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authorTom Zanussi <zanussi@kernel.org>2020-02-14 16:56:41 -0600
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-02-20 16:24:17 -0500
commit784bd0847eda032ed2f3522f87250655a18c0190 (patch)
tree259ac748d1cc825aaf13b8eb5d2c3630f458b2f7 /kernel/trace/trace_events_hist.c
parent3843083772dc2afde790a6d7160658b00a808da1 (diff)
tracing: Fix number printing bug in print_synth_event()
Fix a varargs-related bug in print_synth_event() which resulted in strange output and oopses on 32-bit x86 systems. The problem is that trace_seq_printf() expects the varargs to match the format string, but print_synth_event() was always passing u64 values regardless. This results in unspecified behavior when unpacking with va_arg() in trace_seq_printf(). Add a function that takes the size into account when calling trace_seq_printf(). Before: modprobe-1731 [003] .... 919.039758: gen_synth_test: next_pid_field=777(null)next_comm_field=hula hoops ts_ns=1000000 ts_ms=1000 cpu=3(null)my_string_field=thneed my_int_field=598(null) After: insmod-1136 [001] .... 36.634590: gen_synth_test: next_pid_field=777 next_comm_field=hula hoops ts_ns=1000000 ts_ms=1000 cpu=1 my_string_field=thneed my_int_field=598 Link: http://lkml.kernel.org/r/a9b59eb515dbbd7d4abe53b347dccf7a8e285657.1581720155.git.zanussi@kernel.org Reported-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Tom Zanussi <zanussi@kernel.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_events_hist.c')
-rw-r--r--kernel/trace/trace_events_hist.c32
1 files changed, 29 insertions, 3 deletions
diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index 45622194a34d..f068d55bd37f 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -820,6 +820,29 @@ static const char *synth_field_fmt(char *type)
return fmt;
}
+static void print_synth_event_num_val(struct trace_seq *s,
+ char *print_fmt, char *name,
+ int size, u64 val, char *space)
+{
+ switch (size) {
+ case 1:
+ trace_seq_printf(s, print_fmt, name, (u8)val, space);
+ break;
+
+ case 2:
+ trace_seq_printf(s, print_fmt, name, (u16)val, space);
+ break;
+
+ case 4:
+ trace_seq_printf(s, print_fmt, name, (u32)val, space);
+ break;
+
+ default:
+ trace_seq_printf(s, print_fmt, name, val, space);
+ break;
+ }
+}
+
static enum print_line_t print_synth_event(struct trace_iterator *iter,
int flags,
struct trace_event *event)
@@ -858,10 +881,13 @@ static enum print_line_t print_synth_event(struct trace_iterator *iter,
} else {
struct trace_print_flags __flags[] = {
__def_gfpflag_names, {-1, NULL} };
+ char *space = (i == se->n_fields - 1 ? "" : " ");
- trace_seq_printf(s, print_fmt, se->fields[i]->name,
- entry->fields[n_u64],
- i == se->n_fields - 1 ? "" : " ");
+ print_synth_event_num_val(s, print_fmt,
+ se->fields[i]->name,
+ se->fields[i]->size,
+ entry->fields[n_u64],
+ space);
if (strcmp(se->fields[i]->type, "gfp_t") == 0) {
trace_seq_puts(s, " (");