On Fri, 11 Jun 2021 11:56:16 +0200,
Adrian Hunter wrote:

On 11/06/21 12:03 pm, Takashi Iwai wrote:

quoted

When DMA-mapping of the bounce buffer fails, the driver tries to fall
back, but it leaves the allocated host->bounce_buffer although its
size is zero.  Later on, the driver checks the use of bounce buffer
with host->bounce_buffer pointer, and it tries to use the buffer
incorrectly, resulting in Oops.

This patch clears the release the unused buffer and clears the
bounce_buffer pointer for addressing the problem.

Signed-off-by: Takashi Iwai <redacted>

One minor comment below, otherwise:

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

quoted

---
 drivers/mmc/host/sdhci.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index bf238ade1602..5f467b98ca88 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c

@@ -4072,9 +4072,13 @@ static void sdhci_allocate_bounce_buffer(struct sdhci_host *host)
 					   bounce_size,
 					   DMA_BIDIRECTIONAL);
 	ret = dma_mapping_error(mmc_dev(mmc), host->bounce_addr);
-	if (ret)
+	if (ret) {
+		devm_kfree(mmc->parent, host->bounce_buffer);

Everywhere else in this function mmc_dev(mmc) is used, so maybe
use it here too instead of mmc->parent.

Doh, right, I wrote a patch based on the older kernel and refreshed
afterwards, but I forgot correcting this place.  Will resubmit the
fixed version.


thanks,

Takashi