diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c index 1748dff58c3b..cfc614c638da 100644 --- a/fs/tracefs/inode.c +++ b/fs/tracefs/inode.c @@ -392,6 +392,9 @@ static int tracefs_reconfigure(struct fs_context *fc) struct tracefs_fs_info *sb_opts = sb->s_fs_info; struct tracefs_fs_info *new_opts = fc->s_fs_info; + if (!new_opts) + return 0; + sync_filesystem(sb); /* structure copy of new mount options to sb */ *sb_opts = *new_opts; @@ -478,14 +481,17 @@ static int tracefs_fill_super(struct super_block *sb, struct fs_context *fc) sb->s_op = &tracefs_super_operations; sb->s_d_op = &tracefs_dentry_operations; - tracefs_apply_options(sb, false); - return 0; } static int tracefs_get_tree(struct fs_context *fc) { - return get_tree_single(fc, tracefs_fill_super); + int err = get_tree_single(fc, tracefs_fill_super); + + if (err) + return err; + + return tracefs_reconfigure(fc); } static void tracefs_free_fc(struct fs_context *fc) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a8f52b6527ca..2b64b3ec67d9 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5501,6 +5501,10 @@ static const struct file_operations tracing_iter_fops = { static const char readme_msg[] = "tracing mini-HOWTO:\n\n" + "By default tracefs removes all OTH file permission bits.\n" + "When mounting tracefs an optional group id can be specified\n" + "which adds the group to every directory and file in tracefs:\n\n" + "\t e.g. mount -t tracefs [-o [gid=]] nodev /sys/kernel/tracing\n\n" "# echo 0 > tracing_on : quick way to disable tracing\n" "# echo 1 > tracing_on : quick way to re-enable tracing\n\n" " Important files:\n" diff --git a/tools/testing/selftests/ftrace/test.d/00basic/mount_options.tc b/tools/testing/selftests/ftrace/test.d/00basic/mount_options.tc new file mode 100644 index 000000000000..35e8d47d6072 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/00basic/mount_options.tc @@ -0,0 +1,101 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Test tracefs GID mount option +# requires: "[gid=]":README + +fail() { + local msg="$1" + + echo "FAILED: $msg" + exit_fail +} + +find_alternate_gid() { + local original_gid="$1" + tac /etc/group | grep -v ":$original_gid:" | head -1 | cut -d: -f3 +} + +mount_tracefs_with_options() { + local mount_point="$1" + local options="$2" + + mount -t tracefs -o "$options" nodev "$mount_point" + + setup +} + +unmount_tracefs() { + local mount_point="$1" + + # Need to make sure the mount isn't busy so that we can umount it + (cd $mount_point; finish_ftrace;) + + cleanup +} + +create_instance() { + local mount_point="$1" + local instance="$mount_point/instances/$(mktemp -u test-XXXXXX)" + + mkdir "$instance" + echo "$instance" +} + +remove_instance() { + local instance="$1" + + rmdir "$instance" +} + +check_gid() { + local mount_point="$1" + local expected_gid="$2" + + echo "Checking permission group ..." + + cd "$mount_point" + + for file in "." "events" "events/sched" "events/sched/sched_switch" "events/sched/sched_switch/enable"; do + local gid=`stat -c "%g" $file` + if [ "$gid" -ne "$expected_gid" ]; then + cd - # Return to the previous working directory (tracefs root) + fail "$(realpath $file): Expected group $expected_gid; Got group $gid" + fi + done + + cd - # Return to the previous working directory (tracefs root) +} + +test_gid_mount_option() { + local mount_point=$(get_mount_point) + local mount_options=$(get_mnt_options "$mount_point") + local original_group=$(stat -c "%g" .) + local other_group=$(find_alternate_gid "$original_group") + + # Set up mount options with new GID for testing + local new_options=`echo "$mount_options" | sed -e "s/gid=[0-9]*/gid=$other_group/"` + if [ "$new_options" = "$mount_options" ]; then + new_options="$mount_options,gid=$other_group" + mount_options="$mount_options,gid=$original_group" + fi + + # Unmount existing tracefs instance and mount with new GID + unmount_tracefs "$mount_point" + mount_tracefs_with_options "$mount_point" "$new_options" + + check_gid "$mount_point" "$other_group" + + # Check that files created after the mount inherit the GID + local instance=$(create_instance "$mount_point") + check_gid "$instance" "$other_group" + remove_instance "$instance" + + # Unmount and remount with the original GID + unmount_tracefs "$mount_point" + mount_tracefs_with_options "$mount_point" "$mount_options" + check_gid "$mount_point" "$original_group" +} + +test_gid_mount_option + +exit 0 diff --git a/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc b/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc index 094419e190c2..e71cc3ad0bdf 100644 --- a/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc +++ b/tools/testing/selftests/ftrace/test.d/00basic/test_ownership.tc @@ -1,24 +1,14 @@ #!/bin/sh # SPDX-License-Identifier: GPL-2.0 # description: Test file and directory ownership changes for eventfs +# requires: "[gid=]":README original_group=`stat -c "%g" .` original_owner=`stat -c "%u" .` -mount_point=`stat -c '%m' .` +local mount_point=$(get_mount_point) -# If stat -c '%m' does not work (e.g. busybox) or failed, try to use the -# current working directory (which should be a tracefs) as the mount point. -if [ ! -d "$mount_point" ]; then - if mount | grep -qw $PWD ; then - mount_point=$PWD - else - # If PWD doesn't work, that is an environmental problem. - exit_unresolved - fi -fi - -mount_options=`mount | grep "$mount_point" | sed -e 's/.*(\(.*\)).*/\1/'` +mount_options=$(get_mnt_options "$mount_point") # find another owner and group that is not the original other_group=`tac /etc/group | grep -v ":$original_group:" | head -1 | cut -d: -f3` diff --git a/tools/testing/selftests/ftrace/test.d/functions b/tools/testing/selftests/ftrace/test.d/functions index 779f3e62ec90..84d6a9c7ad67 100644 --- a/tools/testing/selftests/ftrace/test.d/functions +++ b/tools/testing/selftests/ftrace/test.d/functions @@ -193,3 +193,28 @@ ftrace_errlog_check() { # err-prefix command-with-error-pos-by-^ command-file # " Command: " and "^\n" => 13 test $(expr 13 + $pos) -eq $N } + +# Helper to get the tracefs mount point +get_mount_point() { + local mount_point=`stat -c '%m' .` + + # If stat -c '%m' does not work (e.g. busybox) or failed, try to use the + # current working directory (which should be a tracefs) as the mount point. + if [ ! -d "$mount_point" ]; then + if mount | grep -qw "$PWD"; then + mount_point=$PWD + else + # If PWD doesn't work, that is an environmental problem. + exit_unresolved + fi + fi + echo "$mount_point" +} + +# Helper function to retrieve mount options for a given mount point +get_mnt_options() { + local mnt_point="$1" + local opts=$(mount | grep -m1 "$mnt_point" | sed -e 's/.*(\(.*\)).*/\1/') + + echo "$opts" +} \ No newline at end of file