Messages in this thread | | | Subject | Re: [PATCH] tracing/filters: use strcmp() instead of strncmp() | From | Steven Rostedt <> | Date | Mon, 07 Sep 2009 22:48:21 -0400 |
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Li,
I'm going through some old email, and I came across this patch. It seems that it never got applied. Could you port this to the latest -tip tree and resend it.
Sorry about missing it.
Thanks,
-- Steve
On Sun, 2009-05-31 at 13:53 +0800, Li Zefan wrote: > Trace filter is not working normally: > > # echo 'name == et' > tracing/events/irq/irq_handler_entry/filter > # echo 1 > tracing/events/irq/irq_handler_entry/enable > # cat trace_pipe > <idle>-0 [001] 1363.423175: irq_handler_entry: irq=18 handler=eth0 > <idle>-0 [001] 1363.934528: irq_handler_entry: irq=18 handler=eth0 > > It's because we pass to trace_define_field() the information of > __str_loc_##item, but not the actual string, so pred->str_len == field->size > == sizeof(unsigned short), thus it always compare at most 2 bytes when > filtering on __string() field. > > Since __string() is dynamic size, we are not able to set field->size to > string length. Alternatively this patch uses strcmp() instead of strncmp(), > for both static strings and dynamic strings. strncmp() is not necessary, > since strings passed to it are already guaranteed to be NULL-terminated. > > [ Impact: make filter facility working normally for dynamic strings ] > > Signed-off-by: Li Zefan <lizf@cn.fujitsu.com> > --- > kernel/trace/trace.h | 1 - > kernel/trace/trace_events_filter.c | 7 ++----- > 2 files changed, 2 insertions(+), 6 deletions(-) > > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 6e735d4..ec8970b 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -758,7 +758,6 @@ struct filter_pred { > filter_pred_fn_t fn; > u64 val; > char str_val[MAX_FILTER_STR_VAL]; > - int str_len; > char *field_name; > int offset; > int not; > diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c > index a854eed..8362586 100644 > --- a/kernel/trace/trace_events_filter.c > +++ b/kernel/trace/trace_events_filter.c > @@ -158,7 +158,7 @@ static int filter_pred_string(struct filter_pred *pred, void *event, > char *addr = (char *)(event + pred->offset); > int cmp, match; > > - cmp = strncmp(addr, pred->str_val, pred->str_len); > + cmp = strcmp(addr, pred->str_val); > > match = (!cmp) ^ pred->not; > > @@ -182,7 +182,7 @@ static int filter_pred_strloc(struct filter_pred *pred, void *event, > char *addr = (char *)(event + str_loc); > int cmp, match; > > - cmp = strncmp(addr, pred->str_val, pred->str_len); > + cmp = strcmp(addr, pred->str_val); > > match = (!cmp) ^ pred->not; > > @@ -341,7 +341,6 @@ static void filter_clear_pred(struct filter_pred *pred) > { > kfree(pred->field_name); > pred->field_name = NULL; > - pred->str_len = 0; > } > > static int filter_set_pred(struct filter_pred *dest, > @@ -576,7 +575,6 @@ static int filter_add_pred(struct filter_parse_state *ps, > fn = filter_pred_string; > else > fn = filter_pred_strloc; > - pred->str_len = field->size; > if (pred->op == OP_NE) > pred->not = 1; > return filter_add_pred_fn(ps, call, pred, fn); > @@ -957,7 +955,6 @@ static struct filter_pred *create_pred(int op, char *operand1, char *operand2) > } > > strcpy(pred->str_val, operand2); > - pred->str_len = strlen(operand2); > > pred->op = op; >
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