On Wed, 29 Mar 2023 15:07:49 +0200 Denys Vlasenko <vda.li...@googlemail.com> wrote:
> On Wed, Mar 1, 2023 at 12:01*PM alice <al...@ayaya.dev> wrote: > > On Tue Feb 28, 2023 at 11:17 PM CET, wrote: > > > I'm having an intermittent issue with "BusyBox v1.36.0 (2023-01-03 > > > 22:49:12 > > > UTC)" (the one from the Docker image busybox:musl) when running on amd64 > > > GitHub > > > actions runner VMs (azure). > > > > > > When I use sha256sum it is getting terminated with SIGILL, Illegal > > > instruction. The issue is hard to reproduce but I have a GitHub actions > > > CI/CD > > > job that I can re-run repeatedly (no changes to code, environment, data > > > input, > > > etc) that will occasionally have the issue. I managed to capture a core > > > dump. > > > > this was also reported in > > http://lists.busybox.net/pipermail/busybox/2023-January/090113.html > > > > it's caused by having a cpu with AVX512 (the github runners do) but not > > sha_ni, > > and the code that checks it is broken and misdetects sha_ni support when > > avx512 > > exists. the github runners don't have sha_ni, so it breaks exactly there. > > The code is: > > if (!shaNI) { > unsigned eax = 7, ebx = ebx, ecx = 0, edx = edx; > cpuid(&eax, &ebx, &ecx, &edx); > shaNI = ((ebx >> 29) << 1) - 1; > } > if (shaNI > 0) > ctx->process_block = sha1_process_block64_shaNI; > > If ebx's bit 29 is set, then shaNI = 1. If it is clear, then shaNI = -1. > > I checked > "Intel® 64 and IA-32 Architectures Software Developer*s Manual > Combined Volumes: 1, 2A, 2B, 2C, 2D, 3A, 3B, 3C, 3D and 4" > > to verify that CPUID(EAX=7, ECX=0) and bit position (EBX.29) > is the correct check for SHA-NI. > > I double-checked it in Linux kernel source. > > I checked disassembly and it correctly sets up registers for CPUID. > > Can someone tell me on what CPU this does not work? Github runners. I created a job where it fails. See here: You have output of cpuinfo here: https://github.com/ncopa/busybox/actions/runs/3947969708/jobs/6757415539#step:4:1 I also tried to fix it with this change, but failed: https://github.com/ncopa/busybox/commit/e4ad5e7f2fed8e36d0779d918052169fe9a0bb95 This was based on the example function `int CheckForIntelShaExtensions()` in https://www.intel.com/content/www/us/en/developer/articles/technical/intel-sha-extensions.html -nc _______________________________________________ busybox mailing list busybox@busybox.net http://lists.busybox.net/mailman/listinfo/busybox
