[PATCH AUTOSEL 4.19 27/38] tracing: Fix "gfp_t" format for synthetic events

Sasha Levin
2019-10-30T15:55:27Z

From: Zhengjun Xing <zhengjun.xing@linux.intel.com>

[ Upstream commit 9fa8c9c647be624e91b09ecffa7cd97ee0600b40 ]

In the format of synthetic events, the "gfp_t" is shown as "signed:1",
but in fact the "gfp_t" is "unsigned", should be shown as "signed:0".

The issue can be reproduced by the following commands:

echo 'memlatency u64 lat; unsigned int order; gfp_t gfp_flags; int migratetype' > /sys/kernel/debug/tracing/synthetic_events
cat /sys/kernel/debug/tracing/events/synthetic/memlatency/format

name: memlatency
ID: 2233
format:
field:unsigned short common_type; offset:0; size:2; signed:0;
field:unsigned char common_flags; offset:2; size:1; signed:0;
field:unsigned char common_preempt_count; offset:3; size:1; signed:0;
field:int common_pid; offset:4; size:4; signed:1;

field:u64 lat; offset:8; size:8; signed:0;
field:unsigned int order; offset:16; size:4; signed:0;
field:gfp_t gfp_flags; offset:24; size:4; signed:1;
field:int migratetype; offset:32; size:4; signed:1;

print fmt: "lat=%llu, order=%u, gfp_flags=%x, migratetype=%d", REC->lat, REC->order, REC->gfp_flags, REC->migratetype

Link: http://lkml.kernel.org/r/20191018012034.6404-1-zhengjun.xing@linux.intel.com

Reviewed-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/trace/trace_events_hist.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c
index bdf104596d122..dac518977e7d0 100644
--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -448,6 +448,8 @@ static bool synth_field_signed(char *type)
{
if (strncmp(type, "u", 1) == 0)
return false;
+ if (strcmp(type, "gfp_t") == 0)
+ return false;

return true;
}
--
2.20.1