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LoongArch: Avoid preempt count underflow without probe

Type: advisorySource: Official CVE List1 source record

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.

Announced Source revision 1
Original source ↗

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
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Publisher date
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