| Message ID | 160398318667.8898.856205445259063348.stgit@ebuild |
|---|---|
| State | New |
| Headers | show |
| Series | [net] net: openvswitch: silence suspicious RCU usage warning | expand |
On Thu, 29 Oct 2020 15:53:21 +0100 Eelco Chaudron wrote: > Silence suspicious RCU usage warning in ovs_flow_tbl_masks_cache_resize() > by replacing rcu_dereference() with rcu_dereference_ovsl(). > > In addition, when creating a new datapath, make sure it's configured under > the ovs_lock. > > Fixes: 9bf24f594c6a ("net: openvswitch: make masks cache size configurable") > Reported-by: syzbot+9a8f8bfcc56e8578016c@syzkaller.appspotmail.com > Signed-off-by: Eelco Chaudron <echaudro@redhat.com> > --- > net/openvswitch/datapath.c | 8 ++++---- > net/openvswitch/flow_table.c | 2 +- > 2 files changed, 5 insertions(+), 5 deletions(-) > > diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c > index 832f898edb6a..020f8539fede 100644 > --- a/net/openvswitch/datapath.c > +++ b/net/openvswitch/datapath.c > @@ -1695,6 +1695,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) > if (err) > goto err_destroy_ports; > > + /* So far only local changes have been made, now need the lock. */ > + ovs_lock(); Should we move the lock below assignments to param? Looks a little strange to protect stack variables with a global lock. > /* Set up our datapath device. */ > parms.name = nla_data(a[OVS_DP_ATTR_NAME]); > parms.type = OVS_VPORT_TYPE_INTERNAL; > @@ -1707,9 +1710,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) > if (err) > goto err_destroy_meters; > > - /* So far only local changes have been made, now need the lock. */ > - ovs_lock(); > - > vport = new_vport(&parms); > if (IS_ERR(vport)) { > err = PTR_ERR(vport); > @@ -1725,7 +1725,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) > ovs_dp_reset_user_features(skb, info); > } > > - ovs_unlock(); > goto err_destroy_meters; > } > > @@ -1742,6 +1741,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) > return 0; > > err_destroy_meters: Let's update the name of the label. > + ovs_unlock(); > ovs_meters_exit(dp); > err_destroy_ports: > kfree(dp->ports); > diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c > index f3486a37361a..c89c8da99f1a 100644 > --- a/net/openvswitch/flow_table.c > +++ b/net/openvswitch/flow_table.c > @@ -390,7 +390,7 @@ static struct mask_cache *tbl_mask_cache_alloc(u32 size) > } > int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size) > { > - struct mask_cache *mc = rcu_dereference(table->mask_cache); > + struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); > struct mask_cache *new; > > if (size == mc->cache_size) >
On 30 Oct 2020, at 22:28, Jakub Kicinski wrote: > On Thu, 29 Oct 2020 15:53:21 +0100 Eelco Chaudron wrote: >> Silence suspicious RCU usage warning in >> ovs_flow_tbl_masks_cache_resize() >> by replacing rcu_dereference() with rcu_dereference_ovsl(). >> >> In addition, when creating a new datapath, make sure it's configured >> under >> the ovs_lock. >> >> Fixes: 9bf24f594c6a ("net: openvswitch: make masks cache size >> configurable") >> Reported-by: syzbot+9a8f8bfcc56e8578016c@syzkaller.appspotmail.com >> Signed-off-by: Eelco Chaudron <echaudro@redhat.com> >> --- >> net/openvswitch/datapath.c | 8 ++++---- >> net/openvswitch/flow_table.c | 2 +- >> 2 files changed, 5 insertions(+), 5 deletions(-) >> >> diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c >> index 832f898edb6a..020f8539fede 100644 >> --- a/net/openvswitch/datapath.c >> +++ b/net/openvswitch/datapath.c >> @@ -1695,6 +1695,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, >> struct genl_info *info) >> if (err) >> goto err_destroy_ports; >> >> + /* So far only local changes have been made, now need the lock. */ >> + ovs_lock(); > > Should we move the lock below assignments to param? > > Looks a little strange to protect stack variables with a global lock. You are right, I should have moved it down after the assignment. I will send out a v2. >> /* Set up our datapath device. */ >> parms.name = nla_data(a[OVS_DP_ATTR_NAME]); >> parms.type = OVS_VPORT_TYPE_INTERNAL; >> @@ -1707,9 +1710,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, >> struct genl_info *info) >> if (err) >> goto err_destroy_meters; >> >> - /* So far only local changes have been made, now need the lock. */ >> - ovs_lock(); >> - >> vport = new_vport(&parms); >> if (IS_ERR(vport)) { >> err = PTR_ERR(vport); >> @@ -1725,7 +1725,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, >> struct genl_info *info) >> ovs_dp_reset_user_features(skb, info); >> } >> >> - ovs_unlock(); >> goto err_destroy_meters; >> } >> >> @@ -1742,6 +1741,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, >> struct genl_info *info) >> return 0; >> >> err_destroy_meters: > > Let's update the name of the label. Guess now it is, unlock and destroy meters, so what label are you looking for? err_unlock_and_destroy_meters: which looks a bit long, or just err_unlock: >> + ovs_unlock(); >> ovs_meters_exit(dp); >> err_destroy_ports: >> kfree(dp->ports); >> diff --git a/net/openvswitch/flow_table.c >> b/net/openvswitch/flow_table.c >> index f3486a37361a..c89c8da99f1a 100644 >> --- a/net/openvswitch/flow_table.c >> +++ b/net/openvswitch/flow_table.c >> @@ -390,7 +390,7 @@ static struct mask_cache >> *tbl_mask_cache_alloc(u32 size) >> } >> int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 >> size) >> { >> - struct mask_cache *mc = rcu_dereference(table->mask_cache); >> + struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); >> struct mask_cache *new; >> >> if (size == mc->cache_size) >>
