When running the pidfd_fdinfo_test on arm64, it fails for me. After some
digging, the reason is that the child exits due to SIGBUS, because it
overflows the 1024 byte stack we've reserved for it.
To fix the issue, increase the stack size to 8192 bytes (this number is
somewhat arbitrary, and was arrived at through experimentation -- I kept
doubling until the failure no longer occurred).
Also, let's make the issue easier to debug. wait_for_pid() returns an
ambiguous value: it may return -1 in all of these cases:
1. waitpid() itself returned -1
2. waitpid() returned success, but we found !WIFEXITED(status).
3. The child process exited, but it did so with a -1 exit code.
There's no way for the caller to tell the difference. So, at least log
which occurred, so the test runner can debug things.
While debugging this, I found that we had !WIFEXITED(), because the
child exited due to a signal. This seems like a reasonably common case,
so also print out whether or not we have WIFSIGNALED(), and the
associated WTERMSIG() (if any). This lets us see the SIGBUS I'm fixing
clearly when it occurs.
Finally, I'm suspicious of allocating the child's stack on our stack.
man clone(2) suggests that the correct way to do this is with mmap(),
and in particular by setting MAP_STACK. So, switch to doing it that way
instead.
Signed-off-by: Axel Rasmussen <axelrasmussen(a)google.com>
---
tools/testing/selftests/pidfd/pidfd.h | 13 ++++++++---
.../selftests/pidfd/pidfd_fdinfo_test.c | 22 +++++++++++++++----
2 files changed, 28 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/pidfd/pidfd.h b/tools/testing/selftests/pidfd/pidfd.h
index 01f8d3c0cf2c..6922d6417e1c 100644
--- a/tools/testing/selftests/pidfd/pidfd.h
+++ b/tools/testing/selftests/pidfd/pidfd.h
@@ -68,7 +68,7 @@
#define PIDFD_SKIP 3
#define PIDFD_XFAIL 4
-int wait_for_pid(pid_t pid)
+static inline int wait_for_pid(pid_t pid)
{
int status, ret;
@@ -78,13 +78,20 @@ int wait_for_pid(pid_t pid)
if (errno == EINTR)
goto again;
+ ksft_print_msg("waitpid returned -1, errno=%d\n", errno);
return -1;
}
- if (!WIFEXITED(status))
+ if (!WIFEXITED(status)) {
+ ksft_print_msg(
+ "waitpid !WIFEXITED, WIFSIGNALED=%d, WTERMSIG=%d\n",
+ WIFSIGNALED(status), WTERMSIG(status));
return -1;
+ }
- return WEXITSTATUS(status);
+ ret = WEXITSTATUS(status);
+ ksft_print_msg("waitpid WEXITSTATUS=%d\n", ret);
+ return ret;
}
static inline int sys_pidfd_open(pid_t pid, unsigned int flags)
diff --git a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
index 22558524f71c..3fd8e903118f 100644
--- a/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
+++ b/tools/testing/selftests/pidfd/pidfd_fdinfo_test.c
@@ -12,6 +12,7 @@
#include <string.h>
#include <syscall.h>
#include <sys/wait.h>
+#include <sys/mman.h>
#include "pidfd.h"
#include "../kselftest.h"
@@ -80,7 +81,10 @@ static inline int error_check(struct error *err, const char *test_name)
return err->code;
}
+#define CHILD_STACK_SIZE 8192
+
struct child {
+ char *stack;
pid_t pid;
int fd;
};
@@ -89,17 +93,22 @@ static struct child clone_newns(int (*fn)(void *), void *args,
struct error *err)
{
static int flags = CLONE_PIDFD | CLONE_NEWPID | CLONE_NEWNS | SIGCHLD;
- size_t stack_size = 1024;
- char *stack[1024] = { 0 };
struct child ret;
if (!(flags & CLONE_NEWUSER) && geteuid() != 0)
flags |= CLONE_NEWUSER;
+ ret.stack = mmap(NULL, CHILD_STACK_SIZE, PROT_READ | PROT_WRITE,
+ MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
