Commit d4b9e425 authored by Tobin C. Harding's avatar Tobin C. Harding Committed by Rob Herring
Browse files

of: unittest: Remove VLA stack usage 

The kernel would like to have all stack VLA usage removed[1].  This is a
test function so the execution speed is not critical.  We can allocate
memory for this buffer instead of using a VLA.  If kmalloc() fails just
return.

Allocate buffer with kmalloc().

[1]: https://lkml.org/lkml/2018/3/7/621



Signed-off-by: default avatarTobin C. Harding <me@tobin.cc>
Signed-off-by: default avatarRob Herring <robh@kernel.org>
parent a514266b

drivers/of/unittest.c

+11 −4
Original line number Diff line number Diff line
@@ -254,12 +254,18 @@ static void __init of_unittest_check_tree_linkage(void) 
static void __init of_unittest_printf_one(struct device_node *np, const char *fmt,

					  const char *expected)

{

	unsigned char buf[strlen(expected)+10];

	unsigned char *buf;

	int buf_size;

	int size, i;



	buf_size = strlen(expected) + 10;

	buf = kmalloc(buf_size, GFP_KERNEL);

	if (!buf)

		return;



	/* Baseline; check conversion with a large size limit */

	memset(buf, 0xff, sizeof(buf));

	size = snprintf(buf, sizeof(buf) - 2, fmt, np);

	memset(buf, 0xff, buf_size);

	size = snprintf(buf, buf_size - 2, fmt, np);



	/* use strcmp() instead of strncmp() here to be absolutely sure strings match */

	unittest((strcmp(buf, expected) == 0) && (buf[size+1] == 0xff),
@@ -270,12 +276,13 @@ static void __init of_unittest_printf_one(struct device_node *np, const char *fm 
	size++;

	for (i = 0; i < 2; i++, size--) {

		/* Clear the buffer, and make sure it works correctly still */

		memset(buf, 0xff, sizeof(buf));

		memset(buf, 0xff, buf_size);

		snprintf(buf, size+1, fmt, np);

		unittest(strncmp(buf, expected, size) == 0 && (buf[size+1] == 0xff),

			"snprintf failed; size=%i fmt='%s' expected='%s' rslt='%s'\n",

			size, fmt, expected, buf);

	}

	kfree(buf);

}



static void __init of_unittest_printf(void)

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