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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 fs/proc_namespace.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 8db932d..a5644c4 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -196,17 +196,19 @@ 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Mateusz Guzik]

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 <ldv@altlinux.org>
> ---
>  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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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

Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

[RESEND v2 PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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

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

Suggested-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

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

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

Suggested-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
 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

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

[Dmitry V. Levin]

Date: Wed Nov 18 21:09:45 2015 +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.

Suggested-by: Mateusz Guzik <mguzik@redhat.com>
Signed-off-by: Dmitry V. Levin <ldv@altlinux.org>
---
 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

[RESEND v3 PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 fs/proc_namespace.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 2256e7e..3f1190d 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -190,26 +190,28 @@ out:
 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
 {
 	struct proc_mounts *p = m->private;
 	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;
 
 	/* device */
 	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

[RESEND v4 PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

[Dmitry V. Levin]

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 <ldv@altlinux.org>
---
 fs/proc_namespace.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/proc_namespace.c b/fs/proc_namespace.c
index 2256e7e..3f1190d 100644
--- a/fs/proc_namespace.c
+++ b/fs/proc_namespace.c
@@ -190,26 +190,28 @@ out:
 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
 {
 	struct proc_mounts *p = m->private;
 	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;
 
 	/* device */
 	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

Re: [RESEND v4 PATCH] vfs: show_vfsstat: do not ignore errors from show_devname method

[Al Viro]

On Wed, Mar 16, 2016 at 07:31:22PM +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.

Applied weeks ago, still not migrated into for-next; my apologies, thought
I pushed it to Linus at some point last cycle.  I'll take it to for-next
in a few.