LoongArch: Avoid preempt count underflow without probe
In the Linux kernel, the following vulnerability has been resolved: LoongArch: Avoid preempt count underflow without probe LoongArch uses break 11 for the breakpoint placed after an instruction that Kprobes executes out of line. Since userspace can issue the same break instruction, do_bp() can reach kprobe_singlestep_handler() when there is no current probe. The handler actually returns false in this case, but it first calls preempt_enable_no_resched(). The corresponding preempt_disable() is done by kprobe_breakpoint_handler() on a real Kprobe hit, so it has not run here. As a result, an ordinary userspace breakpoint (code 11) underflows the current task's preempt count. This also makes in_interrupt() return true until the task schedules. One visible consequence is the socket cgroup attribution: cgroup_sk_alloc() treats the allocation as interrupt context and assigns the socket to the root cgroup. A socket opened from the SIGTRAP handler can then avoid a BPF_CGROUP_INET_SOCK_CREATE policy attached to the task's own cgroup. Return as soon as kprobe_running() reports no active probe. The same check has appeared in [PATCH v10 2/4] of the original LoongArch Kprobes series, but was dropped before the feature reached mainline.
CVE-2026-89902
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-2026-89902
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": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616",
"lessThan": "ff40e597d5d98c0c45a4d09df8177202fac9520e",
"versionType": "git"
},
{
"status": "affected",
"version": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616",
"lessThan": "a1cb727fa27c2d9c7859729cd90db7bc0f46957f",
"versionType": "git"
},
{
"status": "affected",
"version": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616",
"lessThan": "76395109a051b53860faaec96522ef08ae9e8e27",
"versionType": "git"
},
{
"status": "affected",
"version": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616",
"lessThan": "c4357ebeee63cb8da1446fc936573a34e68b0f71",
"versionType": "git"
},
{
"status": "affected",
"version": "6d4cc40fb5f58147defc6c0e9d86e6232fe31616",
"lessThan": "72ce4b24676e8b3b75376c4c559dd81c1ac52d5a",
"versionType": "git"
}
],
"programFiles": [
"arch/loongarch/kernel/kprobes.c"
],
"defaultStatus": "unaffected"
},
{
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"product": "Linux",
"versions": [
{
"status": "affected",
"version": "6.3"
},
{
"status": "unaffected",
"version": "0",
"lessThan": "6.3",
"versionType": "semver"
},
{
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver",
"lessThanOrEqual": "6.6.*"
},
{
"status": "unaffected",
"version": "6.12.110",
"versionType": "semver",
"lessThanOrEqual": "6.12.*"
},
{
"status": "unaffected",
"version": "6.18.51",
"versionType": "semver",
"lessThanOrEqual": "6.18.*"
},
{
"status": "unaffected",
"version": "7.2.5",
"versionType": "semver",
"lessThanOrEqual": "7.2.*"
},
{
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix",
"lessThanOrEqual": "*"
}
],
"programFiles": [
"arch/loongarch/kernel/kprobes.c"
],
"defaultStatus": "affected"
}
]- Related CVEs
- CVE-2026-89902
Source reference:
/cveMetadata/cveId
Publisher severity
high
Source reference: /containers/cna/metrics
- Event
- #36351 · Revision 1
- Added to Heist Feed
- Publisher date