kfence: fix reports if constant function prefixes exist

Some architectures prefix all functions with a constant string ('.' on ppc64). Add ARCH_FUNC_PREFIX, which may optionally be defined in <asm/kfence.h>, so that get_stack_skipnr() can work properly. Link: https://lkml.kernel.org/r/[email protected] Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Marco Elver <[email protected]> Reported-by: Christophe Leroy <[email protected]> Tested-by: Christophe Leroy <[email protected]> Cc: Alexander Potapenko <[email protected]> Cc: Dmitry Vyukov <[email protected]> Cc: Andrey Konovalov <[email protected]> Cc: Jann Horn <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
tadfisher · Mar 13, 2021 · 0aa41ca · 0aa41ca
1 parent df3ae2c
commit 0aa41ca
Showing 1 changed file with 12 additions and 6 deletions.
diff --git a/mm/kfence/report.c b/mm/kfence/report.c
@@ -20,6 +20,11 @@
 
 #include "kfence.h"
 
+/* May be overridden by <asm/kfence.h>. */
+#ifndef ARCH_FUNC_PREFIX
+#define ARCH_FUNC_PREFIX ""
+#endif
+
 extern bool no_hash_pointers;
 
 /* Helper function to either print to a seq_file or to console. */
@@ -67,8 +72,9 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries
 	for (skipnr = 0; skipnr < num_entries; skipnr++) {
 		int len = scnprintf(buf, sizeof(buf), "%ps", (void *)stack_entries[skipnr]);
 
-		if (str_has_prefix(buf, "kfence_") || str_has_prefix(buf, "__kfence_") ||
-		    !strncmp(buf, "__slab_free", len)) {
+		if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfence_") ||
+		    str_has_prefix(buf, ARCH_FUNC_PREFIX "__kfence_") ||
+		    !strncmp(buf, ARCH_FUNC_PREFIX "__slab_free", len)) {
 			/*
 			 * In case of tail calls from any of the below
 			 * to any of the above.
@@ -77,10 +83,10 @@ static int get_stack_skipnr(const unsigned long stack_entries[], int num_entries
 		}
 
 		/* Also the *_bulk() variants by only checking prefixes. */
-		if (str_has_prefix(buf, "kfree") ||
-		    str_has_prefix(buf, "kmem_cache_free") ||
-		    str_has_prefix(buf, "__kmalloc") ||
-		    str_has_prefix(buf, "kmem_cache_alloc"))
+		if (str_has_prefix(buf, ARCH_FUNC_PREFIX "kfree") ||
+		    str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_free") ||
+		    str_has_prefix(buf, ARCH_FUNC_PREFIX "__kmalloc") ||
+		    str_has_prefix(buf, ARCH_FUNC_PREFIX "kmem_cache_alloc"))
 			goto found;
 	}
 	if (fallback < num_entries)