[CRIU] [PATCH 3/4] vdso: Rework vdso processing files

[Christopher Covington]

On 09/15/2015 11:14 AM, Laurent Dufour wrote:
> On 15/09/2015 17:01, Christopher Covington wrote:
>> On 09/15/2015 09:54 AM, Christopher Covington wrote:
>>
>>>> -int vdso_fill_symtable(char *mem, size_t size, struct vdso_symtable *t)
>>>> -{
>>>> -	Elf64_Phdr *dynamic = NULL, *load = NULL;
>>>> -	Elf64_Ehdr *ehdr = (void *)mem;
>>>> -	Elf64_Dyn *dyn_strtab = NULL;
>>>> -	Elf64_Dyn *dyn_symtab = NULL;
>>>> -	Elf64_Dyn *dyn_strsz = NULL;
>>>> -	Elf64_Dyn *dyn_syment = NULL;
>>>> -	Elf64_Dyn *dyn_hash = NULL;
>>>> -	Elf64_Word *hash = NULL;
>>>> -	Elf64_Phdr *phdr;
>>>> -	Elf64_Dyn *d;
>>>> -
>>>> -	Elf64_Word *bucket, *chain;
>>>> -	Elf64_Word nbucket, nchain;
>>>> -
>>>> -	/*
>>>> -	 * See Elf specification for this magic values.
>>>> -	 */
>>>> -	const char elf_ident[] = {
>>>> -		0x7f, 0x45, 0x4c, 0x46, 0x02, 0x01, 0x01, 0x00,
>>>> -		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
>>>> -	};
>>>> -
>>>> -	const char *vdso_symbols[VDSO_SYMBOL_MAX] = {
>>>> -		[VDSO_SYMBOL_CLOCK_GETRES]	= VDSO_SYMBOL_CLOCK_GETRES_NAME,
>>>> -		[VDSO_SYMBOL_CLOCK_GETTIME]	= VDSO_SYMBOL_CLOCK_GETTIME_NAME,
>>>> -		[VDSO_SYMBOL_GETTIMEOFDAY]	= VDSO_SYMBOL_GETTIMEOFDAY_NAME,
>>>> -		[VDSO_SYMBOL_RT_SIGRETURN]	= VDSO_SYMBOL_RT_SIGRETURN_NAME,
>>>> -	};
>>
>> It looks like making vdso_symbols global was the problem. Any objections to
>> moving the definition (the version that uses architecture-provided macro
>> ARCH_VDSO_SYMBOLS) inside the vdso_fill_symtable function?
> 
> The main objection here is the stack's usage, but this table is not so
> big so...

On this point, it's const, so I didn't expect it to be allocated on the stack.

> Anyway, my fear here is that this hiding a more complex issue relative
> to the PIE's code and the underlying relocation. Isn't it ?

That could be.

Christopher Covington

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