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 Ubuntu Bugs, which is subscribed to 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]) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-kernel-tests/+bug/1927076/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
