Messages in this thread Patch in this message | | | Date | Sat, 25 Apr 2020 10:57:59 +0200 | From | Borislav Petkov <> | Subject | Re: [PATCH] x86: Fix early boot crash on gcc-10, next try |
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On Fri, Apr 24, 2020 at 09:46:57PM -0400, Arvind Sankar wrote: > The comment above boot_init_stack_canary's definition should be updated > to note that it needs to be called from a function that, in addition to > not returning, either has stackprotector disabled or avoids ending in a > tail call.
How's that?
diff --git a/arch/x86/include/asm/stackprotector.h b/arch/x86/include/asm/stackprotector.h index 91e29b6a86a5..237a54f60d6b 100644 --- a/arch/x86/include/asm/stackprotector.h +++ b/arch/x86/include/asm/stackprotector.h @@ -55,8 +55,12 @@ /* * Initialize the stackprotector canary value. * - * NOTE: this must only be called from functions that never return, - * and it must always be inlined. + * NOTE: this must only be called from functions that never return, it must + * always be inlined and it should be called from a compilation unit for + * which stack protector is disabled. + * + * Alternatively, the caller should not end with a function call which gets + * tail-call optimized as that would lead to checking a modified canary value. */ static __always_inline void boot_init_stack_canary(void) { > There are also other calls that likely need to be fixed as well -- in > init/main.c, arch/x86/xen/smp_pv.c, and there is a powerpc version of > start_secondary in arch/powerpc/kernel/smp.c which may also be affected.
Yes, there was an attempt to fix former:
https://lkml.kernel.org/r/20200413123535.10884-1-frederic.pierret@qubes-os.org
I probably should point the folks to this thread. CCed.
Boris O, Jürgen, I'm guessing I should fix cpu_bringup_and_idle() too, see:
https://lkml.kernel.org/r/20200423161126.GD26021@zn.tnic
or do you prefer a separate patch?
Thx.
-- Regards/Gruss, Boris.
https://people.kernel.org/tglx/notes-about-netiquette
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