| From b0e2157420bb5acf3c1a9a14996bd38022d3b1df Mon Sep 17 00:00:00 2001 |
| From: Sven Schnelle <svens@linux.ibm.com> |
| Date: Wed, 18 Dec 2019 08:44:27 +0100 |
| Subject: [PATCH] tracing: Fix endianness bug in histogram trigger |
| |
| commit fe6e096a5bbf73a142f09c72e7aa2835026eb1a3 upstream. |
| |
| At least on PA-RISC and s390 synthetic histogram triggers are failing |
| selftests because trace_event_raw_event_synth() always writes a 64 bit |
| values, but the reader expects a field->size sized value. On little endian |
| machines this doesn't hurt, but on big endian this makes the reader always |
| read zero values. |
| |
| Link: http://lore.kernel.org/linux-trace-devel/20191218074427.96184-4-svens@linux.ibm.com |
| |
| Cc: stable@vger.kernel.org |
| Fixes: 4b147936fa509 ("tracing: Add support for 'synthetic' events") |
| Acked-by: Tom Zanussi <tom.zanussi@linux.intel.com> |
| Signed-off-by: Sven Schnelle <svens@linux.ibm.com> |
| Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c |
| index 725b9b35f933..3a03b5dd1419 100644 |
| --- a/kernel/trace/trace_events_hist.c |
| +++ b/kernel/trace/trace_events_hist.c |
| @@ -891,7 +891,26 @@ static notrace void trace_event_raw_event_synth(void *__data, |
| strscpy(str_field, str_val, STR_VAR_LEN_MAX); |
| n_u64 += STR_VAR_LEN_MAX / sizeof(u64); |
| } else { |
| - entry->fields[n_u64] = var_ref_vals[var_ref_idx + i]; |
| + struct synth_field *field = event->fields[i]; |
| + u64 val = var_ref_vals[var_ref_idx + i]; |
| + |
| + switch (field->size) { |
| + case 1: |
| + *(u8 *)&entry->fields[n_u64] = (u8)val; |
| + break; |
| + |
| + case 2: |
| + *(u16 *)&entry->fields[n_u64] = (u16)val; |
| + break; |
| + |
| + case 4: |
| + *(u32 *)&entry->fields[n_u64] = (u32)val; |
| + break; |
| + |
| + default: |
| + entry->fields[n_u64] = val; |
| + break; |
| + } |
| n_u64++; |
| } |
| } |
| -- |
| 2.7.4 |
| |
