Messages in this thread | | | Date | Thu, 10 Aug 2023 10:10:38 +0200 | From | Borislav Petkov <> | Subject | Re: Hang when booting guest kernels compiled with clang after SRSO mitigations |
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On Wed, Aug 09, 2023 at 06:33:34PM -0700, Nathan Chancellor wrote: > Hi Boris, > > I updated my AMD 3990X workstation to a version of mainline that > contains the SRSO mitigations and I am now seeing a hang when booting > guest kernels built with clang in QEMU/KVM with an '-smp' value greater > than one (I am just testing 'ARCH=x86_64 defconfig', nothing fancy). The > host's kernel is built with GCC 13.2.0, in case that is relevant. The > issue happens with all versions of clang that the kernel supports > (11.x+). I do not see the issue with guest kernels built with GCC nor do > I see the issue with '-smp 1', so it could be something that clang has > done to the guest kernel that causes this but I figured I would report > it early anyways. > > With '-smp 4' (for example), I see > > [ 0.102817] smpboot: CPU0: AMD Ryzen Threadripper 3990X 64-Core Processor (family: 0x17, model: 0x31, stepping: 0x0) > ... > [ 0.109778] smp: Bringing up secondary CPUs ... > [ 0.110559] smpboot: x86: Booting SMP configuration:
I can repro this here with Debian clang version 14.0.6-2 even with -smp 2.
Lemme poke at this a bit.
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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