linux-stable.git/fs/debugfs/inode.c, branch v3.4.112

debugfs: leave freeing a symlink body until inode eviction

2015-06-19T03:40:18+00:00

commit 0db59e59299f0b67450c5db21f7f316c8fb04e84 upstream.

As it is, we have debugfs_remove() racing with symlink traversals.
Supply ->evict_inode() and do freeing there - inode will remain
pinned until we are done with the symlink body.

And rip the idiocy with checking if dentry is positive right after
we'd verified debugfs_positive(), which is a stronger check...

Signed-off-by: Al Viro 
[lizf: Backported to 3.4:
 - call end_writeback() instead of clear_inode()
 - call truncate_inode_pages() instead of truncate_inode_pages_final()]
Signed-off-by: Zefan Li

move d_rcu from overlapping d_child to overlapping d_alias

2015-04-14T09:33:58+00:00

commit 946e51f2bf37f1656916eb75bd0742ba33983c28 upstream.

Signed-off-by: Al Viro 
[bwh: Backported to 3.2:
 - Apply name changes in all the different places we use d_alias and d_child
 - Move the WARN_ON() in __d_free() to d_free() as we don't have dentry_free()]
Signed-off-by: Ben Hutchings 
[lizf: Backported to 3.4:
 - adjust context
 - need one more name change in debugfs]

debugfs: debugfs_remove_recursive() must not rely on list_empty(d_subdirs)

2013-08-15T05:57:07+00:00

commit 776164c1faac4966ab14418bb0922e1820da1d19 upstream.

debugfs_remove_recursive() is wrong,

1. it wrongly assumes that !list_empty(d_subdirs) means that this
   dir should be removed.

   This is not that bad by itself, but:

2. if d_subdirs does not becomes empty after __debugfs_remove()
   it gives up and silently fails, it doesn't even try to remove
   other entries.

   However ->d_subdirs can be non-empty because it still has the
   already deleted !debugfs_positive() entries.

3. simple_release_fs() is called even if __debugfs_remove() fails.

Suppose we have

	dir1/
		dir2/
			file2
		file1

and someone opens dir1/dir2/file2.

Now, debugfs_remove_recursive(dir1/dir2) succeeds, and dir1/dir2 goes
away.

But debugfs_remove_recursive(dir1) silently fails and doesn't remove
this directory. Because it tries to delete (the already deleted)
dir1/dir2/file2 again and then fails due to "Avoid infinite loop"
logic.

Test-case:

	#!/bin/sh

	cd /sys/kernel/debug/tracing
	echo 'p:probe/sigprocmask sigprocmask' >> kprobe_events
	sleep 1000 < events/probe/sigprocmask/id &
	echo -n >| kprobe_events

	[ -d events/probe ] && echo "ERR!! failed to rm probe"

And after that it is not possible to create another probe entry.

With this patch debugfs_remove_recursive() skips !debugfs_positive()
files although this is not strictly needed. The most important change
is that it does not try to make ->d_subdirs empty, it simply scans
the whole list(s) recursively and removes as much as possible.

Link: http://lkml.kernel.org/r/20130726151256.GC19472@redhat.com

Acked-by: Greg Kroah-Hartman 
Signed-off-by: Oleg Nesterov 
Signed-off-by: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

debugfs: add mode, uid and gid options

2012-01-26T19:28:49+00:00

Cautious admins may want to restrict access to debugfs. Currently a
manual chown/chmod e.g. in an init script is needed to achieve that.
Distributions that want to make the mount options configurable need
to add extra config files. By allowing to set the root inode's uid,
gid and mode via mount options no such hacks are needed anymore.
Instead configuration becomes straight forward via fstab.

Signed-off-by: Ludwig Nussel 
Signed-off-by: Greg Kroah-Hartman

switch debugfs to umode_t

2012-01-04T03:54:56+00:00

Signed-off-by: Al Viro

vfs: for usbfs, etc. internal vfsmounts ->mnt_sb->s_root == ->mnt_root

2012-01-04T03:52:41+00:00

Signed-off-by: Al Viro

debugfs: Fix a comment mistake

2011-08-23T00:41:48+00:00

The file is fs/debugfs/inode.c but the comment says it is file.c.
This patch can fix this little mistake.

Signed-off-by: Harry Wei 
Signed-off-by: Greg Kroah-Hartman

debugfs: Fix filesystem reference counting on debugfs_remove() failure

2011-02-18T16:07:18+00:00

When __debugfs_remove() fails (because simple_rmdir() fails e.g. when a
directory is not empty), we must not decrement use count of the filesystem
as nothing was in fact deleted.

This fixes use after free caused by debugfs in some cases.

Signed-off-by: Jan Kara 
Signed-off-by: Greg Kroah-Hartman

debugfs: remove module_exit()

2011-02-03T23:39:17+00:00

debugfs can't be a module, so module_exit() is meaningless for it.

Signed-off-by: WANG Cong 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

convert get_sb_single() users

2010-10-29T08:16:28+00:00

Signed-off-by: Al Viro