[S390] s390dbf: Add description for usage of "%s" in sprintf events

Using "%s" in sprintf event functions is dangerous. This patch adds a short
description for this issue to the s390 debug feature documentation.

Signed-off-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/arch/s390/include/asm/debug.h b/arch/s390/include/asm/debug.h
index 31ed5686a968..18124b75a7ab 100644
--- a/arch/s390/include/asm/debug.h
+++ b/arch/s390/include/asm/debug.h
@@ -167,6 +167,10 @@ debug_text_event(debug_info_t* id, int level, const char* txt)
         return debug_event_common(id,level,txt,strlen(txt));
 }
 
+/*
+ * IMPORTANT: Use "%s" in sprintf format strings with care! Only pointers are
+ * stored in the s390dbf. See Documentation/s390/s390dbf.txt for more details!
+ */
 extern debug_entry_t *
 debug_sprintf_event(debug_info_t* id,int level,char *string,...)
         __attribute__ ((format(printf, 3, 4)));
@@ -206,7 +210,10 @@ debug_text_exception(debug_info_t* id, int level, const char* txt)
         return debug_exception_common(id,level,txt,strlen(txt));
 }
 
-
+/*
+ * IMPORTANT: Use "%s" in sprintf format strings with care! Only pointers are
+ * stored in the s390dbf. See Documentation/s390/s390dbf.txt for more details!
+ */
 extern debug_entry_t *
 debug_sprintf_exception(debug_info_t* id,int level,char *string,...)
         __attribute__ ((format(printf, 3, 4)));