diff mbox series

powerpc/prom_init: Fix build failure with GCC_PLUGIN_STRUCTLEAK_BYREF_ALL and KASAN

Message ID 3802811f7cf94f730be44688539c01bba3a3b5c0.1654875808.git.christophe.leroy@csgroup.eu (mailing list archive)
State Accepted
Headers show
Series powerpc/prom_init: Fix build failure with GCC_PLUGIN_STRUCTLEAK_BYREF_ALL and KASAN | expand

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Commit Message

Christophe Leroy June 10, 2022, 3:43 p.m. UTC 
When CONFIG_KASAN is selected, we expect prom_init to use __memset()
because it is too early to use memset().

But with CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL, the compiler adds calls
to memset() to clear objects on stack, hence the following failure:

	  PROMCHK arch/powerpc/kernel/prom_init_check
	Error: External symbol 'memset' referenced from prom_init.c
	make[2]: *** [arch/powerpc/kernel/Makefile:204 : arch/powerpc/kernel/prom_init_check] Erreur 1

prom_find_machine_type() is called from prom_init() and is called only
once, so lets put compat[] in BSS instead of stack to avoid that.

Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
---
 arch/powerpc/kernel/prom_init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michael Ellerman June 26, 2022, 12:28 a.m. UTC | #1 
On Fri, 10 Jun 2022 17:43:43 +0200, Christophe Leroy wrote:
> When CONFIG_KASAN is selected, we expect prom_init to use __memset()
> because it is too early to use memset().
> 
> But with CONFIG_GCC_PLUGIN_STRUCTLEAK_BYREF_ALL, the compiler adds calls
> to memset() to clear objects on stack, hence the following failure:
> 
> 	  PROMCHK arch/powerpc/kernel/prom_init_check
> 	Error: External symbol 'memset' referenced from prom_init.c
> 	make[2]: *** [arch/powerpc/kernel/Makefile:204 : arch/powerpc/kernel/prom_init_check] Erreur 1
> 
> [...]

Applied to powerpc/fixes.

[1/1] powerpc/prom_init: Fix build failure with GCC_PLUGIN_STRUCTLEAK_BYREF_ALL and KASAN
      https://git.kernel.org/powerpc/c/ca5dabcff1df6bc8c413922b5fa63cc602858803

cheers
diff mbox series

Patch

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 04694ec423f6..13d6cb188835 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -2302,7 +2302,7 @@  static void __init prom_init_stdout(void)
 
 static int __init prom_find_machine_type(void)
 {
-	char compat[256];
+	static char compat[256] __prombss;
 	int len, i = 0;
 #ifdef CONFIG_PPC64
 	phandle rtas;