AZL-93677

In the Linux kernel, the following vulnerability has been resolved:

gpio: eic-sprd: use rawspinlockt in the irq startup path

sprdeicirqunmask() enables the GPIO IRQ and then updates controller state through sprdeicupdate(), which takes sprdeic->lock with spinlockirqsave(). The callback can be reached from irqstartup() while setting up a requested IRQ. That path is not sleepable, but on PREEMPTRT a regular spinlock_t becomes a sleeping lock.

This issue was found by our static analysis tool and then manually reviewed against the current tree.

The grounded PoC kept the requestthreadedirq() -> __setupirq() -> irqstartup() -> sprdeicirqunmask() -> sprdeicupdate() carrier and used the original spinlockirqsave(&sprdeic->lock) edge. Lockdep

BUG: sleeping function called from invalid context hardirqs last disabled at ... __setupirq.constprop.0 ... [vulnmsv] sprdrtspinlockirqsave+0x1c/0x30 [vulnmsv] sprdeicupdate.constprop.0+0x48/0x90 [vulnmsv] sprdeicirqunmask.constprop.0+0x35/0x50 [vulnmsv] __setupirq.constprop.0+0xd/0x30 [vulnmsv]

Convert the Spreadtrum EIC controller lock to rawspinlockt. The locked section only serializes MMIO register updates and does not contain sleepable operations, so keeping it non-sleeping is appropriate for the irqchip callbacks.