[PATCH 5.2 076/143] ftrace: Check for successful allocation of hash

From: Greg Kroah-Hartman
Date: Wed Sep 04 2019 - 14:12:21 EST


From: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>

commit 5b0022dd32b7c2e15edf1827ba80aa1407edf9ff upstream.

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.rao@xxxxxxxxxxxxxxxxxx

Cc: stable@xxxxxxxxxxxxxxx
Fixes: 1ec3a81a0cf42 ("ftrace: Have each function probe use its own ftrace_ops")
Signed-off-by: Naveen N. Rao <naveen.n.rao@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
kernel/trace/ftrace.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -4330,6 +4330,11 @@ register_ftrace_function_probe(char *glo
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? */