iwlwifi: pcie: make sure prph_info is set when treating wakeup IRQ

In some rare cases when the HW is in a bad state, we may get this
interrupt when prph_info is not set yet.  Then we will try to
dereference it to check the sleep_notif element, which will cause an
oops.

Fix that by ignoring the interrupt if prph_info is not set yet.

Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20211219132536.0537aa562313.I183bb336345b9b3da196ba9e596a6f189fbcbd09@changeid
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>

diff --git a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
index 14602d6..8247014 100644 (file)
--- a/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
+++ b/drivers/net/wireless/intel/iwlwifi/pcie/rx.c
@@ -2266,7 +2266,12 @@ irqreturn_t iwl_pcie_irq_msix_handler(int irq, void *dev_id)
                }
        }
 
-       if (inta_hw & MSIX_HW_INT_CAUSES_REG_WAKEUP) {
+       /*
+        * In some rare cases when the HW is in a bad state, we may
+        * get this interrupt too early, when prph_info is still NULL.
+        * So make sure that it's not NULL to prevent crashing.
+        */
+       if (inta_hw & MSIX_HW_INT_CAUSES_REG_WAKEUP && trans_pcie->prph_info) {
                u32 sleep_notif =
                        le32_to_cpu(trans_pcie->prph_info->sleep_notif);
                if (sleep_notif == IWL_D3_SLEEP_STATUS_SUSPEND ||