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Message-ID: <20241025101941.516467026@goodmis.org>
Date: Fri, 25 Oct 2024 06:19:11 -0400
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org
Cc: Masami Hiramatsu <mhiramat@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
Andrew Morton <akpm@...ux-foundation.org>,
kernel test robot <lkp@...el.com>,
Dan Carpenter <dan.carpenter@...aro.org>,
Li Huafei <lihuafei1@...wei.com>
Subject: [for-linus][PATCH 1/2] fgraph: Fix missing unlock in register_ftrace_graph()
From: Li Huafei <lihuafei1@...wei.com>
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'.
Link: https://lore.kernel.org/20241024155917.1019580-1-lihuafei1@huawei.com
Fixes: 2c02f7375e65 ("fgraph: Use CPU hotplug mechanism to initialize idle shadow stacks")
Reported-by: kernel test robot <lkp@...el.com>
Reported-by: Dan Carpenter <dan.carpenter@...aro.org>
Closes: https://lore.kernel.org/r/202410220121.wxg0olfd-lkp@intel.com/
Suggested-by: Steven Rostedt <rostedt@...dmis.org>
Signed-off-by: Li Huafei <lihuafei1@...wei.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
---
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;
}
--
2.45.2
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