Skip to content
Heist/ feed
Unrated

dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout Currently when calling xilinx_dma_poll_timeout with delay_us=0 and a condition that is never fulfilled, the CPU busy-waits for prolonged time and the timeout triggers only with a massive delay causing a CPU stall. This happens due to a huge underestimation of wall clock time in poll_timeout_us_atomic. Commit 7349a69cf312 ("iopoll: Do not use timekeeping in read_poll_timeout_atomic()") changed the behavior to no longer use ktime_get at the expense of underestimation of wall clock time which appears to be very large for delay_us=0. Instead of timing out after approximately XILINX_DMA_LOOP_COUNT microseconds, the timeout takes XILINX_DMA_LOOP_COUNT * 1000 * (time that the overhead of the for loop in poll_timeout_us_atomic takes) which is in the range of several minutes for XILINX_DMA_LOOP_COUNT=1000000. Fix this by using a non-zero value for delay_us. Use delay_us=10 to keep the delay in the hot path of starting DMA transfers minimal but still avoid CPU stalls in case of unexpected hardware failures. One-off measurement with delay_us=0 causes the cpu to busy wait around 7 minutes in the timeout case. After applying this patch with delay_us=10 the measured timeout was 1053428 microseconds which is roughly equivalent to the expected 1000000 microseconds specified in XILINX_DMA_LOOP_COUNT. Add a constant XILINX_DMA_POLL_DELAY_US for delay_us value.

Announced Source revision 1
Original source ↗

CVE-2026-93168

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-2026-93168

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": "9495f2648287029fb5545c34a0fa318426ebe84c",
        "lessThan": "2ba67aa183a3ce174d534425b67eda84f6e3c896",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9495f2648287029fb5545c34a0fa318426ebe84c",
        "lessThan": "c30a26d4987a01e619449bf170f584c007e07d75",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9495f2648287029fb5545c34a0fa318426ebe84c",
        "lessThan": "f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9495f2648287029fb5545c34a0fa318426ebe84c",
        "lessThan": "8b5654d317277e6e505c23f8fa7e415237fefc7f",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "9495f2648287029fb5545c34a0fa318426ebe84c",
        "lessThan": "aa99c4d1d63bbc26a5fc4c667d89b2595743c19d",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/dma/xilinx/xilinx_dma.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "4.6"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "4.6",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "6.6.160",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.114",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.57",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.6",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/dma/xilinx/xilinx_dma.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-93168

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#48722 · Revision 1
Added to Heist Feed
Publisher date
Read the original announcement