Linux-Fsdevel Archive on lore.kernel.org
 help / color / Atom feed
From: Brendan Higgins <brendanhiggins@google.com>
To: Stephen Boyd <sboyd@kernel.org>
Cc: Iurii Zaikin <yzaikin@google.com>,
	frowand.list@gmail.com, gregkh@linuxfoundation.org,
	jpoimboe@redhat.com, keescook@google.com,
	kieran.bingham@ideasonboard.com, mcgrof@kernel.org,
	peterz@infradead.org, robh@kernel.org, shuah@kernel.org,
	tytso@mit.edu, yamada.masahiro@socionext.com,
	devicetree@vger.kernel.org, dri-devel@lists.freedesktop.org,
	kunit-dev@googlegroups.com, linux-doc@vger.kernel.org,
	linux-fsdevel@vger.kernel.org, linux-kbuild@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-nvdimm@lists.01.org, linux-um@lists.infradead.org,
	Alexander.Levin@microsoft.com, Tim.Bird@sony.com,
	amir73il@gmail.com, dan.carpenter@oracle.com, daniel@ffwll.ch,
	jdike@addtoit.com, joel@jms.id.au, julia.lawall@lip6.fr,
	khilman@baylibre.com, knut.omang@oracle.com, logang@deltatee.com,
	mpe@ellerman.id.au, pmladek@suse.com, rdunlap@infradead.org,
	richard@nod.at, rientjes@google.com, rostedt@goodmis.org,
	wfg@linux.intel.com
Subject: Re: [PATCH v4 17/18] kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec()
Date: Tue, 11 Jun 2019 10:58:30 -0700
Message-ID: <20190611175830.GA236872@google.com> (raw)
In-Reply-To: <20190607190047.C3E7A20868@mail.kernel.org>

On Fri, Jun 07, 2019 at 12:00:47PM -0700, Stephen Boyd wrote:
> Quoting Iurii Zaikin (2019-06-05 18:29:42)
> > On Fri, May 17, 2019 at 11:22 AM Stephen Boyd <sboyd@kernel.org> wrote:
> > >
> > > Quoting Brendan Higgins (2019-05-14 15:17:10)
> > > > diff --git a/kernel/sysctl-test.c b/kernel/sysctl-test.c
> > > > new file mode 100644
> > > > index 0000000000000..fe0f2bae66085
> > > > --- /dev/null
> > > > +++ b/kernel/sysctl-test.c
> > > > +
> > > > +
> > > > +static void sysctl_test_dointvec_happy_single_negative(struct kunit *test)
> > > > +{
> > > > +       struct ctl_table table = {
> > > > +               .procname = "foo",
> > > > +               .data           = &test_data.int_0001,
> > > > +               .maxlen         = sizeof(int),
> > > > +               .mode           = 0644,
> > > > +               .proc_handler   = proc_dointvec,
> > > > +               .extra1         = &i_zero,
> > > > +               .extra2         = &i_one_hundred,
> > > > +       };
> > > > +       char input[] = "-9";
> > > > +       size_t len = sizeof(input) - 1;
> > > > +       loff_t pos = 0;
> > > > +
> > > > +       table.data = kunit_kzalloc(test, sizeof(int), GFP_USER);
> > > > +       KUNIT_EXPECT_EQ(test, 0, proc_dointvec(&table, 1, input, &len, &pos));
> > > > +       KUNIT_EXPECT_EQ(test, sizeof(input) - 1, len);
> > > > +       KUNIT_EXPECT_EQ(test, sizeof(input) - 1, pos);
> > > > +       KUNIT_EXPECT_EQ(test, -9, *(int *)table.data);
> > >
> > > Is the casting necessary? Or can the macro do a type coercion of the
> > > second parameter based on the first type?
> >  Data field is defined as void* so I believe casting is necessary to
> > dereference it as a pointer to an array of ints. I don't think the
> > macro should do any type coercion that == operator wouldn't do.
> >  I did change the cast to make it more clear that it's a pointer to an
> > array of ints being dereferenced.
> 
> Ok, I still wonder if we should make KUNIT_EXPECT_EQ check the types on
> both sides and cause a build warning/error if the types aren't the same.
> This would be similar to our min/max macros that complain about
> mismatched types in the comparisons. Then if a test developer needs to
> convert one type or the other they could do so with a
> KUNIT_EXPECT_EQ_T() macro that lists the types to coerce both sides to
> explicitly.

