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

[Sasha Levin]

From: Zhengjun Xing <zhengjun.xing@xxxxxxxxxxxxxxx>

[ 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@xxxxxxxxxxxxxxx

Reviewed-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
Signed-off-by: Zhengjun Xing <zhengjun.xing@xxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 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