2015-11-18 17:51:13

by Dmitry V. Levin

Subject: [RESEND PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

Date: Thu, 19 Mar 2015 11:10:54 +0000

Explicitly check show_devname method return code and bail out in case
of an error. This fixes regression introduced by commit 9d4d65748a5c.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 8ebd9a3..876459559 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -197,17 +197,19 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
if (sb->s_op->show_devname) {
seq_puts(m, "device ");
err = sb->s_op->show_devname(m, mnt_path.dentry);
+ if (err)
+ goto out;
} else {
if (r->mnt_devname) {
seq_puts(m, "device ");
mangle(m, r->mnt_devname);
} else
seq_puts(m, "no device");
}

/* mount point */
seq_puts(m, " mounted on ");
/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
if (err)
goto out;

--
ldv

2015-11-18 18:02:24

by Mateusz Guzik

Subject: Re: [RESEND PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

On Wed, Nov 18, 2015 at 08:42:48PM +0300, Dmitry V. Levin wrote:
> Date: Thu, 19 Mar 2015 11:10:54 +0000
>
> Explicitly check show_devname method return code and bail out in case
> of an error. This fixes regression introduced by commit 9d4d65748a5c.
>
> Signed-off-by: Dmitry V. Levin <[email protected]>
> ---
> fs/proc_namespace.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
> index 8ebd9a3..876459559 100644
> --- a/fs/proc_namespace.c
> +++ b/fs/proc_namespace.c
> @@ -197,17 +197,19 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
> if (sb->s_op->show_devname) {
> seq_puts(m, "device ");
> err = sb->s_op->show_devname(m, mnt_path.dentry);
> + if (err)
> + goto out;
> } else {
> if (r->mnt_devname) {
> seq_puts(m, "device ");
> mangle(m, r->mnt_devname);
> } else
> seq_puts(m, "no device");
> }
>
> /* mount point */
> seq_puts(m, " mounted on ");
> /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
> err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
> if (err)
> goto out;
>

I would suggest this should also remove now spurious initialization of
err to 0 and now always-true !err check prior to calling ->show_stats.

--
Mateusz Guzik

2015-11-18 21:57:55

by Dmitry V. Levin

Subject: [PATCH 1/3] vfs: show_vfsmnt: remove redundant initialization of error code

As err variable is now always checked right after the first assignment,
its initialization is redundant and could be safely removed.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 876459559..cbc9c27 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -95,9 +95,9 @@ static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
{
struct proc_mounts *p = m->private;
struct mount *r = real_mount(mnt);
- int err = 0;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
+ int err;

if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt_path.dentry);

--
ldv

2015-11-18 21:58:23

by Dmitry V. Levin

Subject: [PATCH 2/3] vfs: show_mountinfo: cleanup error code checks

Check err variable right after each assignment. This change makes
initialization of err redundant, so remove the initialization.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index cbc9c27..7a6b2f3 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -131,16 +131,17 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
struct mount *r = real_mount(mnt);
struct super_block *sb = mnt->mnt_sb;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
- int err = 0;
+ int err;

seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev));
- if (sb->s_op->show_path)
+ if (sb->s_op->show_path) {
err = sb->s_op->show_path(m, mnt->mnt_root);
- else
+ if (err)
+ goto out;
+ } else {
seq_dentry(m, mnt->mnt_root, " \t\n\\");
- if (err)
- goto out;
+ }
seq_putc(m, ' ');

/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
@@ -168,12 +169,13 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
- if (sb->s_op->show_devname)
+ if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt->mnt_root);
- else
+ if (err)
+ goto out;
+ } else {
mangle(m, r->mnt_devname ? r->mnt_devname : "none");
- if (err)
- goto out;
+ }
seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)

--
ldv

2015-11-18 21:58:36

by Dmitry V. Levin

Subject: [PATCH 3/3] vfs: show_vfsstat: remove redundant initialization and check of error code

As err variable is now always checked right after each assignment, its
initialization is redundant and could be safely removed. For the same
reason, the last check of err is also redundant and could be removed as
well.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 7a6b2f3..3f1190d 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -193,7 +193,7 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
struct mount *r = real_mount(mnt);
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
- int err = 0;
+ int err;

