From 24a9729f831462b1d9d61dc85ecc91c59037243f Mon Sep 17 00:00:00 2001 From: Amol Grover Date: Sat, 1 Feb 2020 12:57:04 +0530 Subject: [PATCH] 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) Signed-off-by: Amol Grover Signed-off-by: Steven Rostedt (VMware) --- 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 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 -- GitLab