kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
KUnit tests for initialized data behavior of proc_dointvec that is explicitly checked in the code. Includes basic parsing tests including int min/max overflow. Signed-off-by: Iurii Zaikin <yzaikin@google.com> Signed-off-by: Brendan Higgins <brendanhiggins@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Logan Gunthorpe <logang@deltatee.com> Acked-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Stephen Boyd <sboyd@kernel.org> Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>
This commit is contained in:
Iurii Zaikin
Shuah Khan
parent
804ec79a00
commit
2cb80dbbba
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@ -115,6 +115,8 @@ obj-$(CONFIG_TORTURE_TEST) += torture.o
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obj-$(CONFIG_HAS_IOMEM) += iomem.o
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obj-$(CONFIG_RSEQ) += rseq.o
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obj-$(CONFIG_SYSCTL_KUNIT_TEST) += sysctl-test.o
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obj-$(CONFIG_GCC_PLUGIN_STACKLEAK) += stackleak.o
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KASAN_SANITIZE_stackleak.o := n
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KCOV_INSTRUMENT_stackleak.o := n
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@ -0,0 +1,392 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* KUnit test of proc sysctl.
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*/
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#include <kunit/test.h>
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#include <linux/sysctl.h>
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#define KUNIT_PROC_READ 0
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#define KUNIT_PROC_WRITE 1
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static int i_zero;
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static int i_one_hundred = 100;
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/*
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* Test that proc_dointvec will not try to use a NULL .data field even when the
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* length is non-zero.
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*/
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static void sysctl_test_api_dointvec_null_tbl_data(struct kunit *test)
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{
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struct ctl_table null_data_table = {
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.procname = "foo",
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/*
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* Here we are testing that proc_dointvec behaves correctly when
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* we give it a NULL .data field. Normally this would point to a
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* piece of memory where the value would be stored.
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*/
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.data = NULL,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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/*
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* proc_dointvec expects a buffer in user space, so we allocate one. We
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* also need to cast it to __user so sparse doesn't get mad.
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*/
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void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
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GFP_USER);
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size_t len;
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loff_t pos;
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/*
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* We don't care what the starting length is since proc_dointvec should
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* not try to read because .data is NULL.
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*/
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len = 1234;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
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KUNIT_PROC_READ, buffer, &len,
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&pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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/*
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* See above.
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*/
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len = 1234;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&null_data_table,
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KUNIT_PROC_WRITE, buffer, &len,
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&pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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}
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/*
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* Similar to the previous test, we create a struct ctrl_table that has a .data
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* field that proc_dointvec cannot do anything with; however, this time it is
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* because we tell proc_dointvec that the size is 0.
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*/
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static void sysctl_test_api_dointvec_table_maxlen_unset(struct kunit *test)
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{
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int data = 0;
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struct ctl_table data_maxlen_unset_table = {
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.procname = "foo",
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.data = &data,
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/*
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* So .data is no longer NULL, but we tell proc_dointvec its
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* length is 0, so it still shouldn't try to use it.
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*/
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.maxlen = 0,
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
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GFP_USER);
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size_t len;
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loff_t pos;
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/*
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* As before, we don't care what buffer length is because proc_dointvec
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* cannot do anything because its internal .data buffer has zero length.
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*/
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len = 1234;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
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KUNIT_PROC_READ, buffer, &len,
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&pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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/*
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* See previous comment.
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*/
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len = 1234;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&data_maxlen_unset_table,
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KUNIT_PROC_WRITE, buffer, &len,
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&pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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}
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/*
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* Here we provide a valid struct ctl_table, but we try to read and write from
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* it using a buffer of zero length, so it should still fail in a similar way as
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* before.
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*/
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static void sysctl_test_api_dointvec_table_len_is_zero(struct kunit *test)
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{
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int data = 0;
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/* Good table. */
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
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GFP_USER);
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/*
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* However, now our read/write buffer has zero length.
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*/
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size_t len = 0;
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loff_t pos;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
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&len, &pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE, buffer,
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&len, &pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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}
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/*
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* Test that proc_dointvec refuses to read when the file position is non-zero.
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*/
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static void sysctl_test_api_dointvec_table_read_but_position_set(
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struct kunit *test)
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{
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int data = 0;
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/* Good table. */
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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void __user *buffer = (void __user *)kunit_kzalloc(test, sizeof(int),
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GFP_USER);
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/*
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* We don't care about our buffer length because we start off with a
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* non-zero file position.
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*/
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size_t len = 1234;
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/*
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* proc_dointvec should refuse to read into the buffer since the file
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* pos is non-zero.
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*/
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loff_t pos = 1;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ, buffer,
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&len, &pos));
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KUNIT_EXPECT_EQ(test, (size_t)0, len);
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}
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/*
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* Test that we can read a two digit number in a sufficiently size buffer.
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* Nothing fancy.
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*/
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static void sysctl_test_dointvec_read_happy_single_positive(struct kunit *test)
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{
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int data = 0;
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/* Good table. */
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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size_t len = 4;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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/* Store 13 in the data field. */
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*((int *)table.data) = 13;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
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user_buffer, &len, &pos));
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KUNIT_ASSERT_EQ(test, (size_t)3, len);
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buffer[len] = '\0';
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/* And we read 13 back out. */
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KUNIT_EXPECT_STREQ(test, "13\n", buffer);
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}
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/*
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* Same as previous test, just now with negative numbers.
