diff options
| author | Tom Zanussi <zanussi@kernel.org> | 2020-02-14 16:56:41 -0600 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2020-02-20 16:24:17 -0500 |
| commit | 784bd0847eda032ed2f3522f87250655a18c0190 (patch) | |
| tree | 259ac748d1cc825aaf13b8eb5d2c3630f458b2f7 /kernel/trace/trace_events_hist.c | |
| parent | 3843083772dc2afde790a6d7160658b00a808da1 (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.c | 32 |
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, " ("); |