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Date: Fri, 18 Oct 2013 17:59:42 -0300 From: "Geyslan G. Bem" <geyslan@...il.com> To: kernel-br@...glegroups.com Cc: "Geyslan G. Bem" <geyslan@...il.com>, Steven Rostedt <rostedt@...dmis.org>, Frederic Weisbecker <fweisbec@...il.com>, Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org (open list) Subject: [PATCH 2/2] tracing: fix referencing after memory freeing and refactors code In 'system_tr_open()': Fix possible 'dir' assignment after freeing it. In both functions: Restructures logic conditions testing 'tracing_is_disabled()' return before the others tests. Centralizes the exiting in accordance to Coding Style, Chapter 7. Signed-off-by: Geyslan G. Bem <geyslan@...il.com> --- kernel/trace/trace_events.c | 46 +++++++++++++++++++++++---------------------- 1 file changed, 24 insertions(+), 22 deletions(-) diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index 368a4d5..0f56ebf 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1060,7 +1060,10 @@ static int subsystem_open(struct inode *inode, struct file *filp) struct event_subsystem *system = NULL; struct ftrace_subsystem_dir *dir = NULL; /* Initialize for gcc */ struct trace_array *tr; - int ret; + int ret = -ENODEV; + + if (tracing_is_disabled()) + return ret; /* Make sure the system still exists */ mutex_lock(&trace_types_lock); @@ -1082,23 +1085,21 @@ static int subsystem_open(struct inode *inode, struct file *filp) mutex_unlock(&trace_types_lock); if (!system) - return -ENODEV; + return ret; /* Some versions of gcc think dir can be uninitialized here */ WARN_ON(!dir); /* Still need to increment the ref count of the system */ - if (trace_array_get(tr) < 0) { - put_system(dir); - return -ENODEV; - } + ret = trace_array_get(tr); + if (ret) + goto err_get; - ret = tracing_open_generic(inode, filp); - if (ret < 0) { - trace_array_put(tr); - put_system(dir); - } + filp->private_data = dir; + return 0; +err_get: + put_system(dir); return ret; } @@ -1106,28 +1107,29 @@ static int system_tr_open(struct inode *inode, struct file *filp) { struct ftrace_subsystem_dir *dir; struct trace_array *tr = inode->i_private; - int ret; + int ret = -ENODEV; - if (trace_array_get(tr) < 0) - return -ENODEV; + if (tracing_is_disabled()) + return ret; + + ret = trace_array_get(tr); + if (ret) + return ret; /* Make a temporary dir that has no system but points to tr */ dir = kzalloc(sizeof(*dir), GFP_KERNEL); if (!dir) { - trace_array_put(tr); - return -ENOMEM; + ret = -ENOMEM; + goto err_dir; } dir->tr = tr; - ret = tracing_open_generic(inode, filp); - if (ret < 0) { - trace_array_put(tr); - kfree(dir); - } - filp->private_data = dir; + return 0; +err_dir: + trace_array_put(tr); return ret; } -- 1.8.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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