2011-02-04 15:28:50

by Andrei Vagin

Subject: [PATCH 1/2] fs: Correctly check d_find_alias() return code in devpts_pty_kill

d_find_alias() return NULL in case error, but we expected errno in
devpts_pty_kill.

Signed-off-by: Andrey Vagin <[email protected]>
---
fs/devpts/inode.c | 10 ++++------
1 files changed, 4 insertions(+), 6 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 8392c8c..530b1f1 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -544,14 +544,12 @@ void devpts_pty_kill(struct tty_struct *tty)
mutex_lock(&root->d_inode->i_mutex);

dentry = d_find_alias(inode);
- if (IS_ERR(dentry))
+ if (!dentry)
goto out;

- if (dentry) {
- inode->i_nlink--;
- d_delete(dentry);
- dput(dentry); /* d_alloc_name() in devpts_pty_new() */
- }
+ inode->i_nlink--;
+ d_delete(dentry);
+ dput(dentry); /* d_alloc_name() in devpts_pty_new() */

dput(dentry); /* d_find_alias above */
out:
--
1.7.2.1

2011-02-04 15:28:45

by Andrei Vagin

Subject: [PATCH 2/2] fs: devpts_pty_new() return -ENOMEM if dentry allocation failed

In this case nobody can open a slave point, so will be better return error
from devpts_pty_new()

Signed-off-by: Andrey Vagin <[email protected]>
---
fs/devpts/inode.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
index 530b1f1..31474f3 100644
--- a/fs/devpts/inode.c
+++ b/fs/devpts/inode.c
@@ -479,6 +479,7 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
struct dentry *root = sb->s_root;
struct pts_fs_info *fsi = DEVPTS_SB(sb);
struct pts_mount_opts *opts = &fsi->mount_opts;
+ int ret = 0;
char s[12];

/* We're supposed to be given the slave end of a pty */
@@ -504,11 +505,14 @@ int devpts_pty_new(struct inode *ptmx_inode, struct tty_struct *tty)
if (dentry) {
d_add(dentry, inode);
fsnotify_create(root->d_inode, dentry);
+ } else {
+ iput(inode);
+ ret = -ENOMEM;
}

mutex_unlock(&root->d_inode->i_mutex);

- return 0;
+ return ret;
}

struct tty_struct *devpts_get_tty(struct inode *pts_inode, int number)
--
1.7.2.1

2011-02-04 18:11:28

by J. Bruce Fields

Subject: Re: [PATCH 1/2] fs: Correctly check d_find_alias() return code in devpts_pty_kill

On Fri, Feb 04, 2011 at 06:28:26PM +0300, Andrey Vagin wrote:
> d_find_alias() return NULL in case error, but we expected errno in
> devpts_pty_kill.

Possibly dumb question: can d_find_alias() actually fail here?

--b.

>
> Signed-off-by: Andrey Vagin <[email protected]>
> ---
> fs/devpts/inode.c | 10 ++++------
> 1 files changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/fs/devpts/inode.c b/fs/devpts/inode.c
> index 8392c8c..530b1f1 100644
> --- a/fs/devpts/inode.c
> +++ b/fs/devpts/inode.c
> @@ -544,14 +544,12 @@ void devpts_pty_kill(struct tty_struct *tty)
> mutex_lock(&root->d_inode->i_mutex);
>
> dentry = d_find_alias(inode);
> - if (IS_ERR(dentry))
> + if (!dentry)
> goto out;
>
> - if (dentry) {
> - inode->i_nlink--;
> - d_delete(dentry);
> - dput(dentry); /* d_alloc_name() in devpts_pty_new() */
> - }
> + inode->i_nlink--;
> + d_delete(dentry);
> + dput(dentry); /* d_alloc_name() in devpts_pty_new() */
>
> dput(dentry); /* d_find_alias above */
> out:
> --
> 1.7.2.1
>
> --
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