From b7d480b827434ce5af4a1037d9b500008502a96d Mon Sep 17 00:00:00 2001 From: Manu Bretelle Date: Fri, 27 Oct 2023 15:30:06 -0700 Subject: [PATCH] selftests/bpf: fix test_bpffs 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 $KERNEL_REPO/arch/x86_64/boot/bzImage "./test_progs -vv -a test_bpffs" => bzImage ===> Booting ===> Setting up VM ===> Running command [ 2.119236] bpf_testmod: loading out-of-tree module taints kernel. [ 2.121768] 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/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1 0 nsec fn:PASS:mkdir /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs2 0 nsec fn:PASS:mount bpffs /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1 0 nsec fn:PASS:mount bpffs /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs2 0 nsec fn:PASS:reading /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/maps.debug 0 nsec fn:PASS:reading /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs2/progs.debug 0 nsec fn:PASS:creating /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/a 0 nsec fn:PASS:creating /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/a/1 0 nsec fn:PASS:creating /tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/b 0 nsec fn:PASS:create_map(ARRAY) 0 nsec fn:PASS:pin map 0 nsec fn:PASS:stat(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/a) 0 nsec fn:PASS:renameat2(/fs1/a, /fs1/b, RENAME_EXCHANGE) 0 nsec fn:PASS:stat(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/b) 0 nsec fn:PASS:b should have a's inode 0 nsec fn:PASS:access(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/b/1) 0 nsec fn:PASS:stat(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/map) 0 nsec fn:PASS:renameat2(/fs1/c, /fs1/b, RENAME_EXCHANGE) 0 nsec fn:PASS:stat(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/b) 0 nsec fn:PASS:b should have c's inode 0 nsec fn:PASS:access(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/fs1/c/1) 0 nsec fn:PASS:renameat2(RENAME_NOREPLACE) 0 nsec fn:PASS:access(/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed/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@gmail.com/T/ Signed-off-by: Manu Bretelle --- tools/testing/selftests/bpf/prog_tests/test_bpffs.c | 10 +++++++--- 1 file changed, 7 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 214d9f4a94a538..80a1afb9589d87 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 #include -#define TDIR "/sys/kernel/debug" +// TDIR must be in a location we can create a directory in. +#define TDIR "/tmp/vvnlhrgunvkrfegnlrvnggcudfgdtrhbfelkebeurfed" static int read_iter(char *file) { @@ -43,8 +44,10 @@ 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 +141,7 @@ static int fn(void) rmdir(TDIR "/fs1"); rmdir(TDIR "/fs2"); umount(TDIR); + rmdir(TDIR); exit(err); }