Currently this tests tries to umount /sys/kernel/debug (TDIR) but the
system it is running on may have mounts below.
For example, danobi/vmtest [0] VMs have
mount -t tracefs tracefs /sys/kernel/debug/tracing
as part of their init.
This change instead creates a "random" directory under /tmp and uses this
as TDIR.
If the directory already exists, ignore the error and keep moving on.
Test:
Originally:
$ vmtest -k $KERNEL_REPO/arch/x86_64/boot/bzImage "./test_progs -vv -a test_bpffs"
=> bzImage
===> Booting
===> Setting up VM
===> Running command
[ 2.138818] bpf_testmod: loading out-of-tree module taints kernel.
[ 2.140913] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_test_bpffs:PASS:clone 0 nsec
fn:PASS:unshare 0 nsec
fn:PASS:mount / 0 nsec
fn:FAIL:umount /sys/kernel/debug unexpected error: -1 (errno 16)
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_test_bpffs:PASS:clone 0 nsec
test_test_bpffs:PASS:waitpid 0 nsec
test_test_bpffs:FAIL:bpffs test failed 255#282 test_bpffs:FAIL
Summary: 0/0 PASSED, 0 SKIPPED, 1 FAILED
Successfully unloaded bpf_testmod.ko.
Command failed with exit code: 1
After this change:
$ vmtest -k $(make image_name) 'cd tools/testing/selftests/bpf && ./test_progs -vv -a test_bpffs'
=> bzImage
===> Booting
===> Setting up VM
===> Running command
[ 2.295696] bpf_testmod: loading out-of-tree module taints kernel.
[ 2.296468] bpf_testmod: module verification failed: signature and/or required key missing - tainting kernel
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_test_bpffs:PASS:clone 0 nsec
fn:PASS:unshare 0 nsec
fn:PASS:mount / 0 nsec
fn:PASS:mount tmpfs 0 nsec
fn:PASS:mkdir /tmp/test_bpffs_testdir/fs1 0 nsec
fn:PASS:mkdir /tmp/test_bpffs_testdir/fs2 0 nsec
fn:PASS:mount bpffs /tmp/test_bpffs_testdir/fs1 0 nsec
fn:PASS:mount bpffs /tmp/test_bpffs_testdir/fs2 0 nsec
fn:PASS:reading /tmp/test_bpffs_testdir/fs1/maps.debug 0 nsec
fn:PASS:reading /tmp/test_bpffs_testdir/fs2/progs.debug 0 nsec
fn:PASS:creating /tmp/test_bpffs_testdir/fs1/a 0 nsec
fn:PASS:creating /tmp/test_bpffs_testdir/fs1/a/1 0 nsec
fn:PASS:creating /tmp/test_bpffs_testdir/fs1/b 0 nsec
fn:PASS:create_map(ARRAY) 0 nsec
fn:PASS:pin map 0 nsec
fn:PASS:stat(/tmp/test_bpffs_testdir/fs1/a) 0 nsec
fn:PASS:renameat2(/fs1/a, /fs1/b, RENAME_EXCHANGE) 0 nsec
fn:PASS:stat(/tmp/test_bpffs_testdir/fs1/b) 0 nsec
fn:PASS:b should have a's inode 0 nsec
fn:PASS:access(/tmp/test_bpffs_testdir/fs1/b/1) 0 nsec
fn:PASS:stat(/tmp/test_bpffs_testdir/fs1/map) 0 nsec
fn:PASS:renameat2(/fs1/c, /fs1/b, RENAME_EXCHANGE) 0 nsec
fn:PASS:stat(/tmp/test_bpffs_testdir/fs1/b) 0 nsec
fn:PASS:b should have c's inode 0 nsec
fn:PASS:access(/tmp/test_bpffs_testdir/fs1/c/1) 0 nsec
fn:PASS:renameat2(RENAME_NOREPLACE) 0 nsec
fn:PASS:access(/tmp/test_bpffs_testdir/fs1/b) 0 nsec
bpf_testmod.ko is already unloaded.
Loading bpf_testmod.ko...
Successfully loaded bpf_testmod.ko.
test_test_bpffs:PASS:clone 0 nsec
test_test_bpffs:PASS:waitpid 0 nsec
test_test_bpffs:PASS:bpffs test 0 nsec
#282 test_bpffs:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Successfully unloaded bpf_testmod.ko.
[0] https://github.com/danobi/vmtest
This is a follow-up of https://lore.kernel.org/bpf/20231024201852.1512720-1-chantr4@xxxxxxxxx/T/
v1 -> v2:
- use a TDIR name that is related to test
- use C-style comments
Signed-off-by: Manu Bretelle <chantr4@xxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/test_bpffs.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
index 214d9f4a94a5..ea933fd151c3 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c
@@ -8,7 +8,8 @@
#include <sys/types.h>
#include <test_progs.h>
-#define TDIR "/sys/kernel/debug"
+/* TDIR must be in a location we can create a directory in. */
+#define TDIR "/tmp/test_bpffs_testdir"
static int read_iter(char *file)
{
@@ -43,8 +44,11 @@ static int fn(void)
if (!ASSERT_OK(err, "mount /"))
goto out;
- err = umount(TDIR);
- if (!ASSERT_OK(err, "umount " TDIR))
+ err = mkdir(TDIR, 0777);
+ /* If the directory already exists we can carry on. It may be left over
+ * from a previous run.
+ */
+ if ((err && errno != EEXIST) && !ASSERT_OK(err, "mkdir " TDIR))
goto out;
err = mount("none", TDIR, "tmpfs", 0, NULL);
@@ -138,6 +142,7 @@ static int fn(void)
rmdir(TDIR "/fs1");
rmdir(TDIR "/fs2");
umount(TDIR);
+ rmdir(TDIR);
exit(err);
}
--
2.40.1
