i3c: mipi-i3c-hci: Mask ring interrupts before ring stop request

Bus cleanup path in DMA mode may trigger a RING_OP_STAT interrupt when
the ring is being stopped. Depending on timing between ring stop request
completion, interrupt handler removal and code execution this may lead
to a NULL pointer dereference in hci_dma_irq_handler() if it gets to run
after the io_data pointer is set to NULL in hci_dma_cleanup().

Prevent this my masking the ring interrupts before ring stop request.

Signed-off-by: Jarkko Nikula <jarkko.nikula@linux.intel.com>
Link: https://lore.kernel.org/r/20240920144432.62370-2-jarkko.nikula@linux.intel.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

diff --git a/drivers/i3c/master/mipi-i3c-hci/dma.c b/drivers/i3c/master/mipi-i3c-hci/dma.c
index a918e96b21fddc584b39b06f4a60d6ab63f59f61..13adc5840094294b306466512b1a7275cc20ea4d 100644 (file)
--- a/drivers/i3c/master/mipi-i3c-hci/dma.c
+++ b/drivers/i3c/master/mipi-i3c-hci/dma.c
@@ -159,10 +159,10 @@ static void hci_dma_cleanup(struct i3c_hci *hci)
        for (i = 0; i < rings->total; i++) {
                rh = &rings->headers[i];
 
+               rh_reg_write(INTR_SIGNAL_ENABLE, 0);
                rh_reg_write(RING_CONTROL, 0);
                rh_reg_write(CR_SETUP, 0);
                rh_reg_write(IBI_SETUP, 0);
-               rh_reg_write(INTR_SIGNAL_ENABLE, 0);
 
                if (rh->xfer)
                        dma_free_coherent(&hci->master.dev,