2020-02-22 06:53:30

by Madhuparna Bhowmik

Subject: [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()

From: Madhuparna Bhowmik <[email protected]>

devlink_dpipe_table_find() should be called under either
rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
calls devlink_dpipe_table_find() without holding the lock
and acquires it later. Therefore hold the devlink->lock
from the beginning of devlink_dpipe_table_register().

Suggested-by: Jiri Pirko <[email protected]>
Signed-off-by: Madhuparna Bhowmik <[email protected]>
---
net/core/devlink.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 3e8c94155d93..ba9dd8cb98c3 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6840,22 +6840,29 @@ int devlink_dpipe_table_register(struct devlink *devlink,
{
struct devlink_dpipe_table *table;

- if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
+ mutex_lock(&devlink->lock);
+
+ if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
+ mutex_unlock(&devlink->lock);
return -EEXIST;
+ }

- if (WARN_ON(!table_ops->size_get))
+ if (WARN_ON(!table_ops->size_get)) {
+ mutex_unlock(&devlink->lock);
return -EINVAL;
+ }

table = kzalloc(sizeof(*table), GFP_KERNEL);
- if (!table)
+ if (!table) {
+ mutex_unlock(&devlink->lock);
return -ENOMEM;
+ }

table->name = table_name;
table->table_ops = table_ops;
table->priv = priv;
table->counter_control_extern = counter_control_extern;

- mutex_lock(&devlink->lock);
list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
mutex_unlock(&devlink->lock);
return 0;
--
2.17.1

2020-02-23 06:44:09

by Jiri Pirko

Subject: Re: [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()

Sat, Feb 22, 2020 at 07:52:34AM CET, [email protected] wrote:
>From: Madhuparna Bhowmik <[email protected]>
>
>devlink_dpipe_table_find() should be called under either
>rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
>calls devlink_dpipe_table_find() without holding the lock
>and acquires it later. Therefore hold the devlink->lock
>from the beginning of devlink_dpipe_table_register().
>
>Suggested-by: Jiri Pirko <[email protected]>
>Signed-off-by: Madhuparna Bhowmik <[email protected]>
>---
> net/core/devlink.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 3e8c94155d93..ba9dd8cb98c3 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -6840,22 +6840,29 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> {
> struct devlink_dpipe_table *table;
>
>- if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
>+ mutex_lock(&devlink->lock);
>+
>+ if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
>+ mutex_unlock(&devlink->lock);
> return -EEXIST;
>+ }
>
>- if (WARN_ON(!table_ops->size_get))
>+ if (WARN_ON(!table_ops->size_get)) {
>+ mutex_unlock(&devlink->lock);
> return -EINVAL;
>+ }
>
> table = kzalloc(sizeof(*table), GFP_KERNEL);
>- if (!table)
>+ if (!table) {
>+ mutex_unlock(&devlink->lock);

Please use "goto unlock" instead of unlocking on multiple places.



> return -ENOMEM;
>+ }
>
> table->name = table_name;
> table->table_ops = table_ops;
> table->priv = priv;
> table->counter_control_extern = counter_control_extern;
>
>- mutex_lock(&devlink->lock);
> list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
> mutex_unlock(&devlink->lock);
> return 0;
>--
>2.17.1
>

2020-02-23 10:56:49

by Madhuparna Bhowmik

Subject: Re: [PATCH] net: core: devlink.c: Hold devlink->lock from the beginning of devlink_dpipe_table_register()

On Sun, Feb 23, 2020 at 07:43:29AM +0100, Jiri Pirko wrote:
> Sat, Feb 22, 2020 at 07:52:34AM CET, [email protected] wrote:
> >From: Madhuparna Bhowmik <[email protected]>
> >
> >devlink_dpipe_table_find() should be called under either
> >rcu_read_lock() or devlink->lock. devlink_dpipe_table_register()
> >calls devlink_dpipe_table_find() without holding the lock
> >and acquires it later. Therefore hold the devlink->lock
> >from the beginning of devlink_dpipe_table_register().
> >
> >Suggested-by: Jiri Pirko <[email protected]>
> >Signed-off-by: Madhuparna Bhowmik <[email protected]>
> >---
> > net/core/devlink.c | 15 +++++++++++----
> > 1 file changed, 11 insertions(+), 4 deletions(-)
> >
> >diff --git a/net/core/devlink.c b/net/core/devlink.c
> >index 3e8c94155d93..ba9dd8cb98c3 100644
> >--- a/net/core/devlink.c
> >+++ b/net/core/devlink.c
> >@@ -6840,22 +6840,29 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> > {
> > struct devlink_dpipe_table *table;
> >
> >- if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
> >+ mutex_lock(&devlink->lock);
> >+
> >+ if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name)) {
> >+ mutex_unlock(&devlink->lock);
> > return -EEXIST;
> >+ }
> >
> >- if (WARN_ON(!table_ops->size_get))
> >+ if (WARN_ON(!table_ops->size_get)) {
> >+ mutex_unlock(&devlink->lock);
> > return -EINVAL;
> >+ }
> >
> > table = kzalloc(sizeof(*table), GFP_KERNEL);
> >- if (!table)
> >+ if (!table) {
> >+ mutex_unlock(&devlink->lock);
>
> Please use "goto unlock" instead of unlocking on multiple places.
>
Sure, I have sent a new patch.
Thank you,
Madhuparna
>
>
> > return -ENOMEM;
> >+ }
> >
> > table->name = table_name;
> > table->table_ops = table_ops;
> > table->priv = priv;
> > table->counter_control_extern = counter_control_extern;
> >
> >- mutex_lock(&devlink->lock);
> > list_add_tail_rcu(&table->list, &devlink->dpipe_table_list);
> > mutex_unlock(&devlink->lock);
> > return 0;
> >--
> >2.17.1
> >