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tracing: Fix some alloc_event_probe() error handling bugs

PATCH New Dan Carpenter 1 participant 1 message Aug 24, 2021

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Kernel janitors Tracing
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Dan Carpenter

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PATCH 1/1 tracing: Fix some alloc_event_probe() error handling bugs

There are two bugs in this code. First, if the kzalloc() fails it leads to a NULL dereference of "ep" on the next line. Second, if the alloc_event_probe() function retursn an error then it leads to an error pointer dereference in the caller.

Fixes 7491e2c44278 ("tracing: Add a probe that attaches to trace events")
Signed-off-by Dan Carpenter <[email protected]>
---
 kernel/trace/trace_eprobe.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
kernel/trace/trace_eprobe.c +3 -2
index 56a96e9750cf..3044b762cbd7 100644
@@ -151,7 +151,7 @@ static struct trace_eprobe *alloc_event_probe(const char *group,
 
 	ep = kzalloc(struct_size(ep, tp.args, nargs), GFP_KERNEL);
 	if (!ep) {
-		trace_event_put_ref(ep->event);
+		trace_event_put_ref(event);
 		goto error;
 	}
 	ep->event = event;

@@ -851,7 +851,8 @@ static int __trace_eprobe_create(int argc, const char *argv[])
 		ret = PTR_ERR(ep);
 		/* This must return -ENOMEM, else there is a bug */
 		WARN_ON_ONCE(ret != -ENOMEM);
-		goto error;	/* We know ep is not allocated */
+		ep = NULL;
+		goto error;
 	}
 
 	argc -= 2; argv += 2;
Signature · 1 line
2.20.1