trace: fix multiple use of __print_flags and __print_symbolic

From: Steven Whitehouse
Date: Wed Jun 03 2009 - 05:05:41 EST



When using multiple calls to __print_symbolic and __print_flags in
the same tracer, I noticed that the output was incorrect. I think
the following patch is the correct fix (it works for me) but please
check it carefully since I'm not that familiar with this code,
and I may well have made a mistake somewhere.

The patch is vs. the latest -tip tree which doesn't yet seem to
contain the EXPORT_SYMBOL() fix that I sent earlier.

Signed-off-by: Steven Whitehouse <swhiteho@xxxxxxxxxx>


diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index c12d95d..ac6ced1 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -222,10 +222,9 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim,
{
unsigned long mask;
const char *str;
+ const char *ret = p->buffer + p->len;
int i;

- trace_seq_init(p);
-
for (i = 0; flag_array[i].name && flags; i++) {

mask = flag_array[i].mask;
@@ -248,7 +247,7 @@ ftrace_print_flags_seq(struct trace_seq *p, const char *delim,

trace_seq_putc(p, 0);

- return p->buffer;
+ return ret;
}

const char *
@@ -256,8 +255,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,
const struct trace_print_flags *symbol_array)
{
int i;
-
- trace_seq_init(p);
+ const char *ret = p->buffer + p->len;

for (i = 0; symbol_array[i].name; i++) {

@@ -273,7 +271,7 @@ ftrace_print_symbols_seq(struct trace_seq *p, unsigned long val,

trace_seq_putc(p, 0);

- return p->buffer;
+ return ret;
}

#ifdef CONFIG_KRETPROBES


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/