Hi Bhupesh and Dave (and everybody CC'ed here), I'm Guilherme Piccoli and I'm working in the same issue observed in RH bugzilla 1758323 [0] - or at least, it seems to be the the same heh
The reported issue in my case was that the 2nd kexec fails on Nitro instanced, and indeed it's reproducible. More than this, it shows as an initrd corruption. I've found 2 workarounds, using the "new" kexec syscall (by doing kexec -s -l) and keep the initrd memory "un-freed", using the kernel parameter "retain_initrd". I've noticed that your interesting investigation in the BZ led to SWIOTLB as a potential culprit, but trying with "swiotlb=noforce" or even "iommu=off" didn't help me. Also, worth notice a weird behavior: seems Amazon Linux 2 (based on kernel 4.14) sometimes works, or better saying, in some instances it works. I have 2x t3.large instances, in one of them I can make the Amazon Linux works (and to isolate potential out-of-tree patches, I've used Amazon Linux 2 config file and built a mainline 4.14, which also works in that particular instance). The reason for this email is to ask if you managed to figure the issue root-cause, or have some leads. I continue the debug here, but it's a bit difficult without access to AWS hypervisor (and it seems like a hypervisor issue for me). The fact that preserving the initrd memory prevents the problem seems to indicate that after freeing such high-address memory, the hypervisor somewhat manages to use that regardless if some other code is using that...ending up corrupting the initrd. I've also looped the kexec list in order to grow the audience, maybe somebody already faced that kind of issues and have some ideas. A collaboration in this debug would be greatly appreciate by me, it's a quite interesting issue and I'm looking forward to understand what's going on. Thanks in advance, Guilherme [0]https://bugzilla.redhat.com/show_bug.cgi?id=1758323 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
