This is a note to let you know that I've just added the patch titled
s390/qeth: fix underestimated count of buffer elements
to the 4.9-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:
s390-qeth-fix-underestimated-count-of-buffer-elements.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Thu Mar 8 06:55:02 PST 2018
From: Ursula Braun <ubraun@xxxxxxxxxxxxxxxxxx>
Date: Fri, 9 Feb 2018 11:03:49 +0100
Subject: s390/qeth: fix underestimated count of buffer elements
From: Ursula Braun <ubraun@xxxxxxxxxxxxxxxxxx>
[ Upstream commit 89271c65edd599207dd982007900506283c90ae3 ]
For a memory range/skb where the last byte falls onto a page boundary
(ie. 'end' is of the form xxx...xxx001), the PFN_UP() part of the
calculation currently doesn't round up to the next PFN due to an
off-by-one error.
Thus qeth believes that the skb occupies one page less than it
actually does, and may select a IO buffer that doesn't have enough spare
buffer elements to fit all of the skb's data.
HW detects this as a malformed buffer descriptor, and raises an
exception which then triggers device recovery.
Fixes: 2863c61334aa ("qeth: refactor calculation of SBALE count")
Signed-off-by: Ursula Braun <ubraun@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/s390/net/qeth_core.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -849,7 +849,7 @@ struct qeth_trap_id {
*/
static inline int qeth_get_elements_for_range(addr_t start, addr_t end)
{
- return PFN_UP(end - 1) - PFN_DOWN(start);
+ return PFN_UP(end) - PFN_DOWN(start);
}
static inline int qeth_get_micros(void)
Patches currently in stable-queue which might be from ubraun@xxxxxxxxxxxxxxxxxx are
queue-4.9/s390-qeth-fix-underestimated-count-of-buffer-elements.patch