From fc52a64416b010c8324e2cb50070faae868521c1 Mon Sep 17 00:00:00 2001 From: "Steven Rostedt (Google)" Date: Fri, 8 Sep 2023 16:39:29 -0400 Subject: tracing/synthetic: Fix order of struct trace_dynamic_info 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: << 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@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20230908163929.2c25f3dc@gandalf.local.home Cc: stable@vger.kernel.org Cc: Mark Rutland Tested-by: Sven Schnelle Acked-by: Masami Hiramatsu (Google) Fixes: ddeea494a16f3 ("tracing/synthetic: Use union instead of casts") Signed-off-by: Steven Rostedt (Google) --- include/linux/trace_events.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux/trace_events.h') 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 -- cgit