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-rw-r--r--include/trace/ftrace.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index a05524fa245..f64fbaae781 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -648,6 +648,9 @@ __attribute__((section("_ftrace_events"))) event_##call = { \
* char raw_data[__entry_size]; <- allocate our sample in the stack
* struct trace_entry *ent;
*
+ * zero dead bytes from alignment to avoid stack leak to userspace:
+ *
+ * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL;
* entry = (struct ftrace_raw_<call> *)raw_data;
* ent = &entry->ent;
* tracing_generic_entry_update(ent, irq_flags, pc);
@@ -698,6 +701,7 @@ static void ftrace_profile_##call(proto) \
char raw_data[__entry_size]; \
struct trace_entry *ent; \
\
+ *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; \
entry = (struct ftrace_raw_##call *)raw_data; \
ent = &entry->ent; \
tracing_generic_entry_update(ent, irq_flags, pc); \