On Tue, Nov 22, 2016 at 9:06 AM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Nov 22, 2016 at 05:59:12PM +0100, Andre Noll wrote: >> On Mon, Nov 21, 10:28, Greg KH wrote >> > I'm announcing the release of the 4.4.34 kernel. >> > >> > All users of the 4.4 kernel series must upgrade. >> >> This update broke PXE boot on our 4-way AMD boxes. The kernel panics in >> eth_type_trans(), presumably during kernel-level IP autoconfiguration, >> see [1]. Bisection points me at 5c67f947 (net: __skb_flow_dissect() >> must cap its return value). And indeed, reverting this commit fixes >> the problem for me. >> >> Investigation showed that the real problem is not the change in the >> above commit per se (i.e., capping ->thoff) but the fact that in the >> success case, where we jump to the "out_good" label, ->thoff is now >> set *after* ->n_proto and ->ip_proto. I fail to see how order matters >> here, but it clearly does, since the crash is 100% reproducible, >> and is fixed by the commit below (on top of v4.4.34). >> >> Please consider applying something like the patch below for mainline >> and -stable. > > If this issue is also the same for Linus's tree, we should cc: netdev so > that the patch can get into there, right? > > thanks, > > greg k-h We definitely want to fix the real bug, not working around it. Seems an aliasing problem, key_control and key_basic might point to adjacent memory and a barrier() would solve the issue as well. Adding a test in fast path looks overkill to me. Thanks. -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html