Re: [PATCH 2/2] powerpc/text-patching: Fix possible stringop-overread compilation error

On Mon, 9 Feb 2026 14:41:51 +0100, Christophe Leroy (CS GROUP) wrote:

Le 09/02/2026 à 14:25, Xie Yuanbin a écrit :

quoted

On Fri, 6 Feb 2026 20:53:55 +0100, Christophe Leroy (CS GROUP) wrote:

quoted

ppc_kallsyms_lookup_name() only has two callers and they call it with a
built-in string. I think we can do something a lot simpler, something
like (untested):

static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
	unsigned long addr = kallsyms_lookup_name(name);

	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
		addr = ppc_function_entry((void *)addr);

	return addr;
}

#ifdef CONFIG_PPC64_ELF_ABI_V1
#define ppc_kallsyms_lookup_name(x)	__ppc_kallsyms_lookup_name("." ## x);
#else
#define ppc_kallsyms_lookup_name(x)	__ppc_kallsyms_lookup_name(x)
#endif

Christophe

When CONFIG_PPC64_ELF_ABI_V1=y, it seems that the try of lookupinp
the original non-dot symbol is missing.

What about this (Only the compilation test is performed):

static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
	unsigned long addr = kallsyms_lookup_name(name);

	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
		addr = ppc_function_entry((void *)addr);

	return addr;
}

#define ppc_kallsyms_lookup_name(x) ({					\
		unsigned long addr = 0;					\
		if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1))		\
			addr = __ppc_kallsyms_lookup_name("." x);	\
		if (!addr)						\
			addr = __ppc_kallsyms_lookup_name(x);		\
		addr;							\
	})

Good point.

To avoid duplicating the string I'd suggest:

static inline unsigned long __ppc_kallsyms_lookup_name(const char *name)
{
	unsigned long addr = kallsyms_lookup_name(name);

	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V1) && !addr)
		addr = kallsyms_lookup_name(name + 1);
	if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && addr)
		addr = ppc_function_entry((void *)addr);

	return addr;
}

#ifdef CONFIG_PPC64_ELF_ABI_V1
#define ppc_kallsyms_lookup_name(x)	__ppc_kallsyms_lookup_name("." x);
#else
#define ppc_kallsyms_lookup_name(x)	__ppc_kallsyms_lookup_name(x)
#endif

This seems good, but there seems to be an extra ';' after
'__ppc_kallsyms_lookup_name("." x)' ?

After removing the extra ';', I performed a compilation test,
no warnings.