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authorSteven Rostedt (Google) <rostedt@goodmis.org>2023-09-08 16:39:29 -0400
committerSteven Rostedt (Google) <rostedt@goodmis.org>2023-09-11 18:22:00 -0400
commitfc52a64416b010c8324e2cb50070faae868521c1 (patch)
tree2e20465d3523ecf12d49598b025e71311637180d /include/linux/trace_events.h
parent145036f88d693d7ef3aa8537a4b1aa22f8764647 (diff)
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: <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@gandalf.local.home/ Link: https://lore.kernel.org/linux-trace-kernel/20230908163929.2c25f3dc@gandalf.local.home Cc: stable@vger.kernel.org Cc: Mark Rutland <mark.rutland@arm.com> Tested-by: Sven Schnelle <svens@linux.ibm.com> Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Fixes: ddeea494a16f3 ("tracing/synthetic: Use union instead of casts") Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Diffstat (limited to 'include/linux/trace_events.h')
-rw-r--r--include/linux/trace_events.h6
1 files 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