Commit a870a02c authored Mar 13, 2018 by Arnd Bergmann Committed by David S. Miller Mar 13, 2018

pktgen: use dynamic allocation for debug print buffer



After the removal of the VLA, we get a harmless warning about a large
stack frame:

net/core/pktgen.c: In function 'pktgen_if_write':
net/core/pktgen.c:1710:1: error: the frame size of 1076 bytes is larger than 1024 bytes [-Werror=frame-larger-than=]

The function was previously shown to be safe despite hitting
the 1024 bye warning level. To get rid of the annoyging warning,
while keeping it readable, this changes it to use strndup_user().

Obviously this is not a fast path, so the kmalloc() overhead
can be disregarded.

Fixes: 35951393 ("pktgen: Remove VLA usage")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent be9fc097

net/core/pktgen.c

+8 −7

Original line number	Diff line number	Diff line
		@@ -906,13 +906,14 @@ static ssize_t pktgen_if_write(struct file *file,
		i += len;

		if (debug) {
		size_t copy = min_t(size_t, count, 1023);
		char tb[1024];
		if (copy_from_user(tb, user_buffer, copy))
		return -EFAULT;
		tb[copy] = 0;
		pr_debug("%s,%lu buffer -:%s:-\n",
		name, (unsigned long)count, tb);
		size_t copy = min_t(size_t, count + 1, 1024);
		char *tp = strndup_user(user_buffer, copy);

		if (IS_ERR(tp))
		return PTR_ERR(tp);

		pr_debug("%s,%zu buffer -:%s:-\n", name, count, tp);
		kfree(buf);
		}

		if (!strcmp(name, "min_pkt_size")) {

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