (bg_list refcount in parens) T1 (some random op) T2 (btrfs_mark_bg_unused) !list_empty(&bg->bg_list); (1) list_del_init(&bg->bg_list); (1) list_move_tail (1) btrfs_put_block_group (0) btrfs_delete_unused_bgs bg = list_first_entry list_del_init(&bg->bg_list); btrfs_put_block_group(bg); (-1) Ultimately, this results in a broken ref count that hits zero one deref early and the real final deref underflows the refcount, resulting in a WARNING.
CVE-2025-37856
Primary source · Revision 1
Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.
Security context
Source reference: cve:CVE-2025-37856
Linux
Source reference: /containers/cna/affected/0/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Linux
Source reference: /containers/cna/affected/1/product
- Affected versions
- Not stated in this record
- Fixed versions
- Not stated in this record
- Prerequisites
- Not stated in this record
Structured affected-version data
Original package identities and version rules from this source.
[
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
"lessThan": "9039afe6240ae01d6caf2fa731590ac74fb8a69b",
"versionType": "git"
},
{
"status": "affected",
"version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
"lessThan": "bf089c4d1141b27332c092b1dcca5022c415a3b6",
"versionType": "git"
},
{
"status": "affected",
"version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
"lessThan": "909e60fb469d4101c6b08cf6e622efb062bb24a1",
"versionType": "git"
},
{
"status": "affected",
"version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
"lessThan": "185fd73e5ac06027c4be9a129e59193f6a3ef202",
"versionType": "git"
},
{
"status": "affected",
"version": "a9f189716cf15913c453299d72f69c51a9b0f86b",
"lessThan": "7511e29cf1355b2c47d0effb39e463119913e2f6",
"versionType": "git"
},
{
"status": "affected",
"version": "edf3b5aadb2515c808200b904baa5b70a727f0ac",
"versionType": "git"
},
{
"status": "affected",
"version": "01eca70ef8cf499d0cb6d1bbd691558e7792cf17",
"versionType": "git"
},
{
"status": "affected",
"version": "5d19abcffd8404078dfa7d7118cec357b5e7bc58",
"versionType": "git"
},
{
"status": "affected",
"version": "5.15.128",
"lessThan": "5.16",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.1.47",
"lessThan": "6.2",
"versionType": "semver"
},
{
"status": "affected",
"version": "6.4.12",
"lessThan": "6.5",
"versionType": "semver"
}
],
"programFiles": [
"fs/btrfs/extent-tree.c",
"fs/btrfs/transaction.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.5"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.5",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.160",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.24",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.13.12",
"versionType": "semver",
"lessThanOrEqual": "6.13.*"
},
{
"status": "unaffected",
"version": "6.14.3",
"versionType": "semver",
"lessThanOrEqual": "6.14.*"
},
{
"status": "unaffected",
"version": "6.15",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"fs/btrfs/extent-tree.c",
"fs/btrfs/transaction.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2025-37856
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #45973 · Revision 1
- Added to Heist Feed
- Publisher date