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

ALSA: usb-audio: Complete cleanup after system-resume errors

A failed system resume can leave the card unusable until reboot.
usb_audio_resume() jumps to err_out when snd_usb_pcm_resume() or
snd_usb_mixer_resume() fails. The error path skips the out: block, which
restores D0 and decrements chip->num_suspended_intf.

The card stays in SNDRV_CTL_POWER_D3hot, so later control access blocks in
snd_power_ref_and_wait(). USB core logs an interface resume callback error.
It does not retry that callback, so a later callback cannot complete the
skipped cleanup.

usb_audio_suspend() increments num_suspended_intf before returning success.
A system-resume callback must consume the system-suspend count even if a
component resume fails. Otherwise, the stranded count skews later suspend
and resume cycles.

Do not apply this cleanup to runtime-resume errors. Runtime PM can retry
-EAGAIN or -EBUSY without another suspend callback. The count must continue
to describe that suspended interface. Other runtime-resume errors latch
runtime_error in the PM core and do not cause an immediate callback retry.

Both parts of the system-resume error path are longstanding. Commit
88a8516a2128a ("ALSA: usbaudio: implement USB autosuspend") introduced
err_out past the D0 restore. Commit 862b2509d157c ("ALSA: usb-audio: Fix
inconsistent card PM state after resume") later moved
num_suspended_intf-- into the out: block. The error path now skips both
operations.

No third-party code is needed to reach the error path.
snd_usb_mixer_resume() ends in snd_usb_mixer_activate(), which returns the
result of usb_submit_urb() for devices that have a mixer status URB. Its
mixer->private_resume hook can also fail through scarlett2_init_notify().
snd_usb_pcm_resume() issues a SET_CUR request to a UAC3 power domain. It
can return -EPIPE or -EIO when the device stalls the request.

Route a component error through out: only when system_suspend is nonzero.
Continue to return runtime-resume errors through err_out. Later component
resume stages remain skipped. The original error still reaches USB core.
A later transfer can fail if the device did not recover.

I reproduced the system-resume failure on an Audient iD14 MkI with an
out-of-tree diagnostic mixer resume hook. An injected -EIO on the unpatched
core left control readers in uninterruptible sleep in
snd_power_ref_and_wait() until a reboot. With this patch, the same failure
restored control access. A second system suspend and resume also succeeded
after I disabled fault injection.
Published: 2026-09-04
Score: n/a
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

During a system resume, failures in the ALSA USB audio resume path caused the driver to skip critical cleanup steps. The device remained in a powered-down state and control access was blocked, resulting in the audio device becoming unusable until a reboot. The flaw illustrates improper resource shutdown (CWE-668).

Affected Systems

All Linux kernel releases containing the ALSA USB audio driver before the introduction of the referenced commits are affected. The issue applies to every kernel that supports USB audio devices through the ALSA subsystem and does not require any third‑party code.

Risk and Exploitability

The CVSS score is not listed, and EPSS is not available, so the exploitation probability cannot be quantified. The vulnerability is not present in the CISA KEV list. The most likely attack vector is a local privileged user or kernel attacker able to force a system suspend and resume cycle while a faulty USB audio device is attached. By repeatedly inducing the error path the device can be rendered permanently inoperable until a system reboot, effectively causing a denial‑of‑service. No known public exploits have been reported, and the fix can only be applied by patching the kernel.

Generated by OpenCVE AI on September 4, 2026 at 18:53 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Upgrade the Linux kernel to a version that contains commits 88a8516a2128 and 862b2509d157, which restore proper cleanup after system resume errors.
  • Confirm the device performs a successful resume immediately after the kernel update by testing with a typical suspend/resume cycle.
  • As a temporary workaround, disable USB autosuspend or system suspend callbacks for the audio device by adding a udev rule that sets ‘usbcore.autosuspend=-1’ or by manually preventing resume callbacks for that device.

Generated by OpenCVE AI on September 4, 2026 at 18:53 UTC.

Tracking

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Advisories

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History

Fri, 04 Sep 2026 16:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: ALSA: usb-audio: Complete cleanup after system-resume errors A failed system resume can leave the card unusable until reboot. usb_audio_resume() jumps to err_out when snd_usb_pcm_resume() or snd_usb_mixer_resume() fails. The error path skips the out: block, which restores D0 and decrements chip->num_suspended_intf. The card stays in SNDRV_CTL_POWER_D3hot, so later control access blocks in snd_power_ref_and_wait(). USB core logs an interface resume callback error. It does not retry that callback, so a later callback cannot complete the skipped cleanup. usb_audio_suspend() increments num_suspended_intf before returning success. A system-resume callback must consume the system-suspend count even if a component resume fails. Otherwise, the stranded count skews later suspend and resume cycles. Do not apply this cleanup to runtime-resume errors. Runtime PM can retry -EAGAIN or -EBUSY without another suspend callback. The count must continue to describe that suspended interface. Other runtime-resume errors latch runtime_error in the PM core and do not cause an immediate callback retry. Both parts of the system-resume error path are longstanding. Commit 88a8516a2128a ("ALSA: usbaudio: implement USB autosuspend") introduced err_out past the D0 restore. Commit 862b2509d157c ("ALSA: usb-audio: Fix inconsistent card PM state after resume") later moved num_suspended_intf-- into the out: block. The error path now skips both operations. No third-party code is needed to reach the error path. snd_usb_mixer_resume() ends in snd_usb_mixer_activate(), which returns the result of usb_submit_urb() for devices that have a mixer status URB. Its mixer->private_resume hook can also fail through scarlett2_init_notify(). snd_usb_pcm_resume() issues a SET_CUR request to a UAC3 power domain. It can return -EPIPE or -EIO when the device stalls the request. Route a component error through out: only when system_suspend is nonzero. Continue to return runtime-resume errors through err_out. Later component resume stages remain skipped. The original error still reaches USB core. A later transfer can fail if the device did not recover. I reproduced the system-resume failure on an Audient iD14 MkI with an out-of-tree diagnostic mixer resume hook. An injected -EIO on the unpatched core left control readers in uninterruptible sleep in snd_power_ref_and_wait() until a reboot. With this patch, the same failure restored control access. A second system suspend and resume also succeeded after I disabled fault injection.
Title ALSA: usb-audio: Complete cleanup after system-resume errors
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-04T15:54:32.894Z

Reserved: 2026-08-26T14:34:25.795Z

Link: CVE-2026-80828

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-04T16:18:10.833

Modified: 2026-09-04T16:18:10.833

Link: CVE-2026-80828

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T19:00:14Z

Weaknesses

No weakness.