parse-events: Fix unaligned accesses while fetching trace values

Accessing trace values of an 8 size may end up in a segfault
on archs that can't deal with misaligned access, which is the
case for sparc 64. This is because PERF_SAMPLE_RAW are aligned
to 4 and not to 8.

Fix this on the macros that get the values of 8 size.

This fixes segfaults on perf tools in sparc 64.

[ Got permission from Frederic to include this for LGPL trace-cmd ]

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <1274348659-15417-4-git-send-regression-fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

1 files changed, 7 insertions, 1 deletions

diff --git a/parse-events.h b/parse-events.h
index 7d1c42e..be28245 100644
--- a/parse-events.h
+++ b/parse-events.h
@@ -403,7 +403,13 @@ __data2host8(struct pevent *pevent, unsigned long long data)
 
 #define data2host2(pevent, ptr)         __data2host2(pevent, *(unsigned short *)(ptr))
 #define data2host4(pevent, ptr)         __data2host4(pevent, *(unsigned int *)(ptr))
-#define data2host8(pevent, ptr)         __data2host8(pevent, *(unsigned long long *)(ptr))
+#define data2host8(pevent, ptr)                                 \
+({                                                              \
+        unsigned long long __val;                               \
+                                                                \
+        memcpy(&__val, (ptr), sizeof(unsigned long long));      \
+        __data2host8(pevent, __val);                            \
+})
 
 /* taken from kernel/trace/trace.h */
 enum trace_flag_type {