From: "Naveen N. Rao" <[email protected]>

In register_ftrace_function_probe(), we are not checking the return
value of alloc_and_copy_ftrace_hash(). The subsequent call to
ftrace_match_records() may end up dereferencing the same. Add a check to
ensure this doesn't happen.

Link: 
http://lkml.kernel.org/r/26e92574f25ad23e7cafa3cf5f7a819de1832cbe.1562249521.git.naveen.n....@linux.vnet.ibm.com

Cc: [email protected]
Fixes: 1ec3a81a0cf42 ("ftrace: Have each function probe use its own ftrace_ops")
Signed-off-by: Naveen N. Rao <[email protected]>
Signed-off-by: Steven Rostedt (VMware) <[email protected]>
---
 kernel/trace/ftrace.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 6200a6fe10e3..f9821a3374e9 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4338,6 +4338,11 @@ register_ftrace_function_probe(char *glob, struct 
trace_array *tr,
        old_hash = *orig_hash;
        hash = alloc_and_copy_ftrace_hash(FTRACE_HASH_DEFAULT_BITS, old_hash);
 
+       if (!hash) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
        ret = ftrace_match_records(hash, glob, strlen(glob));
 
        /* Nothing found? */
-- 
2.20.1


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