Do you think it would be better to do a phony compare similar to how
min/max used to work prior to 4.17, or to use the new __typecheck(...)
macro? This might seem like a dumb question (and maybe it is), but Iurii
and I thought the former created an error message that was a bit easier
to understand, whereas __typecheck is obviously superior in terms of
code reuse.

This is what we are thinking right now; if you don't have any complaints
I will squash it into the relevant commits on the next revision:
---
From: Iurii Zaikin <yzaikin@google.com>

Adds a warning message when comparing values of different types similar
to what min() / max() macros do.

Signed-off-by: Iurii Zaikin <yzaikin@google.com>
---
 include/kunit/test.h | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/include/kunit/test.h b/include/kunit/test.h
index 511c9e85401a6..791e22fba5620 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -335,6 +335,13 @@ void __printf(3, 4) kunit_printk(const char *level,
 #define kunit_err(test, fmt, ...) \
 		kunit_printk(KERN_ERR, test, fmt, ##__VA_ARGS__)
 
+/*
+ * 'Unnecessary' cast serves to generate a compile-time warning in case
+ * of comparing incompatible types. Inspired by include/linux/kernel.h
+ */
+#define __kunit_typecheck(lhs, rhs) \
+	((void) (&(lhs) == &(rhs)))
+
 static inline struct kunit_stream *kunit_expect_start(struct kunit *test,
 						      const char *file,
 						      const char *line)
@@ -514,6 +521,7 @@ static inline void kunit_expect_ptr_binary(struct kunit *test,
 #define KUNIT_EXPECT_BINARY(test, left, condition, right) do {		       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_expect_binary(test,					       \
 			    (long long) __left, #left,			       \
 			    (long long) __right, #right,		       \
@@ -524,6 +532,7 @@ static inline void kunit_expect_ptr_binary(struct kunit *test,
 #define KUNIT_EXPECT_BINARY_MSG(test, left, condition, right, fmt, ...) do {   \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_expect_binary_msg(test,					       \
 				(long long) __left, #left,		       \
 				(long long) __right, #right,		       \
@@ -538,6 +547,7 @@ static inline void kunit_expect_ptr_binary(struct kunit *test,
 #define KUNIT_EXPECT_PTR_BINARY(test, left, condition, right) do {	       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_expect_ptr_binary(test,					       \
 			    (void *) __left, #left,			       \
 			    (void *) __right, #right,			       \
@@ -553,6 +563,7 @@ static inline void kunit_expect_ptr_binary(struct kunit *test,
 				    ...) do {				       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_expect_ptr_binary_msg(test,				       \
 				    (void *) __left, #left,		       \
 				    (void *) __right, #right,		       \
@@ -1013,6 +1024,7 @@ static inline void kunit_assert_ptr_binary(struct kunit *test,
 #define KUNIT_ASSERT_BINARY(test, left, condition, right) do {		       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_assert_binary(test,					       \
 			    (long long) __left, #left,			       \
 			    (long long) __right, #right,		       \
@@ -1023,6 +1035,7 @@ static inline void kunit_assert_ptr_binary(struct kunit *test,
 #define KUNIT_ASSERT_BINARY_MSG(test, left, condition, right, fmt, ...) do {   \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_assert_binary_msg(test,					       \
 				(long long) __left, #left,		       \
 				(long long) __right, #right,		       \
@@ -1037,6 +1050,7 @@ static inline void kunit_assert_ptr_binary(struct kunit *test,
 #define KUNIT_ASSERT_PTR_BINARY(test, left, condition, right) do {	       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_assert_ptr_binary(test,					       \
 				(void *) __left, #left,			       \
 				(void *) __right, #right,		       \
@@ -1051,6 +1065,7 @@ static inline void kunit_assert_ptr_binary(struct kunit *test,
 				    fmt, ...) do {			       \
 	typeof(left) __left = (left);					       \
 	typeof(right) __right = (right);				       \
+	__kunit_typecheck(__left, __right);				       \
 	kunit_assert_ptr_binary_msg(test,				       \
 				    (void *) __left, #left,		       \
 				    (void *) __right, #right,		       \
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


