Commit b4a00288 authored by SeongJae Park's avatar SeongJae Park Committed by Linus Torvalds
Browse files

selftests/damon: test debugfs file reads/writes with huge count 

DAMON debugfs interface users were able to trigger warning by writing
some files with arbitrarily large 'count' parameter.  The issue is fixed
with commit db7a347b ("mm/damon/dbgfs: use '__GFP_NOWARN' for
user-specified size buffer allocation").  This commit adds a test case
for the issue in DAMON selftests to avoid future regressions.

Link: https://lkml.kernel.org/r/20211201150440.1088-11-sj@kernel.org


Signed-off-by: default avatarSeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d85570c6

tools/testing/selftests/damon/.gitignore

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# SPDX-License-Identifier: GPL-2.0-only

huge_count_read_write

tools/testing/selftests/damon/Makefile

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# SPDX-License-Identifier: GPL-2.0

# Makefile for damon selftests



TEST_GEN_FILES += huge_count_read_write



TEST_FILES = _chk_dependency.sh

TEST_PROGS = debugfs_attrs.sh

tools/testing/selftests/damon/debugfs_attrs.sh

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@@ -105,4 +105,22 @@ orig_monitor_on=$(cat "$DBGFS/monitor_on") 
test_write_fail "$DBGFS/monitor_on" "on" "orig_monitor_on" "empty target ids"

echo "$orig_target_ids" > "$DBGFS/target_ids"



# Test huge count read write

# ==========================



dmesg -C



for file in "$DBGFS/"*

do

	./huge_count_read_write "$file"

done



if dmesg | grep -q WARNING

then

	dmesg

	exit 1

else

	exit 0

fi



echo "PASS"

tools/testing/selftests/damon/huge_count_read_write.c

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// SPDX-License-Identifier: GPL-2.0

/*

 * Author: SeongJae Park <sj@kernel.org>

 */



#include <fcntl.h>

#include <stdlib.h>

#include <unistd.h>

#include <stdio.h>



void write_read_with_huge_count(char *file)

{

	int filedesc = open(file, O_RDWR);

	char buf[25];

	int ret;



	printf("%s %s\n", __func__, file);

	if (filedesc < 0) {

		fprintf(stderr, "failed opening %s\n", file);

		exit(1);

	}



	write(filedesc, "", 0xfffffffful);

	perror("after write: ");

	ret = read(filedesc, buf, 0xfffffffful);

	perror("after read: ");

	close(filedesc);

}



int main(int argc, char *argv[])

{

	if (argc != 2) {

		fprintf(stderr, "Usage: %s <file>\n", argv[0]);

		exit(1);

	}

	write_read_with_huge_count(argv[1]);



	return 0;

}