From: Amol Grover <frextrite@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>, Ingo Molnar <mingo@redhat.com>
Cc: "Paul E . McKenney" <paulmck@kernel.org>,
linux-kernel@vger.kernel.org,
Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
Joel Fernandes <joel@joelfernandes.org>,
linux-kernel-mentees@lists.linuxfoundation.org
Subject: [Linux-kernel-mentees] [PATCH] tracing: Annotate ftrace_graph_hash pointer with __rcu
Date: Sat, 1 Feb 2020 12:57:04 +0530 [thread overview]
Message-ID: <20200201072703.17330-1-frextrite@gmail.com> (raw)
Fix following instances of sparse error
kernel/trace/ftrace.c:5664:29: error: incompatible types in comparison
kernel/trace/ftrace.c:5785:21: error: incompatible types in comparison
kernel/trace/ftrace.c:5864:36: error: incompatible types in comparison
kernel/trace/ftrace.c:5866:25: error: incompatible types in comparison
Use rcu_dereference_protected to access the __rcu annotated pointer.
Signed-off-by: Amol Grover <frextrite@gmail.com>
---
kernel/trace/ftrace.c | 2 +-
kernel/trace/trace.h | 9 ++++++---
2 files changed, 7 insertions(+), 4 deletions(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 9bf1f2cd515e..959ded08dc13 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5596,7 +5596,7 @@ static const struct file_operations ftrace_notrace_fops = {
static DEFINE_MUTEX(graph_lock);
-struct ftrace_hash *ftrace_graph_hash = EMPTY_HASH;
+struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH;
struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH;
enum graph_filter_type {
diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 63bf60f79398..97dad3326020 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -950,22 +950,25 @@ extern void __trace_graph_return(struct trace_array *tr,
unsigned long flags, int pc);
#ifdef CONFIG_DYNAMIC_FTRACE
-extern struct ftrace_hash *ftrace_graph_hash;
+extern struct ftrace_hash __rcu *ftrace_graph_hash;
extern struct ftrace_hash *ftrace_graph_notrace_hash;
static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace)
{
unsigned long addr = trace->func;
int ret = 0;
+ struct ftrace_hash *hash;
preempt_disable_notrace();
- if (ftrace_hash_empty(ftrace_graph_hash)) {
+ hash = rcu_dereference_protected(ftrace_graph_hash, !preemptible());
+
+ if (ftrace_hash_empty(hash)) {
ret = 1;
goto out;
}
- if (ftrace_lookup_ip(ftrace_graph_hash, addr)) {
+ if (ftrace_lookup_ip(hash, addr)) {
/*
* This needs to be cleared on the return functions
--
2.24.1
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next reply other threads:[~2020-02-01 7:28 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-01 7:27 Amol Grover [this message]
2020-02-03 16:33 ` [Linux-kernel-mentees] [PATCH] tracing: Annotate ftrace_graph_hash pointer with __rcu Joel Fernandes
2020-02-04 10:02 ` Steven Rostedt
2020-02-05 1:01 ` Steven Rostedt
2020-02-05 5:26 ` Amol Grover
2020-02-05 13:11 ` Paul E. McKenney
2020-02-05 13:14 ` Steven Rostedt
2020-02-05 13:19 ` Steven Rostedt
2020-02-05 13:29 ` Paul E. McKenney
2020-02-05 22:06 ` Joel Fernandes
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