[Dle-develop] [PATCH tracing/kprobes 5/6] tracing/kprobes: Fix profiling alignment for perf_counter buffer

[Masami H. <mhi...@re...>]

Fix *probe_profile_func() to align buffer size, since pref_counter requires.

Signed-off-by: Masami Hiramatsu <mhi...@re...>
Cc: Jim Keniston <jke...@us...>
Cc: Ananth N Mavinakayanahalli <an...@in...>
Cc: Andi Kleen <ak...@li...>
Cc: Christoph Hellwig <hc...@in...>
Cc: Frank Ch. Eigler <fc...@re...>
Cc: Frederic Weisbecker <fwe...@gm...>
Cc: H. Peter Anvin <hp...@zy...>
Cc: Ingo Molnar <mi...@el...>
Cc: Jason Baron <jb...@re...>
Cc: K.Prasad <pr...@li...>
Cc: Lai Jiangshan <la...@cn...>
Cc: Li Zefan <li...@cn...>
Cc: Peter Zijlstra <pe...@in...>
Cc: Srikar Dronamraju <sr...@li...>
Cc: Steven Rostedt <ro...@go...>
Cc: Tom Zanussi <tza...@gm...>
---

 kernel/trace/trace_kprobe.c |   17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 70b632c..d8db935 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -1149,18 +1149,23 @@ static __kprobes int kprobe_profile_func(struct kprobe *kp,
 	struct trace_probe *tp = container_of(kp, struct trace_probe, rp.kp);
 	struct ftrace_event_call *call = &tp->call;
 	struct kprobe_trace_entry *entry;
-	int size, i, pc;
+	int size, __size, i, pc;
 	unsigned long irq_flags;
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
-	size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+	__size = SIZEOF_KPROBE_TRACE_ENTRY(tp->nr_args);
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
 
 	do {
 		char raw_data[size];
 		struct trace_entry *ent;
-
+		/*
+		 * Zero dead bytes from alignment to avoid stack leak
+		 * to userspace
+		 */
 		*(u64 *)(&raw_data[size - sizeof(u64)]) = 0ULL;
 		entry = (struct kprobe_trace_entry *)raw_data;
 		ent = &entry->ent;
@@ -1183,13 +1188,15 @@ static __kprobes int kretprobe_profile_func(struct kretprobe_instance *ri,
 	struct trace_probe *tp = container_of(ri->rp, struct trace_probe, rp);
 	struct ftrace_event_call *call = &tp->call;
 	struct kretprobe_trace_entry *entry;
-	int size, i, pc;
+	int size, __size, i, pc;
 	unsigned long irq_flags;
 
 	local_save_flags(irq_flags);
 	pc = preempt_count();
 
-	size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+	__size = SIZEOF_KRETPROBE_TRACE_ENTRY(tp->nr_args);
+	size = ALIGN(__size + sizeof(u32), sizeof(u64));
+	size -= sizeof(u32);
 
 	do {
 		char raw_data[size];


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhi...@re...