| From 02e5db5f218b39e76233b8e5cba88eb912d20d6a Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Sat, 1 Feb 2020 12:57:04 +0530 |
| Subject: tracing: Annotate ftrace_graph_hash pointer with __rcu |
| |
| From: Amol Grover <frextrite@gmail.com> |
| |
| [ Upstream commit 24a9729f831462b1d9d61dc85ecc91c59037243f ] |
| |
| 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> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| 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 37a435bac1618..00d987d9bd4a6 100644 |
| --- a/kernel/trace/ftrace.c |
| +++ b/kernel/trace/ftrace.c |
| @@ -5072,7 +5072,7 @@ 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 d11d7bfc3fa5c..70806f2f89bab 100644 |
| --- a/kernel/trace/trace.h |
| +++ b/kernel/trace/trace.h |
| @@ -872,22 +872,25 @@ 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 |
| -- |
| 2.20.1 |
| |