nuttx/arch/arm
Jukka Laitinen d8deca6c52 arch/arm/imx9, arch/arm64/imx9: Release eDMA lock before callbacks
Fix a potential deadlock in the DMA driver. DMA completion callbacks
may immediately submit another transfer, for example:

imx9_dmaterminate()
  -> imx9_dma_txcallback()
    -> imx9_dma_txavailable()
      -> uart_xmitchars_dma()
        -> imx9_dma_send()
          -> imx9_dmach_stop()
	    -> imx9_dmaterminate()

Resulting dmaterminate to take the same spinlock again. Fix this by moving
the spin_unlock_irqrestore_nopreempt before calling the callback. It is not
necessary to keep dma channel locked during the callback; the channel is
already free at this point.

This doesn't directly affect arch/arm/imx9 (the cortex-m version) because
it is not SMP (the spinlock is reduced to blocking irqs), but it is worth
fixing at the same to keep drivers in sync.

Signed-off-by: Jukka Laitinen <jukka.laitinen@tii.ae>
2026-09-15 08:41:58 -03:00
..
include libs/libc/machine/arm: Relocate FDPIC function descriptors. 2026-09-13 16:03:32 -03:00
src arch/arm/imx9, arch/arm64/imx9: Release eDMA lock before callbacks 2026-09-15 08:41:58 -03:00
CMakeLists.txt
Kconfig binfmt, arch/arm: Add the CONFIG_FDPIC option and the ABI header. 2026-09-08 16:31:16 -03:00