Use guard(mutex)() to acquire and automatically release ftrace_lock,
fixing the issue of not unlocking when calling cpuhp_setup_state()
fails.
Fixes smatch warning:
kernel/trace/fgraph.c:1317 register_ftrace_graph() warn: inconsistent returns
'&ftrace_lock'.
Fixes: 2c02f7375e65 ("fgraph: Use CPU hotplug mechanism to initialize idle
shadow stacks")
Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Closes: https://lore.kernel.org/r/[email protected]/
Suggested-by: Steven Rostedt <[email protected]>
Signed-off-by: Li Huafei <[email protected]>
---
Changes in v2:
- Use guard() to acquire and automatically release ftrace_lock.
---
kernel/trace/fgraph.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/kernel/trace/fgraph.c b/kernel/trace/fgraph.c
index 41e7a15dcb50..cd1c2946018c 100644
--- a/kernel/trace/fgraph.c
+++ b/kernel/trace/fgraph.c
@@ -1252,7 +1252,7 @@ int register_ftrace_graph(struct fgraph_ops *gops)
int ret = 0;
int i = -1;
- mutex_lock(&ftrace_lock);
+ guard(mutex)(&ftrace_lock);
if (!fgraph_initialized) {
ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "fgraph_idle_init",
@@ -1273,10 +1273,8 @@ int register_ftrace_graph(struct fgraph_ops *gops)
}
i = fgraph_lru_alloc_index();
- if (i < 0 || WARN_ON_ONCE(fgraph_array[i] != &fgraph_stub)) {
- ret = -ENOSPC;
- goto out;
- }
+ if (i < 0 || WARN_ON_ONCE(fgraph_array[i] != &fgraph_stub))
+ return -ENOSPC;
gops->idx = i;
ftrace_graph_active++;
@@ -1313,8 +1311,6 @@ int register_ftrace_graph(struct fgraph_ops *gops)
gops->saved_func = NULL;
fgraph_lru_release_index(i);
}
-out:
- mutex_unlock(&ftrace_lock);
return ret;
}
--
2.25.1
