2020-02-21 18:10:14

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 | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/core/devlink.c b/net/core/devlink.c
index 3e8c94155d93..d54e1f156b6f 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -6840,6 +6840,8 @@ int devlink_dpipe_table_register(struct devlink *devlink,
{
struct devlink_dpipe_table *table;

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

@@ -6855,7 +6857,6 @@ int devlink_dpipe_table_register(struct devlink *devlink,
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

2020-02-22 06:29:20

by Jiri Pirko

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

Fri, Feb 21, 2020 at 07:09:43PM 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 | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/net/core/devlink.c b/net/core/devlink.c
>index 3e8c94155d93..d54e1f156b6f 100644
>--- a/net/core/devlink.c
>+++ b/net/core/devlink.c
>@@ -6840,6 +6840,8 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> {
> struct devlink_dpipe_table *table;
>
>+ mutex_lock(&devlink->lock);
>+
> if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
> return -EEXIST;

You have to handle the error path.


>
>@@ -6855,7 +6857,6 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> 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
>

2020-02-22 06:58:04

by Madhuparna Bhowmik

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

On Sat, Feb 22, 2020 at 07:26:40AM +0100, Jiri Pirko wrote:
> Fri, Feb 21, 2020 at 07:09:43PM 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 | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> >diff --git a/net/core/devlink.c b/net/core/devlink.c
> >index 3e8c94155d93..d54e1f156b6f 100644
> >--- a/net/core/devlink.c
> >+++ b/net/core/devlink.c
> >@@ -6840,6 +6840,8 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> > {
> > struct devlink_dpipe_table *table;
> >
> >+ mutex_lock(&devlink->lock);
> >+
> > if (devlink_dpipe_table_find(&devlink->dpipe_table_list, table_name))
> > return -EEXIST;
>
> You have to handle the error path.
>
Sure, I have sent the updated patch.

Thank you,
Madhuparna
>
> >
> >@@ -6855,7 +6857,6 @@ int devlink_dpipe_table_register(struct devlink *devlink,
> > 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
> >