About this latest comment. So, CPU #0 has crashed at pc = c008000013566eb8, its ctr and r12 match, same as usual, it was called by __bpf_prog_run_save_cb as the BPF JITed program. Dumping the program from CPU #0 perspective, it has traps at that address.
It turns out the JIT fills up a whole page with traps and puts the JITed BPF program on a random offset of that page (look at kernel/bpf/core.c:bpf_jit_binary_alloc). When we go to the hotplugged CPU, however, CPU #9f (159), that same page looks different, with the code placed where it was expected. Still, it looks like fp->aux->jit_data is NULL on both CPUs, which is not as expected. I am wondering if either the icache is not being flushed properly, or RCU is not operating correctly. As other issues are not seen, more likely something related to the icache. But I don't see any IPIs involved when flushing the icache, so possibly firmware or micro- architecture related? Cascardo. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1927076 Title: IPv6 TCP in reuseport_bpf_cpu from ubuntu_kernel_selftests/net crash P8 node entei on 5.8 kernel (Oops: Exception in kernel mode, sig: 4 [#1]) Status in ubuntu-kernel-tests: New Status in The Ubuntu-power-systems project: Confirmed Status in linux package in Ubuntu: Incomplete Status in linux source package in Focal: Confirmed Status in linux source package in Hirsute: Confirmed Bug description: It looks like our P8 node "entei" tend to fail with the IPv6 TCP test from reuseport_bpf_cpu in ubuntu_kernel_selftests/net on 5.8 kernels: # send cpu 119, receive socket 119 # send cpu 121, receive socket 121 # send cpu 123, receive socket 123 # send cpu 125, receive socket 125 # send cpu 127, receive socket 127 # ---- IPv6 TCP ---- publish-job-status: using request.json It failed silently here, this can be 100% reproduced with Groovy 5.8 and Focal 5.8. This will cause the ubuntu_kernel_selftests being interrupted, the test result for other tests cannot be processed to our result page. Please find attachment for the complete "net" test result on this node with Groovy 5.8.0-52.59 Add the kqa-blocker tag as this might needs to be manually verified. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-kernel-tests/+bug/1927076/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
