Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits)
  perf_counter: Zero dead bytes from ftrace raw samples size alignment
  perf_counter: Subtract the buffer size field from the event record size
  perf_counter: Require CAP_SYS_ADMIN for raw tracepoint data
  perf_counter: Correct PERF_SAMPLE_RAW output
  perf tools: callchain: Fix bad rounding of minimum rate
  perf_counter tools: Fix libbfd detection for systems with libz dependency
  perf: "Longum est iter per praecepta, breve et efficax per exempla"
  perf_counter: Fix a race on perf_counter_ctx
  perf_counter: Fix tracepoint sampling to be part of generic sampling
  perf_counter: Work around gcc warning by initializing tracepoint record unconditionally
  perf tools: callchain: Fix sum of percentages to be 100% by displaying amount of ignored chains in fractal mode
  perf tools: callchain: Fix 'perf report' display to be callchain by default
  perf tools: callchain: Fix spurious 'perf report' warnings: ignore empty callchains
  perf record: Fix the -A UI for empty or non-existent perf.data
  perf util: Fix do_read() to fail on EOF instead of busy-looping
  perf list: Fix the output to not include tracepoints without an id
  perf_counter/powerpc: Fix oops on cpus without perf_counter hardware support
  perf stat: Fix tool option consistency: rename -S/--scale to -c/--scale
  perf report: Add debug help for the finding of symbol bugs - show the symtab origin (DSO, build-id, kernel, etc)
  perf report: Fix per task mult-counter stat reporting
  ...

1 files changed, 13 insertions, 2 deletions

diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h
index 7fb16d90e7b..f64fbaae781 100644
--- a/include/trace/ftrace.h
+++ b/include/trace/ftrace.h
@@ -637,12 +637,20 @@ __attribute__((section("_ftrace_events"))) event_##call = {		\
  *	pc = preempt_count();
  *
  *	__data_size = ftrace_get_offsets_<call>(&__data_offsets, args);
- *	__entry_size = __data_size + sizeof(*entry);
+ *
+ *	// Below we want to get the aligned size by taking into account
+ *	// the u32 field that will later store the buffer size
+ *	__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),
+ *			     sizeof(u64));
+ *	__entry_size -= sizeof(u32);
  *
  *	do {
  *		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);
@@ -685,12 +693,15 @@ static void ftrace_profile_##call(proto)				\
 	pc = preempt_count();						\
 									\
 	__data_size = ftrace_get_offsets_##call(&__data_offsets, args); \
-	__entry_size = ALIGN(__data_size + sizeof(*entry), sizeof(u64));\
+	__entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32),\
+			     sizeof(u64));				\
+	__entry_size -= sizeof(u32);					\
 									\
 	do {								\
 		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);	\