From: Tom Zanussi <zanussi@xxxxxxxxxx> [ Upstream commit 784bd0847eda032ed2f3522f87250655a18c0190 ] 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@xxxxxxxxxx Reported-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Tom Zanussi <zanussi@xxxxxxxxxx> Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- kernel/trace/trace_events_hist.c | 32 +++++++++++++++++++++++++++++--- 1 file changed, 29 insertions(+), 3 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index e10585ef00e15..862fb6d16edb8 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -811,6 +811,29 @@ 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) @@ -849,10 +872,13 @@ 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, " ("); -- 2.20.1
