This patch set proposes KUnit, a lightweight unit testing and mocking
framework for the Linux kernel.
Unlike Autotest and kselftest, KUnit is a true unit testing framework;
it does not require installing the kernel on a test machine or in a VM
and does not require tests to be written in userspace running on a host
kernel. Additionally, KUnit is fast: From invocation to completion KUnit
can run several dozen tests in under a second. Currently, the entire
KUnit test suite for KUnit runs in under a second from the initial
invocation (build time excluded).
KUnit is heavily inspired by JUnit, Python's unittest.mock, and
Googletest/Googlemock for C++. KUnit provides facilities for defining
unit test cases, grouping related test cases into test suites, providing
common infrastructure for running tests, mocking, spying, and much more.
## What's so special about unit testing?
A unit test is supposed to test a single unit of code in isolation,
hence the name. There should be no dependencies outside the control of
the test; this means no external dependencies, which makes tests orders
of magnitudes faster. Likewise, since there are no external dependencies,
there are no hoops to jump through to run the tests. Additionally, this
makes unit tests deterministic: a failing unit test always indicates a
problem. Finally, because unit tests necessarily have finer granularity,
they are able to test all code paths easily solving the classic problem
of difficulty in exercising error handling code.
## Is KUnit trying to replace other testing frameworks for the kernel?
No. Most existing tests for the Linux kernel are end-to-end tests, which
have their place. A well tested system has lots of unit tests, a
reasonable number of integration tests, and some end-to-end tests. KUnit
is just trying to address the unit test space which is currently not
being addressed.
## More information on KUnit
There is a bunch of documentation near the end of this patch set that
describes how to use KUnit and best practices for writing unit tests.
For convenience I am hosting the compiled docs here:
https://google.github.io/kunit-docs/third_party/kernel/docs/
--
2.19.1.331.ge82ca0e54c-goog
If test is being directly executed (with stdout opened on the
terminal) and the terminal capabilities indicate enough
colors, then use the existing scheme of green, red, and blue
to show when tests pass, fail or end in a different way.
When running the tests redirecting the stdout, for instance,
to a file, then colors are not shown, thus producing a more
readable output.
Signed-off-by: Daniel Díaz <daniel.diaz(a)linaro.org>
---
tools/testing/selftests/ftrace/ftracetest | 29 +++++++++++++++++------
1 file changed, 22 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/ftrace/ftracetest b/tools/testing/selftests/ftrace/ftracetest
index 4946b2edfcff..d987bbec675f 100755
--- a/tools/testing/selftests/ftrace/ftracetest
+++ b/tools/testing/selftests/ftrace/ftracetest
@@ -152,6 +152,21 @@ else
date > $LOG_FILE
fi
+# Define text colors
+# Check available colors on the terminal, if any
+ncolors=`tput colors 2>/dev/null`
+color_reset=
+color_red=
+color_green=
+color_blue=
+# If stdout exists and number of colors is eight or more, use them
+if [ -t 1 -a "$ncolors" -a "$ncolors" -ge 8 ]; then
+ color_reset="\e[0m"
+ color_red="\e[31m"
+ color_green="\e[32m"
+ color_blue="\e[34m"
+fi
+
prlog() { # messages
[ -z "$LOG_FILE" ] && echo -e "$@" || echo -e "$@" | tee -a $LOG_FILE
}
@@ -195,37 +210,37 @@ test_on_instance() { # testfile
eval_result() { # sigval
case $1 in
$PASS)
- prlog " [\e[32mPASS\e[30m]"
+ prlog " [${color_green}PASS${color_reset}]"
PASSED_CASES="$PASSED_CASES $CASENO"
return 0
;;
$FAIL)
- prlog " [\e[31mFAIL\e[30m]"
+ prlog " [${color_red}FAIL${color_reset}]"
FAILED_CASES="$FAILED_CASES $CASENO"
return 1 # this is a bug.
;;
$UNRESOLVED)
- prlog " [\e[34mUNRESOLVED\e[30m]"
+ prlog " [${color_blue}UNRESOLVED${color_reset}]"
UNRESOLVED_CASES="$UNRESOLVED_CASES $CASENO"
return 1 # this is a kind of bug.. something happened.
;;
$UNTESTED)
- prlog " [\e[34mUNTESTED\e[30m]"
+ prlog " [${color_blue}UNTESTED${color_reset}]"
UNTESTED_CASES="$UNTESTED_CASES $CASENO"
return 0
;;
$UNSUPPORTED)
- prlog " [\e[34mUNSUPPORTED\e[30m]"
+ prlog " [${color_blue}UNSUPPORTED${color_reset}]"
UNSUPPORTED_CASES="$UNSUPPORTED_CASES $CASENO"
return $UNSUPPORTED_RESULT # depends on use case
;;
$XFAIL)
- prlog " [\e[31mXFAIL\e[30m]"
+ prlog " [${color_red}XFAIL${color_reset}]"
XFAILED_CASES="$XFAILED_CASES $CASENO"
return 0
;;
*)
- prlog " [\e[34mUNDEFINED\e[30m]"
+ prlog " [${color_blue}UNDEFINED${color_reset}]"
UNDEFINED_CASES="$UNDEFINED_CASES $CASENO"
return 1 # this must be a test bug
;;
--
2.17.1
Android uses ashmem for sharing memory regions. We are looking forward
to migrating all usecases of ashmem to memfd so that we can possibly
remove the ashmem driver in the future from staging while also
benefiting from using memfd and contributing to it. Note staging drivers
are also not ABI and generally can be removed at anytime.
