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 4.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: s390-qeth-fix-underestimated-count-of-buffer-elements.patch and it can be found in the queue-4.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Tue Mar 6 19:02:57 PST 2018
From: Ursula Braun ubraun@linux.vnet.ibm.com Date: Fri, 9 Feb 2018 11:03:49 +0100 Subject: s390/qeth: fix underestimated count of buffer elements
From: Ursula Braun ubraun@linux.vnet.ibm.com
[ 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@linux.vnet.ibm.com Signed-off-by: Julian Wiedmann jwi@linux.vnet.ibm.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -836,7 +836,7 @@ 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@linux.vnet.ibm.com are
queue-4.15/s390-qeth-fix-underestimated-count-of-buffer-elements.patch