Re: Bug in ks8851.c

2 messages, 2 authors, 2013-03-29 · open the first message on its own page

Re: Bug in ks8851.c

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: 2013-03-28 19:31:57

Max,
 please cc the actual maintainers of the driver. The patch looks sane,
though. I assume you've tested it in practice?

You also seem to have based this on an ancient version, the code has
long since moved from drivers/net/ks8851.c to
drivers/net/ethernet/micrel/ks8851.c (back in June of 2011), and it's
missing a sign-off from you.

I'm attaching an updated patch for the rename/capitalization issue.

     Linus

On Thu, Mar 28, 2013 at 11:25 AM,  [off-list ref] wrote:
quoted hunk
According to the Datasheet (page 52):
15-12 Reserved
11-0 RXBC Receive Byte Count
This field indicates the present received frame byte size.

I suppose the code has a bug:
                rxh = ks8851_rdreg32(ks, KS_RXFHSR);
                rxstat = rxh & 0xffff;
                rxlen = rxh >> 16; // BUG!!! 0xFFF mask should be applied

P.S.
without bit mask applied I saw rxlen equal to 15360 which is bigger then
entire RX queue size (12KB).

Thanks,
Max Nekludov

From cb3199cee4490f98d6062e32a75ca377a32b55bc Mon Sep 17 00:00:00 2001
From: Max Neklyudov <redacted>
Date: Tue, 26 Mar 2013 11:46:57 +0400
Subject: [PATCH] Fix bug in ks8851 driver

---
 drivers/net/ks8851.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ks8851.c b/drivers/net/ks8851.c
index 91a93cb..0dc03da 100644
--- a/drivers/net/ks8851.c
+++ b/drivers/net/ks8851.c
@@ -553,7 +553,7 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
        for (; rxfc != 0; rxfc--) {
                rxh = ks8851_rdreg32(ks, KS_RXFHSR);
                rxstat = rxh & 0xffff;
-               rxlen = rxh >> 16;
+               rxlen = (rxh >> 16) & 0xFFF;

                netif_dbg(ks, rx_status, ks->netdev,
                          "rx: stat 0x%04x, len 0x%04x\n", rxstat, rxlen);
--
1.7.10.4

Re: Bug in ks8851.c

From: <hidden>
Date: 2013-03-29 05:18:14

Linus,

I tried to send the mail to 'Ben Dooks [off-list ref]' but the address
is dead now.
I assume you've tested it in practice?
Yes, I'm running the modified code both in bootloader and Linux kernel on
my board.

Thanks,
Max

 Signed-off-by: Max Nekludov [off-list ref]
 ---
 drivers/net/ethernet/micrel/ks8851.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/micrel/ks8851.c
b/drivers/net/ethernet/micrel/ks8851.c
index 33bcb63d56a2..8fb481252e2c 100644
--- a/drivers/net/ethernet/micrel/ks8851.c
+++ b/drivers/net/ethernet/micrel/ks8851.c
@@ -528,7 +528,7 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
 	for (; rxfc != 0; rxfc--) {
 		rxh = ks8851_rdreg32(ks, KS_RXFHSR);
 		rxstat = rxh & 0xffff;
-		rxlen = rxh >> 16;
+		rxlen = (rxh >> 16) & 0xfff;

 		netif_dbg(ks, rx_status, ks->netdev,
 			  "rx: stat 0x%04x, len 0x%04x\n", rxstat, rxlen);



Max,
 please cc the actual maintainers of the driver. The patch looks sane,
though. I assume you've tested it in practice?

You also seem to have based this on an ancient version, the code has
long since moved from drivers/net/ks8851.c to
drivers/net/ethernet/micrel/ks8851.c (back in June of 2011), and it's
missing a sign-off from you.

I'm attaching an updated patch for the rename/capitalization issue.

     Linus

On Thu, Mar 28, 2013 at 11:25 AM,  [off-list ref] wrote:
quoted hunk
According to the Datasheet (page 52):
15-12 Reserved
11-0 RXBC Receive Byte Count
This field indicates the present received frame byte size.

I suppose the code has a bug:
                rxh = ks8851_rdreg32(ks, KS_RXFHSR);
                rxstat = rxh & 0xffff;
                rxlen = rxh >> 16; // BUG!!! 0xFFF mask should be applied

P.S.
without bit mask applied I saw rxlen equal to 15360 which is bigger then
entire RX queue size (12KB).

Thanks,
Max Nekludov

From cb3199cee4490f98d6062e32a75ca377a32b55bc Mon Sep 17 00:00:00 2001
From: Max Neklyudov <redacted>
Date: Tue, 26 Mar 2013 11:46:57 +0400
Subject: [PATCH] Fix bug in ks8851 driver

---
 drivers/net/ks8851.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ks8851.c b/drivers/net/ks8851.c
index 91a93cb..0dc03da 100644
--- a/drivers/net/ks8851.c
+++ b/drivers/net/ks8851.c
@@ -553,7 +553,7 @@ static void ks8851_rx_pkts(struct ks8851_net *ks)
        for (; rxfc != 0; rxfc--) {
                rxh = ks8851_rdreg32(ks, KS_RXFHSR);
                rxstat = rxh & 0xffff;
-               rxlen = rxh >> 16;
+               rxlen = (rxh >> 16) & 0xFFF;

                netif_dbg(ks, rx_status, ks->netdev,
                          "rx: stat 0x%04x, len 0x%04x\n", rxstat,
rxlen);
--
1.7.10.4

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attached file: patch.diff)
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