+ if (ret.stack == MAP_FAILED) {
+ error_set(err, -1, "mmap of stack failed (errno %d)", errno);
+ return ret;
+ }
+
#ifdef __ia64__
- ret.pid = __clone2(fn, stack, stack_size, flags, args, &ret.fd);
+ ret.pid = __clone2(fn, ret.stack, CHILD_STACK_SIZE, flags, args, &ret.fd);
#else
- ret.pid = clone(fn, stack + stack_size, flags, args, &ret.fd);
+ ret.pid = clone(fn, ret.stack + CHILD_STACK_SIZE, flags, args, &ret.fd);
#endif
if (ret.pid < 0) {
@@ -129,6 +138,11 @@ static inline int child_join(struct child *child, struct error *err)
else if (r > 0)
error_set(err, r, "child %d reported: %d", child->pid, r);
+ if (munmap(child->stack, CHILD_STACK_SIZE)) {
+ error_set(err, -1, "munmap of child stack failed (errno %d)", errno);
+ r = -1;
+ }
+
return r;
}
--
2.35.0.rc2.247.g8bbb082509-goog
The first half of these patch set improves the code logic and has no
user visible effect. The second half improves the script output, to
make it clearer and nicer to read.
Guillaume Nault (4):
selftests: fib rule: Make 'getmatch' and 'match' local variables
selftests: fib rule: Drop erroneous TABLE variable
selftests: fib rule: Log test description
selftests: fib rule: Don't echo modified sysctls
tools/testing/selftests/net/fib_rule_tests.sh | 26 ++++++++++++-------
1 file changed, 17 insertions(+), 9 deletions(-)
--
2.21.3
Update the document to clarifiy support for running mainline
kselftest on stable releases and the reasons for not removing
test code that can test older kernels.
Signed-off-by: Shuah Khan <skhan(a)linuxfoundation.org>
---
Documentation/dev-tools/kselftest.rst | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/Documentation/dev-tools/kselftest.rst b/Documentation/dev-tools/kselftest.rst
index dcefee707ccd..a833ecf12fbc 100644
--- a/Documentation/dev-tools/kselftest.rst
+++ b/Documentation/dev-tools/kselftest.rst
@@ -7,6 +7,14 @@ directory. These are intended to be small tests to exercise individual code
paths in the kernel. Tests are intended to be run after building, installing
and booting a kernel.
+Kselftest from mainline can be run on older stable kernels. Running tests
+from mainline offers the best coverage. Several test rings run mainline
+kselftest suite on stable releases. The reason is that when a new test
+gets added to test existing code to regression test a bug, we should be
+able to run that test on an older kernel. Hence, it is important to keep
+code that can still test an older kernel and make sure it skips the test
+gracefully on newer releases.
+
You can find additional information on Kselftest framework, how to
write new tests using the framework on Kselftest wiki:
--
2.32.0
Since v1 [1], I added Quentin's acks and applied Andrii's suggestions:
* Pass CFLAGS to libbpf link in patch 3
* Substitute CLANG_CROSS_FLAGS whole in HOST_CFLAGS to avoid accidents,
patch 4
Add support for cross-building BPF tools and selftests with clang, by
passing LLVM=1 or CC=clang to make, as well as CROSS_COMPILE. A single
clang toolchain can generate binaries for multiple architectures, so
instead of having prefixes such as aarch64-linux-gnu-gcc, clang uses the
-target parameter: `clang -target aarch64-linux-gnu'.
Patch 1 adds the parameter in Makefile.include so tools can easily
support this. Patch 2 prepares for the libbpf change from patch 3 (keep
building resolve_btfids's libbpf in the host arch, when cross-building
the kernel with clang). Patches 3-6 enable cross-building BPF tools with
clang.
