Linux Kernel: stmmac DWMAC1000 RGMII ISR Clear Soft Lockup
CVE-2026-99188 Published on October 28, 2026
net: stmmac: dwmac1000: clear the RGMII status interrupt
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.
Products Associated with CVE-2026-99188
Want to know whenever a new CVE is published for Linux Kernel? stack.watch will email you.
Affected Versions
Linux:- Version 2e2c878a314175a4c3b76ee3be455f543438f472 and below affc6d572935282ef9ab1e0b790cbc31e5ad8bca is affected.
- Version 2e2c878a314175a4c3b76ee3be455f543438f472 and below aa07285705f8d5bac464eb1c5b7412f8e88b91e1 is affected.
- Version 6.19 is affected.
- Before 6.19 is unaffected.
- Version 7.2.13, <= 7.2.* is unaffected.
- Version 7.3, <= * is unaffected.