One of the main usecases Android has is the ability to create a region
and mmap it as writeable, then drop its protection for "future" writes
while keeping the existing already mmap'ed writeable-region active.
This allows us to implement a usecase where receivers of the shared
memory buffer can get a read-only view, while the sender continues to
write to the buffer. See CursorWindow in Android for more details:
https://developer.android.com/reference/android/database/CursorWindow
This usecase cannot be implemented with the existing F_SEAL_WRITE seal.
To support the usecase, this patch adds a new F_SEAL_FS_WRITE seal which
prevents any future mmap and write syscalls from succeeding while
keeping the existing mmap active. The following program shows the seal
working in action:
int main() {
int ret, fd;
void *addr, *addr2, *addr3, *addr1;
ret = memfd_create_region("test_region", REGION_SIZE);
printf("ret=%d\n", ret);
fd = ret;
// Create map
addr = mmap(0, REGION_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (addr == MAP_FAILED)
printf("map 0 failed\n");
else
printf("map 0 passed\n");
if ((ret = write(fd, "test", 4)) != 4)
printf("write failed even though no fs-write seal "
"(ret=%d errno =%d)\n", ret, errno);
else
printf("write passed\n");
addr1 = mmap(0, REGION_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (addr1 == MAP_FAILED)
perror("map 1 prot-write failed even though no seal\n");
else
printf("map 1 prot-write passed as expected\n");
ret = fcntl(fd, F_ADD_SEALS, F_SEAL_FS_WRITE);
if (ret == -1)
printf("fcntl failed, errno: %d\n", errno);
else
printf("fs-write seal now active\n");
if ((ret = write(fd, "test", 4)) != 4)
printf("write failed as expected due to fs-write seal\n");
else
printf("write passed (unexpected)\n");
addr2 = mmap(0, REGION_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
if (addr2 == MAP_FAILED)
perror("map 2 prot-write failed as expected due to seal\n");
else
printf("map 2 passed\n");
addr3 = mmap(0, REGION_SIZE, PROT_READ, MAP_SHARED, fd, 0);
if (addr3 == MAP_FAILED)
perror("map 3 failed\n");
else
printf("map 3 prot-read passed as expected\n");
}
The output of running this program is as follows:
ret=3
map 0 passed
write passed
map 1 prot-write passed as expected
fs-write seal now active
write failed as expected due to fs-write seal
map 2 prot-write failed as expected due to seal
: Permission denied
map 3 prot-read passed as expected
Note: This seal will also prevent growing and shrinking of the memfd.
This is not something we do in Android so it does not affect us, however
I have mentioned this behavior of the seal in the manpage.
Cc: jreck(a)google.com
Cc: john.stultz(a)linaro.org
Cc: tkjos(a)google.com
Cc: gregkh(a)linuxfoundation.org
Signed-off-by: Joel Fernandes (Google) <joel(a)joelfernandes.org>
---
v1->v2: No change, just added selftests to the series. manpages are
ready and I'll submit them once the patches are accepted.
include/uapi/linux/fcntl.h | 1 +
mm/memfd.c | 6 +++++-
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/fcntl.h b/include/uapi/linux/fcntl.h
index c98312fa78a5..fe44a2035edf 100644
--- a/include/uapi/linux/fcntl.h
+++ b/include/uapi/linux/fcntl.h
@@ -41,6 +41,7 @@
#define F_SEAL_SHRINK 0x0002 /* prevent file from shrinking */
#define F_SEAL_GROW 0x0004 /* prevent file from growing */
#define F_SEAL_WRITE 0x0008 /* prevent writes */
+#define F_SEAL_FS_WRITE 0x0010 /* prevent all write-related syscalls */
/* (1U << 31) is reserved for signed error codes */
/*
diff --git a/mm/memfd.c b/mm/memfd.c
index 27069518e3c5..9b8855b80de9 100644
--- a/mm/memfd.c
+++ b/mm/memfd.c
@@ -150,7 +150,8 @@ static unsigned int *memfd_file_seals_ptr(struct file *file)
#define F_ALL_SEALS (F_SEAL_SEAL | \
F_SEAL_SHRINK | \
F_SEAL_GROW | \
- F_SEAL_WRITE)
+ F_SEAL_WRITE | \
+ F_SEAL_FS_WRITE)
static int memfd_add_seals(struct file *file, unsigned int seals)
{
@@ -219,6 +220,9 @@ static int memfd_add_seals(struct file *file, unsigned int seals)
}
}
+ if ((seals & F_SEAL_FS_WRITE) && !(*file_seals & F_SEAL_FS_WRITE))
+ file->f_mode &= ~(FMODE_WRITE | FMODE_PWRITE);
+
*file_seals |= seals;
error = 0;
--
2.19.0.605.g01d371f741-goog
Makefile contains -D_GNU_SOURCE. remove define "_GNU_SOURCE"
in c files.
