lkml.org 
[lkml]   [2021]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2] kallsyms: strip ThinLTO postfix ".cfi_jt"
Date
Clang ThinLTO adds a postfix ".cfi_jt" to a symbols of extern functions.
For example this breaks syscall tracer that doesn't expect such postfix,
so strip out the postfix from the output.

Signed-off-by: Padmanabha Srinivasaiah <treasure4paddy@gmail.com>
---
Change in v2:
- Use existing routine in kallsyms to strip postfix ".cfi_jt" from
extern function name.
- Modified the commit message accordingly

kernel/kallsyms.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 0ba87982d017..e9148626ae6c 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -166,16 +166,20 @@ static unsigned long kallsyms_sym_address(int idx)

#if defined(CONFIG_CFI_CLANG) && defined(CONFIG_LTO_CLANG_THIN)
/*
- * LLVM appends a hash to static function names when ThinLTO and CFI are
- * both enabled, i.e. foo() becomes foo$707af9a22804d33c81801f27dcfe489b.
- * This causes confusion and potentially breaks user space tools, so we
- * strip the suffix from expanded symbol names.
+ * LLVM appends a hash to static function names and just ".cfi_jt" postfix
+ * for non-static functions when both ThinLTO and CFI are enabled,
+ * i.e. for example foo() becomes foo$707af9a22804d33c81801f27dcfe489b.
+ * This causes confusion and potentially breaks user space tools and
+ * built-in components, so we strip the suffix from expanded symbol names.
*/
static inline bool cleanup_symbol_name(char *s)
{
char *res;

res = strrchr(s, '$');
+ if (!res)
+ res = strstr(s, ".cfi_jt");
+
if (res)
*res = '\0';

--
2.17.1
\
 
 \ /
  Last update: 2021-07-27 16:08    [W:0.107 / U:0.192 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site