/* device */
if (sb->s_op->show_devname) {
@@ -224,8 +224,7 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
/* optional statistics */
if (sb->s_op->show_stats) {
seq_putc(m, ' ');
- if (!err)
- err = sb->s_op->show_stats(m, mnt_path.dentry);
+ err = sb->s_op->show_stats(m, mnt_path.dentry);
}

seq_putc(m, '\n');

--
ldv

2015-12-02 17:26:35

by Dmitry V. Levin

Subject: [RESEND v2 PATCH 1/4] vfs: show_vfsstat: do not ignore errors from show_devname method

Date: Thu, 19 Mar 2015 11:10:54 +0000

Explicitly check show_devname method return code and bail out in case
of an error. This fixes regression introduced by commit 9d4d65748a5c.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 8ebd9a3..876459559 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -197,17 +197,19 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
if (sb->s_op->show_devname) {
seq_puts(m, "device ");
err = sb->s_op->show_devname(m, mnt_path.dentry);
+ if (err)
+ goto out;
} else {
if (r->mnt_devname) {
seq_puts(m, "device ");
mangle(m, r->mnt_devname);
} else
seq_puts(m, "no device");
}

/* mount point */
seq_puts(m, " mounted on ");
/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
if (err)
goto out;

--
ldv

2015-12-02 17:24:56

by Dmitry V. Levin

Subject: [RESEND PATCH 2/4] vfs: show_vfsmnt: remove redundant initialization of error code

Date: Wed, 18 Nov 2015 21:07:10 +0000

As err variable is now always checked right after the first assignment,
its initialization is redundant and could be safely removed.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 876459559..cbc9c27 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -95,9 +95,9 @@ static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
{
struct proc_mounts *p = m->private;
struct mount *r = real_mount(mnt);
- int err = 0;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
+ int err;

if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt_path.dentry);

--
ldv

2015-12-02 17:23:45

by Dmitry V. Levin

Subject: [RESEND PATCH 3/4] vfs: show_mountinfo: cleanup error code checks

Wed, 18 Nov 2015 21:08:33 +0000

Check err variable right after each assignment. This change makes
initialization of err redundant, so remove the initialization.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index cbc9c27..7a6b2f3 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -131,16 +131,17 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
struct mount *r = real_mount(mnt);
struct super_block *sb = mnt->mnt_sb;
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
- int err = 0;
+ int err;

seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
MAJOR(sb->s_dev), MINOR(sb->s_dev));
- if (sb->s_op->show_path)
+ if (sb->s_op->show_path) {
err = sb->s_op->show_path(m, mnt->mnt_root);
- else
+ if (err)
+ goto out;
+ } else {
seq_dentry(m, mnt->mnt_root, " \t\n\\");
- if (err)
- goto out;
+ }
seq_putc(m, ' ');

/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
@@ -168,12 +169,13 @@ static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
seq_puts(m, " - ");
show_type(m, sb);
seq_putc(m, ' ');
- if (sb->s_op->show_devname)
+ if (sb->s_op->show_devname) {
err = sb->s_op->show_devname(m, mnt->mnt_root);
- else
+ if (err)
+ goto out;
+ } else {
mangle(m, r->mnt_devname ? r->mnt_devname : "none");
- if (err)
- goto out;
+ }
seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
err = show_sb_opts(m, sb);
if (err)

--
ldv

2015-12-02 17:21:04

by Dmitry V. Levin

Subject: [RESEND PATCH 4/4] vfs: show_vfsstat: remove redundant initialization and check of error code

Date: Wed, 18 Nov 2015 21:09:45 +0000

As err variable is now always checked right after each assignment, its
initialization is redundant and could be safely removed. For the same
reason, the last check of err is also redundant and could be removed as
well.

Signed-off-by: Dmitry V. Levin <[email protected]>
---
fs/proc_namespace.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 7a6b2f3..3f1190d 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -193,7 +193,7 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
struct mount *r = real_mount(mnt);
struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
struct super_block *sb = mnt_path.dentry->d_sb;
- int err = 0;
+ int err;

/* device */
if (sb->s_op->show_devname) {
@@ -224,8 +224,7 @@ static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
/* optional statistics */
if (sb->s_op->show_stats) {
seq_putc(m, ' ');
- if (!err)
- err = sb->s_op->show_stats(m, mnt_path.dentry);
+ err = sb->s_op->show_stats(m, mnt_path.dentry);
}

seq_putc(m, '\n');

--
ldv