On Mon, 02 Nov 2020 09:52:19 +0100 Eelco Chaudron wrote: > On 30 Oct 2020, at 22:28, Jakub Kicinski wrote: > >> @@ -1695,6 +1695,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, > >> struct genl_info *info) > >> if (err) > >> goto err_destroy_ports; > >> > >> + /* So far only local changes have been made, now need the lock. */ > >> + ovs_lock(); > > > > Should we move the lock below assignments to param? > > > > Looks a little strange to protect stack variables with a global lock. > > You are right, I should have moved it down after the assignment. I will > send out a v2. > > > Let's update the name of the label. > > Guess now it is, unlock and destroy meters, so what label are you > looking for? > > err_unlock_and_destroy_meters: which looks a bit long, or just > err_unlock: I feel like I saw some names like err_unlock_and_destroy_meters in OvS code, but can't find them in this file right now. I'd personally go for kist err_unlock, or maybe err_unlock_ovs as is used in other functions in this file. But as long as it starts with err_unlock it's fine by me :)
On 2 Nov 2020, at 20:51, Jakub Kicinski wrote: > On Mon, 02 Nov 2020 09:52:19 +0100 Eelco Chaudron wrote: >> On 30 Oct 2020, at 22:28, Jakub Kicinski wrote: >>>> @@ -1695,6 +1695,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, >>>> struct genl_info *info) >>>> if (err) >>>> goto err_destroy_ports; >>>> >>>> + /* So far only local changes have been made, now need the lock. */ >>>> + ovs_lock(); >>> >>> Should we move the lock below assignments to param? >>> >>> Looks a little strange to protect stack variables with a global lock. >> >> You are right, I should have moved it down after the assignment. I will >> send out a v2. >> >>> Let's update the name of the label. >> >> Guess now it is, unlock and destroy meters, so what label are you >> looking for? >> >> err_unlock_and_destroy_meters: which looks a bit long, or just >> err_unlock: > > I feel like I saw some names like err_unlock_and_destroy_meters in OvS > code, but can't find them in this file right now. > > I'd personally go for kist err_unlock, or maybe err_unlock_ovs as is > used in other functions in this file. > > But as long as it starts with err_unlock it's fine by me :) Ack, sent out a v2.
diff --git a/net/openvswitch/datapath.c b/net/openvswitch/datapath.c index 832f898edb6a..020f8539fede 100644 --- a/net/openvswitch/datapath.c +++ b/net/openvswitch/datapath.c @@ -1695,6 +1695,9 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) if (err) goto err_destroy_ports; + /* So far only local changes have been made, now need the lock. */ + ovs_lock(); + /* Set up our datapath device. */ parms.name = nla_data(a[OVS_DP_ATTR_NAME]); parms.type = OVS_VPORT_TYPE_INTERNAL; @@ -1707,9 +1710,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) if (err) goto err_destroy_meters; - /* So far only local changes have been made, now need the lock. */ - ovs_lock(); - vport = new_vport(&parms); if (IS_ERR(vport)) { err = PTR_ERR(vport); @@ -1725,7 +1725,6 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) ovs_dp_reset_user_features(skb, info); } - ovs_unlock(); goto err_destroy_meters; } @@ -1742,6 +1741,7 @@ static int ovs_dp_cmd_new(struct sk_buff *skb, struct genl_info *info) return 0; err_destroy_meters: + ovs_unlock(); ovs_meters_exit(dp); err_destroy_ports: kfree(dp->ports); diff --git a/net/openvswitch/flow_table.c b/net/openvswitch/flow_table.c index f3486a37361a..c89c8da99f1a 100644 --- a/net/openvswitch/flow_table.c +++ b/net/openvswitch/flow_table.c @@ -390,7 +390,7 @@ static struct mask_cache *tbl_mask_cache_alloc(u32 size) } int ovs_flow_tbl_masks_cache_resize(struct flow_table *table, u32 size) { - struct mask_cache *mc = rcu_dereference(table->mask_cache); + struct mask_cache *mc = rcu_dereference_ovsl(table->mask_cache); struct mask_cache *new; if (size == mc->cache_size)
Silence suspicious RCU usage warning in ovs_flow_tbl_masks_cache_resize() by replacing rcu_dereference() with rcu_dereference_ovsl(). In addition, when creating a new datapath, make sure it's configured under the ovs_lock. Fixes: 9bf24f594c6a ("net: openvswitch: make masks cache size configurable") Reported-by: syzbot+9a8f8bfcc56e8578016c@syzkaller.appspotmail.com Signed-off-by: Eelco Chaudron <echaudro@redhat.com> --- net/openvswitch/datapath.c | 8 ++++---- net/openvswitch/flow_table.c | 2 +- 2 files changed, 5 insertions(+), 5 deletions(-)