Commit 99663be7 authored Apr 05, 2012 by Vasiliy Kulikov Committed by Linus Torvalds Apr 05, 2012

proc: fix mount -t proc -o AAA



The proc_parse_options() call from proc_mount() runs only once at boot
time.  So on any later mount attempt, any mount options are ignored
because ->s_root is already initialized.

As a consequence, "mount -o <options>" will ignore the options.  The
only way to change mount options is "mount -o remount,<options>".

To fix this, parse the mount options unconditionally.

Signed-off-by: Vasiliy Kulikov <segoon@openwall.com>
Reported-by: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Tested-by: Arkadiusz Miskiewicz <a.miskiewicz@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 10bdfb5e

fs/proc/root.c

+5 −4

Original line number	Original line	Diff line number	Diff line
	@@ -115,12 +115,13 @@ static struct dentry proc_mount(struct file_system_type fs_type,
	if (IS_ERR(sb))		if (IS_ERR(sb))
	return ERR_CAST(sb);		return ERR_CAST(sb);

	if (!sb->s_root) {
	sb->s_flags = flags;
	if (!proc_parse_options(options, ns)) {		if (!proc_parse_options(options, ns)) {
	deactivate_locked_super(sb);		deactivate_locked_super(sb);
	return ERR_PTR(-EINVAL);		return ERR_PTR(-EINVAL);
	}		}

			if (!sb->s_root) {
			sb->s_flags = flags;
	err = proc_fill_super(sb);		err = proc_fill_super(sb);
	if (err) {		if (err) {
	deactivate_locked_super(sb);		deactivate_locked_super(sb);

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