[1] https://lore.kernel.org/bpf/20211122192019.1277299-1-jean-philippe@linaro.o…
Jean-Philippe Brucker (6):
tools: Help cross-building with clang
tools/resolve_btfids: Support cross-building the kernel with clang
tools/libbpf: Enable cross-building with clang
bpftool: Enable cross-building with clang
tools/runqslower: Enable cross-building with clang
selftests/bpf: Enable cross-building with clang
tools/bpf/bpftool/Makefile | 13 +++++++------
tools/bpf/resolve_btfids/Makefile | 1 +
tools/bpf/runqslower/Makefile | 4 ++--
tools/lib/bpf/Makefile | 3 ++-
tools/scripts/Makefile.include | 13 ++++++++++++-
tools/testing/selftests/bpf/Makefile | 8 ++++----
6 files changed, 28 insertions(+), 14 deletions(-)
--
2.34.1
Allow the ageing timeout that is set on bridges to be customized from
forwarding.config. This allows the tests to be run on hardware which
does not support a 10s timeout (e.g. mv88e6xxx).
Signed-off-by: Tobias Waldekranz <tobias(a)waldekranz.com>
---
tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh | 5 +++--
.../testing/selftests/net/forwarding/bridge_vlan_unaware.sh | 5 +++--
.../selftests/net/forwarding/forwarding.config.sample | 2 ++
tools/testing/selftests/net/forwarding/lib.sh | 1 +
4 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh b/tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh
index b90dff8d3a94..64bd00fe9a4f 100755
--- a/tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh
+++ b/tools/testing/selftests/net/forwarding/bridge_vlan_aware.sh
@@ -28,8 +28,9 @@ h2_destroy()
switch_create()
{
- # 10 Seconds ageing time.
- ip link add dev br0 type bridge vlan_filtering 1 ageing_time 1000 \
+ ip link add dev br0 type bridge \
+ vlan_filtering 1 \
+ ageing_time $LOW_AGEING_TIME \
mcast_snooping 0
ip link set dev $swp1 master br0
diff --git a/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh b/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh
index c15c6c85c984..1c8a26046589 100755
--- a/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh
+++ b/tools/testing/selftests/net/forwarding/bridge_vlan_unaware.sh
@@ -27,8 +27,9 @@ h2_destroy()
switch_create()
{
- # 10 Seconds ageing time.
- ip link add dev br0 type bridge ageing_time 1000 mcast_snooping 0
+ ip link add dev br0 type bridge \
+ ageing_time $LOW_AGEING_TIME \
+ mcast_snooping 0
ip link set dev $swp1 master br0
ip link set dev $swp2 master br0
diff --git a/tools/testing/selftests/net/forwarding/forwarding.config.sample b/tools/testing/selftests/net/forwarding/forwarding.config.sample
index b0980a2efa31..4a546509de90 100644
--- a/tools/testing/selftests/net/forwarding/forwarding.config.sample
+++ b/tools/testing/selftests/net/forwarding/forwarding.config.sample
@@ -41,6 +41,8 @@ NETIF_CREATE=yes
# Timeout (in seconds) before ping exits regardless of how many packets have
# been sent or received
PING_TIMEOUT=5
+# Minimum ageing_time (in centiseconds) supported by hardware
+LOW_AGEING_TIME=1000
# Flag for tc match, supposed to be skip_sw/skip_hw which means do not process
# filter by software/hardware
TC_FLAG=skip_hw
diff --git a/tools/testing/selftests/net/forwarding/lib.sh b/tools/testing/selftests/net/forwarding/lib.sh
index 7da783d6f453..e7e434a4758b 100644
--- a/tools/testing/selftests/net/forwarding/lib.sh
+++ b/tools/testing/selftests/net/forwarding/lib.sh
@@ -24,6 +24,7 @@ PING_COUNT=${PING_COUNT:=10}
PING_TIMEOUT=${PING_TIMEOUT:=5}
WAIT_TIMEOUT=${WAIT_TIMEOUT:=20}
INTERFACE_TIMEOUT=${INTERFACE_TIMEOUT:=600}
+LOW_AGEING_TIME=${LOW_AGEING_TIME:=1000}
REQUIRE_JQ=${REQUIRE_JQ:=yes}
REQUIRE_MZ=${REQUIRE_MZ:=yes}
--
2.25.1