Re: [PATCH 4.4 06/34] sget(): handle failures of register_shrinker()

[Ben Hutchings]

On Fri, 2018-03-02 at 09:51 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> --
> 
> From: Al Viro 
> 
> 
> [ Upstream commit 9ee332d99e4d5a97548943b81c54668450ce641b ]
> 
> Signed-off-by: Al Viro 
> Signed-off-by: Sasha Levin 
> Signed-off-by: Greg Kroah-Hartman 
> ---
>  fs/super.c |6 +-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -497,7 +497,11 @@ retry:
>   hlist_add_head(>s_instances, >fs_supers);
>   spin_unlock(_lock);
>   get_filesystem(type);
> - register_shrinker(>s_shrink);
> + err = register_shrinker(>s_shrink);
> + if (err) {
> + deactivate_locked_super(s);

But deactivate_locked_super() will call unregister_shrinker(), which
doesn't look safe if register_shrinker() failed.

Ben.

> + s = ERR_PTR(err);
> + }
>   return s;
>  }
>  
> 
> 
> 
-- 
Ben Hutchings
Software Developer, Codethink Ltd.

Re: [PATCH 4.4 06/34] sget(): handle failures of register_shrinker()

[Ben Hutchings]

On Fri, 2018-03-02 at 09:51 +0100, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> --
> 
> From: Al Viro 
> 
> 
> [ Upstream commit 9ee332d99e4d5a97548943b81c54668450ce641b ]
> 
> Signed-off-by: Al Viro 
> Signed-off-by: Sasha Levin 
> Signed-off-by: Greg Kroah-Hartman 
> ---
>  fs/super.c |6 +-
>  1 file changed, 5 insertions(+), 1 deletion(-)
> 
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -497,7 +497,11 @@ retry:
>   hlist_add_head(>s_instances, >fs_supers);
>   spin_unlock(_lock);
>   get_filesystem(type);
> - register_shrinker(>s_shrink);
> + err = register_shrinker(>s_shrink);
> + if (err) {
> + deactivate_locked_super(s);

But deactivate_locked_super() will call unregister_shrinker(), which
doesn't look safe if register_shrinker() failed.

Ben.

> + s = ERR_PTR(err);
> + }
>   return s;
>  }
>  
> 
> 
> 
-- 
Ben Hutchings
Software Developer, Codethink Ltd.

[PATCH 4.4 06/34] sget(): handle failures of register_shrinker()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Al Viro 


[ Upstream commit 9ee332d99e4d5a97548943b81c54668450ce641b ]

Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 fs/super.c |6 +-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/super.c
+++ b/fs/super.c
@@ -497,7 +497,11 @@ retry:
hlist_add_head(>s_instances, >fs_supers);
spin_unlock(_lock);
get_filesystem(type);
-   register_shrinker(>s_shrink);
+   err = register_shrinker(>s_shrink);
+   if (err) {
+   deactivate_locked_super(s);
+   s = ERR_PTR(err);
+   }
return s;
 }
 

[PATCH 4.4 06/34] sget(): handle failures of register_shrinker()

[Greg Kroah-Hartman]

4.4-stable review patch.  If anyone has any objections, please let me know.

--

From: Al Viro 


[ Upstream commit 9ee332d99e4d5a97548943b81c54668450ce641b ]

Signed-off-by: Al Viro 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman 
---
 fs/super.c |6 +-
 1 file changed, 5 insertions(+), 1 deletion(-)

--- a/fs/super.c
+++ b/fs/super.c
@@ -497,7 +497,11 @@ retry:
hlist_add_head(>s_instances, >fs_supers);
spin_unlock(_lock);
get_filesystem(type);
-   register_shrinker(>s_shrink);
+   err = register_shrinker(>s_shrink);
+   if (err) {
+   deactivate_locked_super(s);
+   s = ERR_PTR(err);
+   }
return s;
 }