Re: v4.14-rc2/arm64 kernel BUG at net/core/skbuff.c:2626
From: Mark Rutland
Date: Mon Oct 02 2017 - 13:36:04 EST
On Mon, Oct 02, 2017 at 10:27:15AM -0700, Eric Dumazet wrote:
> On Mon, Oct 2, 2017 at 10:21 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
> > On Mon, Oct 02, 2017 at 07:48:28AM -0700, Eric Dumazet wrote:
> >> Please try the following fool proof patch.
> >> This is what I had in my local tree back in August but could not
> >> conclude on the syzkaller bug I was working on.
> >> diff --git a/net/ipv4/icmp.c b/net/ipv4/icmp.c
> >> index 681e33998e03b609fdca83a83e0fc62a3fee8c39..e51d777797a927058760a1ab7af00579f7488cb5 100644
> >> --- a/net/ipv4/icmp.c
> >> +++ b/net/ipv4/icmp.c
> >> @@ -732,7 +732,8 @@ void icmp_send(struct sk_buff *skb_in, int type, int code, __be32 info)
> >> room = 576;
> >> room -= sizeof(struct iphdr) + icmp_param.replyopts.opt.opt.optlen;
> >> room -= sizeof(struct icmphdr);
> >> -
> >> + if (room < 0)
> >> + goto ende;
> >> icmp_param.data_len = skb_in->len - icmp_param.offset;
> >> if (icmp_param.data_len > room)
> >> icmp_param.data_len = room;
> > Unfortuantely, with this applied I still see the issue.
> > Syzkaller came up with a minimized reproducer , which can trigger the
> > issue near instantly under syz-execprog. If there's anything that would
> > help to narrow this down, I'm more than happy to give it a go.
> > Thanks,
> > Mark.
> >  https://www.kernel.org/pub/linux/kernel/people/mark/bugs/20171002-skb_clone-misaligned-atomic/syzkaller.repro
> Note that I was not trying to address the misaligned stuff.
Aargh, I put the reproducer in the wrong folder thanks to tab-completing
my kup command. :/
The reproducer linked above is for the kernel BUG at
I've uploaded a copy into the relevant bug directory , but that'll
take a little while to sync out. I'll drop it from the misalignment bug
folder once that's visible to all.
Sorry about that!