Messages in this thread | | | Subject | Re: [PATCH] x86: Fix early boot crash on gcc-10, next try | From | Jürgen Groß <> | Date | Sat, 25 Apr 2020 13:09:53 +0200 |
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On 25.04.20 10:57, Borislav Petkov wrote: > 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?
I'm fine with you including it in your patch.
Juergen
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