trace_events_hist: add check for return value of 'create_hist_field'

stable inclusion
from stable-v5.10.166
commit 886aa449235f478e262bbd5dcdee6ed6bc202949
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7TH9O

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=886aa449235f478e262bbd5dcdee6ed6bc202949

--------------------------------

commit 8b152e91 upstream.

Function 'create_hist_field' is called recursively at
trace_events_hist.c:1954 and can return NULL-value that's why we have
to check it to avoid null pointer dereference.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Link: https://lkml.kernel.org/r/20230111120409.4111-1-n.petrova@fintech.ru

Cc: stable@vger.kernel.org
Fixes: 30350d65 ("tracing: Add variable support to hist triggers")
Signed-off-by: NNatalia Petrova <n.petrova@fintech.ru>
Signed-off-by: NSteven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Nsanglipeng <sanglipeng1@jd.com>

kernel/trace/trace_events_hist.c

@@ -1646,6 +1646,8 @@ static struct hist_field *create_hist_field(struct hist_trigger_data *hist_data,
 		unsigned long fl = flags & ~HIST_FIELD_FL_LOG2;
 		hist_field->fn = hist_field_log2;
 		hist_field->operands[0] = create_hist_field(hist_data, field, fl, NULL);
+		if (!hist_field->operands[0])
+			goto free;
 		hist_field->size = hist_field->operands[0]->size;
 		hist_field->type = kstrdup(hist_field->operands[0]->type, GFP_KERNEL);
 		if (!hist_field->type)