Signed-off-by: Peng Hao <peng.hao2(a)zte.com.cn>
---
tools/testing/selftests/proc/fd-001-lookup.c | 2 +-
tools/testing/selftests/proc/fd-003-kthread.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/proc/fd-001-lookup.c b/tools/testing/selftests/proc/fd-001-lookup.c
index a2010df..60d7948 100644
--- a/tools/testing/selftests/proc/fd-001-lookup.c
+++ b/tools/testing/selftests/proc/fd-001-lookup.c
@@ -14,7 +14,7 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
// Test /proc/*/fd lookup.
-#define _GNU_SOURCE
+
#undef NDEBUG
#include <assert.h>
#include <dirent.h>
diff --git a/tools/testing/selftests/proc/fd-003-kthread.c b/tools/testing/selftests/proc/fd-003-kthread.c
index 1d659d5..dc591f9 100644
--- a/tools/testing/selftests/proc/fd-003-kthread.c
+++ b/tools/testing/selftests/proc/fd-003-kthread.c
@@ -14,7 +14,7 @@
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
// Test that /proc/$KERNEL_THREAD/fd/ is empty.
-#define _GNU_SOURCE
+
#undef NDEBUG
#include <sys/syscall.h>
#include <assert.h>
--
1.8.3.1
Fixes the following warnings:
dirty_log_test.c: In function ‘help’:
dirty_log_test.c:216:9: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 2 has type ‘int’ [-Wformat=]
printf(" -i: specify iteration counts (default: %"PRIu64")\n",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from include/test_util.h:18:0,
from dirty_log_test.c:16:
/usr/include/inttypes.h:105:34: note: format string is defined here
# define PRIu64 __PRI64_PREFIX "u"
dirty_log_test.c:218:9: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 2 has type ‘int’ [-Wformat=]
printf(" -I: specify interval in ms (default: %"PRIu64" ms)\n",
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from include/test_util.h:18:0,
from dirty_log_test.c:16:
/usr/include/inttypes.h:105:34: note: format string is defined here
# define PRIu64 __PRI64_PREFIX "u"
Signed-off-by: Andrea Parri <andrea.parri(a)amarulasolutions.com>
---
tools/testing/selftests/kvm/dirty_log_test.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/kvm/dirty_log_test.c b/tools/testing/selftests/kvm/dirty_log_test.c
index 0c2cdc105f968..a9c4b5e21d7e7 100644
--- a/tools/testing/selftests/kvm/dirty_log_test.c
+++ b/tools/testing/selftests/kvm/dirty_log_test.c
@@ -31,9 +31,9 @@
/* How many pages to dirty for each guest loop */
#define TEST_PAGES_PER_LOOP 1024
/* How many host loops to run (one KVM_GET_DIRTY_LOG for each loop) */
-#define TEST_HOST_LOOP_N 32
+#define TEST_HOST_LOOP_N 32UL
/* Interval for each host loop (ms) */
-#define TEST_HOST_LOOP_INTERVAL 10
+#define TEST_HOST_LOOP_INTERVAL 10UL
/*
* Guest variables. We use these variables to share data between host
--
2.17.1
Hello Jay Kamat,
This is a semi-automatic email about new static checker warnings.
The patch 48c2bb0b9cf8: "Fix cg_read_strcmp()" from Sep 7, 2018,
leads to the following Smatch complaint:
./tools/testing/selftests/cgroup/cgroup_util.c:111 cg_read_strcmp()
error: we previously assumed 'expected' could be null (see line 97)
./tools/testing/selftests/cgroup/cgroup_util.c
96 /* Handle the case of comparing against empty string */
97 if (!expected)
^^^^^^^^
Originally, we assumed that expected was non-NULL but we added a check
here. I feel like maybe the intention was to check was supposed to be:
if (expected[0] == '\0')
but that's just a random guess.
98 size = 32;
99 else
100 size = strlen(expected) + 1;
101
102 buf = malloc(size);
103 if (!buf)
104 return -1;
105
106 if (cg_read(cgroup, control, buf, size)) {
107 free(buf);
108 return -1;
109 }
110
111 ret = strcmp(expected, buf);
^^^^^^^^
Unchecked dereference.
112 free(buf);
113 return ret;
regards,
dan carpenter