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CVE-2026-93168

dmaengine: xilinx_dma: Fix CPU stall in xilinx_dma_poll_timeout

Products / packages Linux

Published

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Severity and exploitation

Not in CISA KEVNo CVSS score

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 21:25:33 UTC

Severity

unknown

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Not established by this record

Missing evidence does not mean no public exploit exists.

Remediation

Fix status not established

No structured fix or guidance is available here. Check the latest publisher advisory.

What this means

In the Linux kernel, the following vulnerability has been resolved:

Source excerpt · Linux

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Linux · Linux

Linux

6 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

9495f2648287029fb5545c34a0fa318426ebe84c → before 4237b5cc181a17f5a2a797655c1ce2c64e01c550

git versions

9495f2648287029fb5545c34a0fa318426ebe84c → before 2ba67aa183a3ce174d534425b67eda84f6e3c896

git versions

9495f2648287029fb5545c34a0fa318426ebe84c → before c30a26d4987a01e619449bf170f584c007e07d75

git versions

9495f2648287029fb5545c34a0fa318426ebe84c → before f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7

git versions

9495f2648287029fb5545c34a0fa318426ebe84c → before 8b5654d317277e6e505c23f8fa7e415237fefc7f

git versions

9495f2648287029fb5545c34a0fa318426ebe84c → before aa99c4d1d63bbc26a5fc4c667d89b2595743c19d

git versions

unaffected

unknown

Other versions: unaffected

Linux · Linux

Linux

8 ranges
Linux version evidence

Compare with this publisher’s ranges. This does not inspect your installation.

affected

4.6

unaffected

0 → before 4.6

semver versions

6.1.191 → through 6.1.*

semver versions

6.6.160 → through 6.6.*

semver versions

6.12.114 → through 6.12.*

semver versions

6.18.57 → through 6.18.*

semver versions

7.2.6 → through 7.2.*

semver versions

7.3 → through *

original_commit_for_fix versions

unknown

Other versions: affected

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

No structured fix or remediation guidance is available here. Check the full source description and vendor’s latest advisory for a patch or workaround; do not assume another version is safe.

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

No public exploit reference is identified in the imported evidence. This is not a claim that no exploit exists.

Original source description

Read the full publisher description

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.

References

6 sources
git.kernel.org/stable/c/4237b5cc181a17f5a2a797655c1ce2c64e01c550
Source referenceLinux
git.kernel.org/stable/c/2ba67aa183a3ce174d534425b67eda84f6e3c896
Source referenceLinux
git.kernel.org/stable/c/c30a26d4987a01e619449bf170f584c007e07d75
Source referenceLinux
git.kernel.org/stable/c/f786e7b3adbf3bd14964a1cedf9d55b6ad91dcd7
Source referenceLinux
git.kernel.org/stable/c/8b5654d317277e6e505c23f8fa7e415237fefc7f
Source referenceLinux
git.kernel.org/stable/c/aa99c4d1d63bbc26a5fc4c667d89b2595743c19d
Source referenceLinux

Inside the record

Evidence available

Package identity · not supplied
Version evidence
Remediation guidance · not supplied
Weakness classification · not supplied
Additional publishers · not supplied

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-93168

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Environment requirements

These conditions apply together as specified by the publisher. A matching product name alone does not establish exposure.

Linux · platform conditions

Any condition may hold

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 6.1.191

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 6.6.160

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 6.12.114

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 6.18.57

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 7.2.6

Vulnerable product

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*

From (inclusive): 4.6

Before: 7.3

Applicability preview
[
  {
    "nodes": [
      {
        "operator": "OR",
        "negate": false,
        "cpeMatch": [
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "6.1.191"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "6.6.160"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "6.12.114"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "6.18.57"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "7.2.6"
          },
          {
            "vulnerable": true,
            "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
            "versionStartIncluding": "4.6",
            "versionEndExcluding": "7.3"
          }
        ]
      }
    ]
  }
]
Contributing organizations · 1
Linux

Assigning organization

2026-10-30

Timeline

All times UTC

  1. Advisory published

    Publication date supplied by the source.

  2. Source updated

    Latest modification date supplied by the source.

  3. Last imported by cve.new

    Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes
No substantive changes have been recorded here yet. History starts when cve.new observes a change after tracking is enabled; earlier edits are not reconstructed.

Large field values are marked as truncated previews. Original source snapshots remain retained.