CVE-2026-98767usb: dwc3: gadget: fix IRQ storm on invalid event buffer count

Official description

In the Linux kernel, the following vulnerability has been resolved: usb: dwc3: gadget: fix IRQ storm on invalid event buffer count When dwc3_check_event_buf() reads a GEVNTCOUNT value exceeding the event buffer length, commit 63ccd26cd1f6 ("usb: dwc3: gadget: check that event count does not exceed event buffer length") returns IRQ_NONE without writing back GEVNTCOUNT. Since the DWC3 interrupt is level-triggered, the uncleared IRQ source keeps the line asserted, causing a tight IRQ storm that accumulates 99,900 unhandled interrupts and triggers spurious.c:184 BUG -> kernel panic. The resulting call stack: __report_bad_irq+0xac/0xc8 note_interrupt+0x340/0x468 handle_irq_event+0xac/0xc0 handle_fasteoi_irq+0x120/0x228 gic_handle_irq+0x68/0x108 ... kernel BUG at kernel/irq/spurious.c:184 To reproduce, write a bogus value exceeding the event buffer length directly to the GEVNTCOUNT register: devmem <DWC3_BASE + 0xc40c> 4 0x1004 Write the bogus count back to GEVNTCOUNT to clear the IRQ source, consistent with the stale event clearing pattern in dwc3_event_buffers_setup(), and schedule error recovery to reinitialize the controller.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/2c41e442ff6304532bf369aa618b23c8a474feb4
• https://git.kernel.org/stable/c/86b9c867fb061a147df05ff0d9bb69dd3d79f49a
• https://git.kernel.org/stable/c/6cd82563bb270e03fe2f91324660ea14e3ce5d1a
• https://git.kernel.org/stable/c/96918ca25ff467c25675478fc79393df4ae9d74c
• https://git.kernel.org/stable/c/ba927133b301894e7d24099afbb701887c8cd2f1
• https://git.kernel.org/stable/c/f51cadb02b439850ab411df0a2cf4288a66d42e2
• https://git.kernel.org/stable/c/1ff77cbefe5a653ea12874c213ea4bd0d72c1067