Hi Stefan, On 05/07/18 13:16, Stefan Schmidt wrote: > Hello. > > [CC David Palma and Rabi Narayan Sahoo] > > On 02.07.2018 22:32, Alexander Aring wrote: >> This patch fixes patch add handling to take care tail and headroom for >> single 6lowpan frames. We need to be sure we have a skb with the right >> head and tailroom for single frames. This patch do it by using >> skb_copy_expand() if head and tailroom is not enough allocated by upper >> layer. >> >> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=195059 >> Reported-by: David Palma <[email protected]> >> Reported-by: Rabi Narayan Sahoo <[email protected]> >> Signed-off-by: Alexander Aring <[email protected]> > > David, Rabi and you please test these two patches and verify that it > fixes the problems you have? > > regards > Stefan Schmidt >
The patches fix the problems!
I've tested them against different packet sizes and no kernel panic.
The patches were applied in Debian's 4.9.88-1+deb9u1 x86_64 kernel,
which before the patches showed the reported issue.
Thanks again to Alex for looking into it.
Cheers,
--
David
>> ---
>> net/ieee802154/6lowpan/tx.c | 21 ++++++++++++++++++---
>> 1 file changed, 18 insertions(+), 3 deletions(-)
>>
>> diff --git a/net/ieee802154/6lowpan/tx.c b/net/ieee802154/6lowpan/tx.c
>> index e6ff5128e61a..d0c4d220de08 100644
>> --- a/net/ieee802154/6lowpan/tx.c
>> +++ b/net/ieee802154/6lowpan/tx.c
>> @@ -265,9 +265,24 @@ netdev_tx_t lowpan_xmit(struct sk_buff *skb, struct
>> net_device *ldev)
>> /* We must take a copy of the skb before we modify/replace the ipv6
>> * header as the header could be used elsewhere
>> */
>> - skb = skb_unshare(skb, GFP_ATOMIC);
>> - if (!skb)
>> - return NET_XMIT_DROP;
>> + if (unlikely(skb_headroom(skb) < ldev->needed_headroom ||
>> + skb_tailroom(skb) < ldev->needed_tailroom)) {
>> + struct sk_buff *nskb;
>> +
>> + nskb = skb_copy_expand(skb, ldev->needed_headroom,
>> + ldev->needed_tailroom, GFP_ATOMIC);
>> + if (likely(skb)) {
>> + consume_skb(skb);
>> + skb = nskb;
>> + } else {
>> + kfree_skb(skb);
>> + return NET_XMIT_DROP;
>> + }
>> + } else {
>> + skb = skb_unshare(skb, GFP_ATOMIC);
>> + if (!skb)
>> + return NET_XMIT_DROP;
>> + }
>>
>> ret = lowpan_header(skb, ldev, &dgram_size, &dgram_offset);
>> if (ret < 0) {
>>
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