  parent reply index

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-14 22:16 [PATCH v4 00/18] kunit: introduce KUnit, the Linux kernel unit testing framework Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 01/18] kunit: test: add KUnit test runner core Brendan Higgins
2019-05-17  0:35   ` Stephen Boyd
2019-05-17 18:53   ` Stephen Boyd
2019-06-14 23:22     ` Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 02/18] kunit: test: add test resource management API Brendan Higgins
2019-05-17  0:38   ` Stephen Boyd
2019-06-04 23:34     ` Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 03/18] kunit: test: add string_stream a std::stream like string builder Brendan Higgins
2019-05-17 17:42   ` Stephen Boyd
2019-06-05  0:19     ` Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 04/18] kunit: test: add kunit_stream a std::stream like logger Brendan Higgins
2019-05-17 17:58   ` Stephen Boyd
2019-06-05  0:47     ` Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 05/18] kunit: test: add the concept of expectations Brendan Higgins
2019-05-14 22:16 ` [PATCH v4 06/18] kbuild: enable building KUnit Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 07/18] kunit: test: add initial tests Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 08/18] objtool: add kunit_try_catch_throw to the noreturn list Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 09/18] kunit: test: add support for test abort Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 10/18] kunit: test: add tests for kunit " Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 11/18] kunit: test: add the concept of assertions Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 12/18] kunit: test: add tests for KUnit managed resources Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 13/18] kunit: tool: add Python wrappers for running KUnit tests Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 14/18] kunit: defconfig: add defconfigs for building " Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 15/18] Documentation: kunit: add documentation for KUnit Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 16/18] MAINTAINERS: add entry for KUnit the unit testing framework Brendan Higgins
2019-05-14 23:25   ` Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 17/18] kernel/sysctl-test: Add null pointer test for sysctl.c:proc_dointvec() Brendan Higgins
2019-05-17 18:22   ` Stephen Boyd
2019-06-06  1:29     ` Iurii Zaikin
2019-06-07 19:00       ` Stephen Boyd
2019-06-07 22:22         ` Brendan Higgins
2019-06-11 17:58         ` Brendan Higgins [this message]
2019-06-11 18:50           ` Stephen Boyd
2019-06-11 20:29             ` Brendan Higgins
2019-05-14 22:17 ` [PATCH v4 18/18] MAINTAINERS: add proc sysctl KUnit test to PROC SYSCTL section Brendan Higgins

Reply instructions:

You may reply publically to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20190611175830.GA236872@google.com \
    --to=brendanhiggins@google.com \
    --cc=Alexander.Levin@microsoft.com \
    --cc=Tim.Bird@sony.com \
    --cc=amir73il@gmail.com \
    --cc=dan.carpenter@oracle.com \
    --cc=daniel@ffwll.ch \
    --cc=devicetree@vger.kernel.org \
    --cc=dri-devel@lists.freedesktop.org \
    --cc=frowand.list@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jdike@addtoit.com \
    --cc=joel@jms.id.au \
    --cc=jpoimboe@redhat.com \
    --cc=julia.lawall@lip6.fr \
    --cc=keescook@google.com \
    --cc=khilman@baylibre.com \
    --cc=kieran.bingham@ideasonboard.com \
    --cc=knut.omang@oracle.com \
    --cc=kunit-dev@googlegroups.com \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kbuild@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-nvdimm@lists.01.org \
    --cc=linux-um@lists.infradead.org \
    --cc=logang@deltatee.com \
    --cc=mcgrof@kernel.org \
    --cc=mpe@ellerman.id.au \
    --cc=peterz@infradead.org \
    --cc=pmladek@suse.com \
    --cc=rdunlap@infradead.org \
    --cc=richard@nod.at \
    --cc=rientjes@google.com \
    --cc=robh@kernel.org \
    --cc=rostedt@goodmis.org \
    --cc=sboyd@kernel.org \
    --cc=shuah@kernel.org \
    --cc=tytso@mit.edu \
    --cc=wfg@linux.intel.com \
    --cc=yamada.masahiro@socionext.com \
    --cc=yzaikin@google.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

Linux-Fsdevel Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-fsdevel/0 linux-fsdevel/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-fsdevel linux-fsdevel/ https://lore.kernel.org/linux-fsdevel \
		linux-fsdevel@vger.kernel.org linux-fsdevel@archiver.kernel.org
	public-inbox-index linux-fsdevel


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-fsdevel


AGPL code for this site: git clone https://public-inbox.org/ public-inbox