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SubjectRe: Out-of-bounds access in vread_hpet()
On Mon, Jun 9, 2014 at 11:36 PM, Richard Weinberger <richard@nod.at> wrote:
> FYI:
> ________________________________________________________________________________________________________
> *** CID 1222081: Out-of-bounds access (ARRAY_VS_SINGLETON)
> /arch/x86/vdso/vclock_gettime.c: 38 in vread_hpet()
> 32 #ifdef CONFIG_HPET_TIMER
> 33 extern u8 hpet_page
> 34 __attribute__((visibility("hidden")));
> 35
> 36 static notrace cycle_t vread_hpet(void)
> 37 {
>>>> CID 1222081: Out-of-bounds access (ARRAY_VS_SINGLETON)
>>>> Using "&hpet_page" as an array. This might corrupt or misinterpret adjacent memory locations.
> 38 return *(const volatile u32 *)(&hpet_page + HPET_COUNTER);

That's a false positive. HPET_COUNTER is a compile-time constant
index of a register, and hpet_page is the base address where the thing
is mapped.

I can change the code if there's something non-ugly that makes it
clearer, but ISTM that this particular warning might not make so much
sense when the offset is a real constant like this.

Hmm. Maybe hpet_page could be redefined as const char hpet_page[PAGE_SIZE].

--Andy


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