From fd0e6852c407dd9aefc594f54ddcc21d84803d3b Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Wed, 5 Feb 2020 11:27:02 +0530 Subject: [PATCH] tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu Fix following instances of sparse error kernel/trace/ftrace.c:5667:29: error: incompatible types in comparison kernel/trace/ftrace.c:5813:21: error: incompatible types in comparison kernel/trace/ftrace.c:5868:36: error: incompatible types in comparison kernel/trace/ftrace.c:5870:25: error: incompatible types in comparison Use rcu_dereference_protected to dereference the newly annotated pointer. Link: http://lkml.kernel.org/r/20200205055701.30195-1-frextrite@gmail.com Signed-off-by: Amol Grover Signed-off-by: Steven Rostedt (VMware) --- kernel/trace/ftrace.c | 2 +- kernel/trace/trace.h | 8 ++++++-- 2 files changed, 7 insertions(+), 3 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 01d2ecd..481ede3 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5592,7 +5592,7 @@ static const struct file_operations ftrace_notrace_fops = { static DEFINE_MUTEX(graph_lock); struct ftrace_hash __rcu *ftrace_graph_hash = EMPTY_HASH; -struct ftrace_hash *ftrace_graph_notrace_hash = EMPTY_HASH; +struct ftrace_hash __rcu *ftrace_graph_notrace_hash = EMPTY_HASH; enum graph_filter_type { GRAPH_FILTER_NOTRACE = 0, diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 18ceab5..022def9 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -965,7 +965,7 @@ extern void __trace_graph_return(struct trace_array *tr, #ifdef CONFIG_DYNAMIC_FTRACE extern struct ftrace_hash __rcu *ftrace_graph_hash; -extern struct ftrace_hash *ftrace_graph_notrace_hash; +extern struct ftrace_hash __rcu *ftrace_graph_notrace_hash; static inline int ftrace_graph_addr(struct ftrace_graph_ent *trace) { @@ -1018,10 +1018,14 @@ static inline void ftrace_graph_addr_finish(struct ftrace_graph_ret *trace) static inline int ftrace_graph_notrace_addr(unsigned long addr) { int ret = 0; + struct ftrace_hash *notrace_hash; preempt_disable_notrace(); - if (ftrace_lookup_ip(ftrace_graph_notrace_hash, addr)) + notrace_hash = rcu_dereference_protected(ftrace_graph_notrace_hash, + !preemptible()); + + if (ftrace_lookup_ip(notrace_hash, addr)) ret = 1; preempt_enable_notrace(); -- 2.7.4