CVE-2024-57914 in Linux
Resumen
por VulDB • 2026-06-14
Enabling edge interrupts too early can cause missed ALERT events and a stuck ALERT line.
The issue arises when two Type-C ports share a single IRQ line. If the first port completes `tcpci_register_port()` and triggers an interrupt before the second port finishes `devm_request_threaded_irq()`, the interrupt handler for the second port may execute first. At this point, the `tcpci` structure for the second port is still `NULL`, leading to a NULL pointer dereference when accessing the `regmap` in `tcpci_irq()`.
To resolve this, the patch restores the previous initialization order: `devm_request_threaded_irq()` is called before `tcpci_register_port()`. However, since enabling edge interrupts in `tcpci_init()` (which occurs before `devm_request_threaded_irq()`) would cause the hardware to generate interrupts before the driver is ready to handle them, the patch explicitly sets the `ALERT_MASK` register *after* `devm_request_threaded_irq()` returns. This ensures that interrupts are only enabled once the driver is fully prepared to process them, preventing missed events and ensuring the ALERT line recovers correctly.
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