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xprtrdma: Decouple req recycling from RPC completion

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: xprtrdma: Decouple req recycling from RPC completion rl_kref formerly served two distinct lifetimes through a single refcount: it gated when a Reply could wake its RPC task, and it gated when an rpcrdma_req could return to its free pool. The marshal path took the Send-side reference only when SGEs needed DMA-unmap (sc_unmap_count > 0), which made a Send carrying only pre-registered buffers an exception: the Reply handler dropped rl_kref from 1 to 0 and freed the req while the HCA might still be DMA-reading from its send buffer. Give rl_kref a narrower job. The RPC layer takes one reference when slot allocation hands a req out. rpcrdma_prepare_send_sges() takes a Send-side reference unconditionally after WR preparation succeeds. xprt_rdma_free_slot() and xprt_rdma_bc_free_rqst() drop the RPC-layer reference; rpcrdma_sendctx_unmap() drops the Send-side reference. The req returns to its free pool only after both owners have signed off. The existing kref_init(&req->rl_kref) call in rpcrdma_prepare_send_sges() is removed. Initialization moves to the slot-allocation paths (xprt_rdma_alloc_slot and rpcrdma_bc_rqst_get), and the release callback re-arms rl_kref before the req returns to a free pool. A re-init in the marshal path would discard the RPC-layer reference that already exists on entry. Three invariants follow: - Any rpcrdma_req held by an rpc_rqst has rl_kref >= 1. xprt_rdma_alloc_slot(), rpcrdma_bc_rqst_ge

Announced Source revision 1
Original source ↗

CVE-2026-72473

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-2026-72473

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": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "740975054a1970c0cf15f70ac39724a064f45847",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "9f3d9b68c1c6c51746e5ecdb52b2e6a2901de37e",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "e7632089523acddcdd8f090ad19e96fb3107b04d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "53442c7d0c888e51b8bc3da196970a669cc6b294",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "8203f760a72bd39a3b66bc4eff0aa272a99fe22b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "0ab115237025f5e379620bbcd56a02697d07b002",
        "lessThan": "e786233d2e0bbff9a82e43f02ae3a46ab4b08ec3",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "net/sunrpc/xprtrdma/backchannel.c",
      "net/sunrpc/xprtrdma/rpc_rdma.c",
      "net/sunrpc/xprtrdma/transport.c",
      "net/sunrpc/xprtrdma/verbs.c",
      "net/sunrpc/xprtrdma/xprt_rdma.h"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.3"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.3",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.1.178",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.145",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.97",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.40",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.5",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "net/sunrpc/xprtrdma/backchannel.c",
      "net/sunrpc/xprtrdma/rpc_rdma.c",
      "net/sunrpc/xprtrdma/transport.c",
      "net/sunrpc/xprtrdma/verbs.c",
      "net/sunrpc/xprtrdma/xprt_rdma.h"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-72473

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33064 · Revision 1
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Publisher date
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