lkml.org 
[lkml]   [2019]   [Jul]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
SubjectRe: objtool crashes on clang output (drivers/hwmon/pmbus/adm1275.o)
On Thu, Jul 11, 2019 at 02:40:06PM +0200, Arnd Bergmann wrote:
> During randconfig testing with clang-9, I came across an object file
> that makes objtool segfault, see attachment. Let me know if you need
> more information to
> debug this.
>
> I also get a ton of objtool warnings building random configurations, but Nick
> mentioned that there is still a bug related to asm-goto in the build I'm using
> that may be the root cause. Once I have a fixed clang-9 build, I can have a look
> at those as well.

Seg fault fix:

diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index 27818a93f0b1..ad18f8ef905a 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -902,7 +902,7 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn,
struct rela *table, struct rela *next_table)
{
struct rela *rela = table;
- struct instruction *alt_insn;
+ struct instruction *alt_insn, *prev_insn;
struct alternative *alt;
struct symbol *pfunc = insn->func->pfunc;
unsigned int prev_offset = 0;
@@ -924,6 +924,20 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn,
if (!alt_insn)
break;

+ if (!alt_insn->func) {
+ /*
+ * Clang 9 has a quirk where a switch table may have
+ * unused entries in the middle of the table which
+ * point to just past the end of the function. They're
+ * still part of the table but can be ignored.
+ */
+ prev_insn = list_prev_entry(alt_insn, list);
+ if (prev_insn->func && prev_insn->func->pfunc == pfunc)
+ goto skip;
+
+ break;
+ }
+
/* Make sure the jmp dest is in the function or subfunction: */
if (alt_insn->func->pfunc != pfunc)
break;
@@ -936,6 +950,7 @@ static int add_switch_table(struct objtool_file *file, struct instruction *insn,

alt->insn = alt_insn;
list_add_tail(&alt->list, &insn->alts);
+skip:
prev_offset = rela->offset;
}

\
 
 \ /
  Last update: 2019-07-11 19:27    [W:0.042 / U:1.808 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site