[GIT PULL][v3.6] tracing: Check for allocation failure in __tracing_open()

[Steven Rostedt <rostedt@goodmis.org>]

Ingo,

Dan found a bug that is in the queue for 3.6. Please add this for the
3.6 queue.

Thanks,

Steve

Please pull the latest tip/perf/core tree, which can be found at:

  git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace.git
tip/perf/core

Head SHA1: 93574fcc5b50cc7b8834698acb2ce947e5b6a5dc


Dan Carpenter (1):
      tracing: Check for allocation failure in __tracing_open()

----
 kernel/trace/trace.c |    4 ++++
 1 file changed, 4 insertions(+)
---------------------------
commit 93574fcc5b50cc7b8834698acb2ce947e5b6a5dc
Author: Dan Carpenter <dan.carpenter@oracle.com>
Date:   Wed Jul 11 09:35:08 2012 +0300

    tracing: Check for allocation failure in __tracing_open()
    
    Clean up and return -ENOMEM on if the kzalloc() fails.
    
    This also prevents a potential crash, as the pointer that failed to
    allocate would be later used.
    
    Link: http://lkml.kernel.org/r/20120711063507.GF11812@elgon.mountain
    
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: Ingo Molnar <mingo@redhat.com>
    Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
    Signed-off-by: Steven Rostedt <rostedt@goodmis.org>

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 814ff30..a120f98 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -2390,6 +2390,9 @@ __tracing_open(struct inode *inode, struct file *file)
 
 	iter->buffer_iter = kzalloc(sizeof(*iter->buffer_iter) * num_possible_cpus(),
 				    GFP_KERNEL);
+	if (!iter->buffer_iter)
+		goto release;
+
 	/*
 	 * We make a copy of the current tracer to avoid concurrent
 	 * changes on it while we are reading.
@@ -2451,6 +2454,7 @@ __tracing_open(struct inode *inode, struct file *file)
 	mutex_unlock(&trace_types_lock);
 	kfree(iter->trace);
 	kfree(iter->buffer_iter);
+release:
 	seq_release_private(inode, file);
 	return ERR_PTR(-ENOMEM);
 }