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authorAmol Grover <frextrite@gmail.com>2020-02-01 12:57:04 +0530
committerSteven Rostedt (VMware) <rostedt@goodmis.org>2020-02-05 17:14:26 -0500
commit24a9729f831462b1d9d61dc85ecc91c59037243f (patch)
tree5dba5453c90b039bac3afe99f4d2d25fd6f4200a /kernel
parent7495e0926fdf302cb9e62a49f7c22198815624cd (diff)
downloadlinux-24a9729f831462b1d9d61dc85ecc91c59037243f.tar.bz2
tracing: Annotate ftrace_graph_hash pointer with __rcu
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. Link: http://lkml.kernel.org/r/20200201072703.17330-1-frextrite@gmail.com Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org> Signed-off-by: Amol Grover <frextrite@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/ftrace.c2
-rw-r--r--kernel/trace/trace.h9
2 files changed, 7 insertions, 4 deletions
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 0e9612c30995..01d2ecd66161 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -5591,7 +5591,7 @@ 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 f5480a2aa334..18ceab59a5ba 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -964,22 +964,25 @@ 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