[PATCH 1/1] mmc: sdhci: check host->cmd is null or not in sdhci_cqe_irq()

["Ying-Chun Liu (PaulLiu)" <paul.liu@linaro.org>]

From: "Ying-Chun Liu (PaulLiu)" <paul.liu@linaro.org>

If we don't check host->cmd. We will get the following oops
when booting from eMMC on RockPi4.

 Unable to handle kernel read from unreadable memory at
   virtual address 0000000000000000
 Call trace:
   sdhci_cqe_irq+0x40/0x254

Signed-off-by: Ying-Chun Liu (PaulLiu) <paul.liu@linaro.org>
Signed-off-by: Ram Muthiah <rammuthiah@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ritesh Harjani <riteshh@codeaurora.org>
Cc: Asutosh Das <asutoshd@codeaurora.org>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: linux-mmc@vger.kernel.org
---
 drivers/mmc/host/sdhci.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 7689ffec5ad1..e0e7768bd6c0 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -3928,7 +3928,7 @@ bool sdhci_cqe_irq(struct sdhci_host *host, u32 intmask, int *cmd_error,
 
 	if (intmask & (SDHCI_INT_INDEX | SDHCI_INT_END_BIT | SDHCI_INT_CRC)) {
 		*cmd_error = -EILSEQ;
-		if (!mmc_op_tuning(host->cmd->opcode))
+		if (host->cmd && !mmc_op_tuning(host->cmd->opcode))
 			sdhci_err_stats_inc(host, CMD_CRC);
 	} else if (intmask & SDHCI_INT_TIMEOUT) {
 		*cmd_error = -ETIMEDOUT;
@@ -3938,7 +3938,7 @@ bool sdhci_cqe_irq(struct sdhci_host *host, u32 intmask, int *cmd_error,
 
 	if (intmask & (SDHCI_INT_DATA_END_BIT | SDHCI_INT_DATA_CRC)) {
 		*data_error = -EILSEQ;
-		if (!mmc_op_tuning(host->cmd->opcode))
+		if (host->cmd && !mmc_op_tuning(host->cmd->opcode))
 			sdhci_err_stats_inc(host, DAT_CRC);
 	} else if (intmask & SDHCI_INT_DATA_TIMEOUT) {
 		*data_error = -ETIMEDOUT;
-- 
2.35.1