On Mon, Feb 10, 2020 at 4:40 AM Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > From: Amol Grover <frextrite@xxxxxxxxx> > > [ Upstream commit 24a9729f831462b1d9d61dc85ecc91c59037243f ] Amol, can you send a follow-up patch to annotate ftrace_graph_notrace_hash as well? - Joel > > 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@xxxxxxxxx > > Reviewed-by: Joel Fernandes (Google) <joel@xxxxxxxxxxxxxxxxx> > Signed-off-by: Amol Grover <frextrite@xxxxxxxxx> > Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > --- > 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 9bf1f2cd515ef..959ded08dc13f 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 63bf60f793987..97dad33260208 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 > -- > 2.20.1 > > >
