On Thu, Oct 26, 2023 at 11:08:35PM -0700, Yonghong Song wrote: > > On 10/24/23 10:41 PM, Manu Bretelle wrote: > > On Tue, Oct 24, 2023 at 02:29:19PM -0700, Kui-Feng Lee wrote: > > > > > > On 10/24/23 13:18, Manu Bretelle wrote: > > > > 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 list mounts and will umount any mounts below TDIR before > > > > umounting TDIR itself. > > > > > > > > Note that it is not umounting recursively, so in the case of a sub-mount > > > > of TDIR having another sub-mount, this will fail as mtab is ordered. > > > Should we move TID to a random path likes "/sys/kernel/debug-<pid>/"? > > > > > Fair point, I suppose we would want to keep TDIR a defined string as it does > > simplify the gymnastic involved through the rest of the script, but yeah > > looking at the original commit: > > edb65ee5aa25 (selftests/bpf: Add bpffs preload test) > > > > I don't see any reason to use an alternate directory and rather mkdir it vs > > umounting the original one. > > so something like > > > > #define TDIR "/sys/kernel/test_bpffs" > > > > Would probably do. > > > > Alexei could confirm his original intent probably. > > > Maybe/sys/kernel/tracing should work too? Not sure whether it is universally > available or not. > > I think we just need an existing directory (whichever) to mount tmpfs on, and Alexei previous comment seems to confirm that. But importantly, nothing that has sub-mounts if we don't want to get into the business of recursively umounting sub-mounts. I will just pick up a name which is random enough to not realistically exist on a system, mkdir it instead of the existing umount(TDIR) and we should be good. > > > > > > 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 > > > > [ 2.035210] bpf_testmod: loading out-of-tree module taints kernel. > > > > [ 2.036510] 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:accessing /etc/mtab 0 nsec > > > > fn:PASS:umount /sys/kernel/debug/tracing 0 nsec > > > > fn:PASS:umount /sys/kernel/debug 0 nsec > > > > fn:PASS:mount tmpfs 0 nsec > > > > fn:PASS:mkdir /sys/kernel/debug/fs1 0 nsec > > > > fn:PASS:mkdir /sys/kernel/debug/fs2 0 nsec > > > > fn:PASS:mount bpffs /sys/kernel/debug/fs1 0 nsec > > > > fn:PASS:mount bpffs /sys/kernel/debug/fs2 0 nsec > > > > fn:PASS:reading /sys/kernel/debug/fs1/maps.debug 0 nsec > > > > fn:PASS:reading /sys/kernel/debug/fs2/progs.debug 0 nsec > > > > fn:PASS:creating /sys/kernel/debug/fs1/a 0 nsec > > > > fn:PASS:creating /sys/kernel/debug/fs1/a/1 0 nsec > > > > fn:PASS:creating /sys/kernel/debug/fs1/b 0 nsec > > > > fn:PASS:create_map(ARRAY) 0 nsec > > > > fn:PASS:pin map 0 nsec > > > > fn:PASS:stat(/sys/kernel/debug/fs1/a) 0 nsec > > > > fn:PASS:renameat2(/fs1/a, /fs1/b, RENAME_EXCHANGE) 0 nsec > > > > fn:PASS:stat(/sys/kernel/debug/fs1/b) 0 nsec > > > > fn:PASS:b should have a's inode 0 nsec > > > > fn:PASS:access(/sys/kernel/debug/fs1/b/1) 0 nsec > > > > fn:PASS:stat(/sys/kernel/debug/fs1/map) 0 nsec > > > > fn:PASS:renameat2(/fs1/c, /fs1/b, RENAME_EXCHANGE) 0 nsec > > > > fn:PASS:stat(/sys/kernel/debug/fs1/b) 0 nsec > > > > fn:PASS:b should have c's inode 0 nsec > > > > fn:PASS:access(/sys/kernel/debug/fs1/c/1) 0 nsec > > > > fn:PASS:renameat2(RENAME_NOREPLACE) 0 nsec > > > > fn:PASS:access(/sys/kernel/debug/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 > > > > > > > > Signed-off-by: Manu Bretelle <chantr4@xxxxxxxxx> > > > > --- > > > > .../selftests/bpf/prog_tests/test_bpffs.c | 28 +++++++++++++++++++ > > > > 1 file changed, 28 insertions(+) > > > > > > > > diff --git a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > > > index 214d9f4a94a5..001bf694c269 100644 > > > > --- a/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > > > +++ b/tools/testing/selftests/bpf/prog_tests/test_bpffs.c > > > > @@ -3,12 +3,14 @@ > > > > #define _GNU_SOURCE > > > > #include <stdio.h> > > > > #include <sched.h> > > > > +#include <mntent.h> > > > > #include <sys/mount.h> > > > > #include <sys/stat.h> > > > > #include <sys/types.h> > > > > #include <test_progs.h> > > > > #define TDIR "/sys/kernel/debug" > > > > +#define MTAB "/etc/mtab" > > > > static int read_iter(char *file) > > > > { > > > > @@ -32,6 +34,8 @@ static int read_iter(char *file) > > > > static int fn(void) > > > > { > > > > + /* A buffer to store logging messages */ > > > > + char buf[1024]; > > > > struct stat a, b, c; > > > > int err, map; > > > > @@ -43,6 +47,30 @@ static int fn(void) > > > > if (!ASSERT_OK(err, "mount /")) > > > > goto out; > > > > + /* TDIR may have mounts below. unount them first */ > > > > + FILE *mtab = setmntent(MTAB, "r"); > > > > + > > > > + if (!ASSERT_TRUE(mtab != NULL, "accessing " MTAB)) { > > > > + err = errno; > > > > + goto out; > > > > + } > > > > + > > > > + struct mntent *mnt = NULL; > > > > + > > > > + while ((mnt = getmntent(mtab)) != NULL) { > > > > + if (strlen(mnt->mnt_dir) > strlen(TDIR) && > > > > + strncmp(TDIR, mnt->mnt_dir, strlen(TDIR)) == 0) { > > > > + snprintf(buf, sizeof(buf) - 1, "umount %s", mnt->mnt_dir); > > > > + err = umount(mnt->mnt_dir); > > > > + if (!ASSERT_OK(err, buf)) { > > > > + endmntent(mtab); > > > > + goto out; > > > > + } > > > > + } > > > > + } > > > > + // Ignore any error here > > > > + endmntent(mtab); > > > > + > > > > err = umount(TDIR); > > > > if (!ASSERT_OK(err, "umount " TDIR)) > > > > goto out;
