lkml.org 
[lkml]   [2008]   [Oct]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [patch] clean hex output of ftrace
From
Date
On Wed, 2008-10-08 at 17:16 -0700, Joe Perches wrote:
> On Wed, 8 Oct 2008, Harvey Harrison wrote:
> > From: Harvey Harrison <harvey.harrison@gmail.com>
> > Subject: [PATCH] ftrace: Fix inversion of hex output and use common routines
>
> You're quick...
>
> > BUG_ON(len >= HEX_CHARS);
>
> I think the BUG_ON is senseless.
>

Agreed, it probably meant to say BUG_ON(len * 2 > HEX_CHARS -1)

But as this is only called from within a helper macro, it could be
changed to a build-time check instead of a runtime:

From: Harvey Harrison <harvey.harrison@gmail.com>
Subject: [PATCH] trace: add build-time check to avoid overrunning hex buffer

Remove the runtime BUG_ON and change to a compile-time check in
the macro that calls the hex format routine

[Noticed by Joe Perches]
Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com>
---
kernel/trace/trace.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 763f763..1ffbc24 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -395,7 +395,8 @@ trace_seq_putmem(struct trace_seq *s, void *mem, size_t len)
return len;
}

-#define HEX_CHARS 17
+#define MAX_MEMHEX_BYTES (8)
+#define HEX_CHARS ((MAX_MEMHEX_BYTES * 2) + 1)

static int
trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
@@ -404,8 +405,6 @@ trace_seq_putmem_hex(struct trace_seq *s, void *mem, size_t len)
unsigned char *data = mem;
int i, j;

- BUG_ON(len >= HEX_CHARS);
-
#ifdef __BIG_ENDIAN
for (i = 0, j = 0; i < len; i++) {
#else
@@ -1706,6 +1705,7 @@ do { \

#define SEQ_PUT_HEX_FIELD_RET(s, x) \
do { \
+ BUILD_BUG_ON(sizeof(x) > MAX_MEMHEX_BYTES); \
if (!trace_seq_putmem_hex(s, &(x), sizeof(x))) \
return 0; \
} while (0)
--
1.6.0.2.471.g47a76




\
 
 \ /
  Last update: 2008-10-09 02:49    [W:0.027 / U:3.532 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site