[PATCH v2] fgraph: Fix missing unlock in register_ftrace_graph()
From: Li Huafei <hidden>
Date: 2024-10-24 07:58:33
Also in:
lkml, oe-kbuild
Subsystem:
function hooks (ftrace), the rest, tracing · Maintainers:
Steven Rostedt, Masami Hiramatsu, Linus Torvalds
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 <redacted>
Reported-by: Dan Carpenter <redacted>
Closes: https://lore.kernel.org/r/202410220121.wxg0olfd-lkp@intel.com/ (local)
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Li Huafei <redacted>
---
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