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*/
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static void sysctl_test_dointvec_read_happy_single_negative(struct kunit *test)
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{
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int data = 0;
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/* Good table. */
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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size_t len = 5;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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*((int *)table.data) = -16;
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_READ,
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user_buffer, &len, &pos));
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KUNIT_ASSERT_EQ(test, (size_t)4, len);
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buffer[len] = '\0';
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KUNIT_EXPECT_STREQ(test, "-16\n", (char *)buffer);
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}
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/*
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* Test that a simple positive write works.
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*/
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static void sysctl_test_dointvec_write_happy_single_positive(struct kunit *test)
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{
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int data = 0;
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/* Good table. */
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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char input[] = "9";
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size_t len = sizeof(input) - 1;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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memcpy(buffer, input, len);
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
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user_buffer, &len, &pos));
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KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
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KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
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KUNIT_EXPECT_EQ(test, 9, *((int *)table.data));
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}
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/*
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* Same as previous test, but now with negative numbers.
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*/
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static void sysctl_test_dointvec_write_happy_single_negative(struct kunit *test)
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{
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int data = 0;
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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char input[] = "-9";
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size_t len = sizeof(input) - 1;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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memcpy(buffer, input, len);
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KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, KUNIT_PROC_WRITE,
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user_buffer, &len, &pos));
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KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
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KUNIT_EXPECT_EQ(test, sizeof(input) - 1, (size_t)pos);
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KUNIT_EXPECT_EQ(test, -9, *((int *)table.data));
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}
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/*
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* Test that writing a value smaller than the minimum possible value is not
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* allowed.
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*/
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static void sysctl_test_api_dointvec_write_single_less_int_min(
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struct kunit *test)
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{
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int data = 0;
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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size_t max_len = 32, len = max_len;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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unsigned long abs_of_less_than_min = (unsigned long)INT_MAX
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- (INT_MAX + INT_MIN) + 1;
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/*
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* We use this rigmarole to create a string that contains a value one
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* less than the minimum accepted value.
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*/
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KUNIT_ASSERT_LT(test,
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(size_t)snprintf(buffer, max_len, "-%lu",
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abs_of_less_than_min),
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max_len);
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KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
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user_buffer, &len, &pos));
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KUNIT_EXPECT_EQ(test, max_len, len);
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KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
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}
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/*
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* Test that writing the maximum possible value works.
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*/
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static void sysctl_test_api_dointvec_write_single_greater_int_max(
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struct kunit *test)
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{
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int data = 0;
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struct ctl_table table = {
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.procname = "foo",
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.data = &data,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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.extra1 = &i_zero,
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.extra2 = &i_one_hundred,
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};
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size_t max_len = 32, len = max_len;
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loff_t pos = 0;
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char *buffer = kunit_kzalloc(test, max_len, GFP_USER);
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char __user *user_buffer = (char __user *)buffer;
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unsigned long greater_than_max = (unsigned long)INT_MAX + 1;
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KUNIT_ASSERT_GT(test, greater_than_max, (unsigned long)INT_MAX);
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KUNIT_ASSERT_LT(test, (size_t)snprintf(buffer, max_len, "%lu",
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greater_than_max),
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max_len);
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KUNIT_EXPECT_EQ(test, -EINVAL, proc_dointvec(&table, KUNIT_PROC_WRITE,
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user_buffer, &len, &pos));
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KUNIT_ASSERT_EQ(test, max_len, len);
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KUNIT_EXPECT_EQ(test, 0, *((int *)table.data));
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}
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static struct kunit_case sysctl_test_cases[] = {
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KUNIT_CASE(sysctl_test_api_dointvec_null_tbl_data),
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KUNIT_CASE(sysctl_test_api_dointvec_table_maxlen_unset),
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KUNIT_CASE(sysctl_test_api_dointvec_table_len_is_zero),
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KUNIT_CASE(sysctl_test_api_dointvec_table_read_but_position_set),
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KUNIT_CASE(sysctl_test_dointvec_read_happy_single_positive),
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KUNIT_CASE(sysctl_test_dointvec_read_happy_single_negative),
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KUNIT_CASE(sysctl_test_dointvec_write_happy_single_positive),
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KUNIT_CASE(sysctl_test_dointvec_write_happy_single_negative),
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KUNIT_CASE(sysctl_test_api_dointvec_write_single_less_int_min),
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KUNIT_CASE(sysctl_test_api_dointvec_write_single_greater_int_max),
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{}
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};
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static struct kunit_suite sysctl_test_suite = {
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.name = "sysctl_test",
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.test_cases = sysctl_test_cases,
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};
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kunit_test_suite(sysctl_test_suite);
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@ -1950,6 +1950,17 @@ config TEST_SYSCTL
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If unsure, say N.
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config SYSCTL_KUNIT_TEST
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bool "KUnit test for sysctl"
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depends on KUNIT
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help
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This builds the proc sysctl unit test, which runs on boot.
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Tests the API contract and implementation correctness of sysctl.
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For more information on KUnit and unit tests in general please refer
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to the KUnit documentation in Documentation/dev-tools/kunit/.
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If unsure, say N.
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config TEST_UDELAY
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tristate "udelay test driver"
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help
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