Bug 2562681 (CVE-2026-99188) - CVE-2026-99188 kernel: kernel: Denial of Service via interrupt storm during system resume in stmmac driver
Summary: CVE-2026-99188 kernel: kernel: Denial of Service via interrupt storm during s...
Keywords:
Status: NEW
Alias: CVE-2026-99188
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
medium
medium
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-10-28 10:48 UTC by OSIDB Bzimport
Modified: 2026-10-29 07:48 UTC (History)
17 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
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Description OSIDB Bzimport 2026-10-28 10:48:51 UTC
In the Linux kernel, the following vulnerability has been resolved:

net: stmmac: dwmac1000: clear the RGMII status interrupt

Since commit 2e2c878a3141 ("net: stmmac: remove SGMII/RGMII/SMII
interrupt handling") nothing on the RGMII path reads GMAC_RGSMIIIS, so
RGSMIIIS stays pending behind GMAC_INT_MASK from the first link change
on. stmmac_resume() resets the MAC in stmmac_hw_setup(); the reset sets
GMAC_INT_MASK to 0 until dwmac1000_core_init() writes the mask again,
and the pending status storms the line:

  dwmac_dma_interrupt: unexpected status 04000000

A register dump at the first message on ODROID-HC4 showed it:

  core int_status 00000001 int_mask 00000000 pmt 00000000 rgsmiiis 0000000d

When the resume thread runs on the CPU that takes the MAC interrupt,
the storm starves it: a soft lockup, then a watchdog reset or a hang.

Read GMAC_RGSMIIIS in dwmac1000_irq_status() when the status is not
masked, as the driver did before 2e2c878a3141; the read clears it.

Wake-on-LAN resume from s2idle with the resume thread and the MAC
interrupt on one CPU: Helios64 (dwmac-rk), 7.3-rc6, soft-locked in 3 of
3 resumes without a fix and in 0 of 10 with this patch; it ran with an
out-of-tree dwmac-rk change that keeps the GMAC powered across suspend.
ODROID-HC4 (dwmac-meson8b): 0 of 10 with this patch, 2 of 2 without a
fix on a 7.3-rc5 build. irq_rgmii_n went up by one per resume.


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