Messages in this thread | ![/](/images/icornerl.gif) | | Date | Thu, 19 Jan 2023 16:18:34 +0100 | From | Peter Zijlstra <> | Subject | Re: [bisected] clang 15 built kernel fails to boot, stuck at "Loading Linux 6.1.1 ...", gcc 12 built kernel with same config boots fine |
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On Thu, Jan 19, 2023 at 02:56:08PM +0100, Peter Zijlstra wrote: > On Thu, Jan 19, 2023 at 02:23:03AM +0100, Erhard F. wrote: > > Hi! > > > > I did a kernel bisect for an issue I originally posted on https://github.com/ClangBuiltLinux/linux/issues/1774 > > > > It is about kernel 6.1.x not booting on my machines when built with clang. A gcc built kernel with the same config just works fine. Turns out kernel v6.2-rc4 and earlier v6.2-rc are still affected. > > > > I did a kernel bisect which revealed this commit: > > > > # git bisect bad > > 706460a96fc654e80b6bed1f562b00d2ce9f2f4d is the first bad commit > > commit 706460a96fc654e80b6bed1f562b00d2ce9f2f4d > > Author: Sandipan Das <sandipan.das@amd.com> > > Date: Thu Aug 11 17:59:51 2022 +0530 > > > > perf/x86/amd/core: Add generic branch record interfaces > > > > AMD processors that are capable of recording branches support either Branch > > Sampling (BRS) or Last Branch Record (LBR). In preparation for adding Last > > Branch Record Extension Version 2 (LbrExtV2) support, introduce new static > > calls which act as gateways to call into the feature-dependent functions > > based on what is available on the processor. > > > > Signed-off-by: Sandipan Das <sandipan.das@amd.com> > > Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> > > Link: https://lore.kernel.org/r/b75dbc32663cb395f0d701167e952c6a6b0445a3.1660211399.git.sandipan.das@amd.com > > > > arch/x86/events/amd/core.c | 34 ++++++++++++++++++++++------------ > > 1 file changed, 22 insertions(+), 12 deletions(-) > > Using: v6.2-rc4-67-g7287904c8771 > > I have an AMD Interlagos and after bringing it back to live/up-to-date I > can't seem to even boot your .config in qemu/kvm irrespective of > GCC/Clang. > > When I build defconfig+kvm_guest.config both GCC-12 and clang-15 boot > just fine in qemu/kvm.
Furthermore, testing localyesconfig based off Debian's config-6.1.0-1-amd64 boots fine using both GCC-12 and clang-15 as host kernels on that machine.
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