Messages in this thread Patch in this message | | | Subject | Re: [patch] clean hex output of ftrace | From | Harvey Harrison <> | Date | Wed, 08 Oct 2008 17:44:55 -0700 |
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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
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