Bug 2562681 (CVE-2026-99188)
| Summary: | CVE-2026-99188 kernel: kernel: Denial of Service via interrupt storm during system resume in stmmac driver | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security DevOps Team <prodsec-dev> |
| Status: | NEW --- | QA Contact: | |
| Severity: | medium | Docs Contact: | |
| Priority: | medium | ||
| Version: | unspecified | CC: | akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's stmmac Ethernet driver. Network link changes prior to a system resume can leave hardware status interrupts uncleared. When the system resumes from sleep, these pending interrupts trigger an interrupt storm that overwhelms the processor, resulting in a system freeze and Denial of Service (DoS).
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
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.