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Patch "[media] saa7164: fix double fetch PCIe access condition" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message Aug 8, 2017

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Stable branch Media (V4L/DVB)
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This is a note to let you know that I've just added the patch titled

[media] saa7164: fix double fetch PCIe access condition

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
saa7164-fix-double-fetch-pcie-access-condition.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 6fb05e0dd32e566facb96ea61a48c7488daa5ac3 Mon Sep 17 00:00:00 2001

From: Steven Toth <[email protected]>
Date: Tue, 6 Jun 2017 09:30:27 -0300
Subject: [media] saa7164: fix double fetch PCIe access condition

From: Steven Toth <[email protected]>

commit 6fb05e0dd32e566facb96ea61a48c7488daa5ac3 upstream.

Avoid a double fetch by reusing the values from the prior transfer.

Originally reported via https://bugzilla.kernel.org/show_bug.cgi?id=195559

Thanks to Pengfei Wang <[email protected]> for reporting.

Signed-off-by Steven Toth <[email protected]>
Reported-by Pengfei Wang <[email protected]>
Signed-off-by Mauro Carvalho Chehab <[email protected]>
Cc Eduardo Valentin <[email protected]>
Signed-off-by Greg Kroah-Hartman <[email protected]>
---
 drivers/media/pci/saa7164/saa7164-bus.c |   13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)
drivers/media/pci/saa7164/saa7164-bus.c +1 -12
@@ -393,11 +393,11 @@ int saa7164_bus_get(struct saa7164_dev *
 	msg_tmp.size = le16_to_cpu((__force __le16)msg_tmp.size);
 	msg_tmp.command = le32_to_cpu((__force __le32)msg_tmp.command);
 	msg_tmp.controlselector = le16_to_cpu((__force __le16)msg_tmp.controlselector);
+	memcpy(msg, &msg_tmp, sizeof(*msg));
 
 	/* No need to update the read positions, because this was a peek */
 	/* If the caller specifically want to peek, return */
 	if (peekonly) {
-		memcpy(msg, &msg_tmp, sizeof(*msg));
 		goto peekout;
 	}
 

@@ -442,21 +442,15 @@ int saa7164_bus_get(struct saa7164_dev *
 		space_rem = bus->m_dwSizeGetRing - curr_grp;
 
 		if (space_rem < sizeof(*msg)) {
-			/* msg wraps around the ring */
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, space_rem);
-			memcpy_fromio((u8 *)msg + space_rem, bus->m_pdwGetRing,
-				sizeof(*msg) - space_rem);
 			if (buf)
 				memcpy_fromio(buf, bus->m_pdwGetRing + sizeof(*msg) -
 					space_rem, buf_size);
 
 		} else if (space_rem == sizeof(*msg)) {
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 			if (buf)
 				memcpy_fromio(buf, bus->m_pdwGetRing, buf_size);
 		} else {
 			/* Additional data wraps around the ring */
-			memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 			if (buf) {
 				memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp +
 					sizeof(*msg), space_rem - sizeof(*msg));

@@ -469,15 +463,10 @@ int saa7164_bus_get(struct saa7164_dev *
 
 	} else {
 		/* No wrapping */
-		memcpy_fromio(msg, bus->m_pdwGetRing + curr_grp, sizeof(*msg));
 		if (buf)
 			memcpy_fromio(buf, bus->m_pdwGetRing + curr_grp + sizeof(*msg),
 				buf_size);
 	}
-	/* Convert from little endian to CPU */
-	msg->size = le16_to_cpu((__force __le16)msg->size);
-	msg->command = le32_to_cpu((__force __le32)msg->command);
-	msg->controlselector = le16_to_cpu((__force __le16)msg->controlselector);
 
 	/* Update the read positions, adjusting the ring */
 	saa7164_writel(bus->m_dwGetReadPos, new_grp);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/saa7164-fix-double-fetch-pcie-access-condition.patch