From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
To make handling BIG and LITTLE endian better the offset/len of dynamic
fields of the synthetic events was changed into a structure of:
struct trace_dynamic_info {
#ifdef CONFIG_CPU_BIG_ENDIAN
u16 offset;
u16 len;
#else
u16 len;
u16 offset;
#endif
};
to replace the manual changes of:
data_offset = offset & 0xffff;
data_offest = len << 16;
But if you look closely, the above is:
<len> << 16 | offset
Which in little endian would be in memory:
offset_lo offset_hi len_lo len_hi
and in big endian:
len_hi len_lo offset_hi offset_lo
Which if broken into a structure would be:
struct trace_dynamic_info {
#ifdef CONFIG_CPU_BIG_ENDIAN
u16 len;
u16 offset;
#else
u16 offset;
u16 len;
#endif
};
Which is the opposite of what was defined.
Fix this and just to be safe also add "__packed".
Link: https://lore.kernel.org/all/20230908154417.5172e343@xxxxxxxxxxxxxxxxxx/
Link: https://lore.kernel.org/linux-trace-kernel/20230908163929.2c25f3dc@xxxxxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Fixes: ddeea494a16f3 ("tracing/synthetic: Use union instead of casts")
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
---
include/linux/trace_events.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h
index 12f875e9e69a..21ae37e49319 100644
--- a/include/linux/trace_events.h
+++ b/include/linux/trace_events.h
@@ -62,13 +62,13 @@ void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...);
/* Used to find the offset and length of dynamic fields in trace events */
struct trace_dynamic_info {
#ifdef CONFIG_CPU_BIG_ENDIAN
- u16 offset;
u16 len;
+ u16 offset;
#else
- u16 len;
u16 offset;
+ u16 len;
#endif
-};
+} __packed;
/*
* The trace entry - the most basic unit of tracing. This is what
--
2.40.1
