| Message ID | a59d4d9295e40fe6cfaa0803c5a7cc6e80e7b1a2.1674233458.git.dcaratti@redhat.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 78dcdffe0418ac8f3f057f26fe71ccf4d8ed851f |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | net/sched: use the backlog for nested mirred ingress | expand |
On Fri, Jan 20, 2023 at 06:01:39PM +0100, Davide Caratti wrote: > with commit e2ca070f89ec ("net: sched: protect against stack overflow in > TC act_mirred"), act_mirred protected itself against excessive stack growth > using per_cpu counter of nested calls to tcf_mirred_act(), and capping it > to MIRRED_RECURSION_LIMIT. However, such protection does not detect > recursion/loops in case the packet is enqueued to the backlog (for example, > when the mirred target device has RPS or skb timestamping enabled). Change > the wording from "recursion" to "nesting" to make it more clear to readers. > > CC: Jamal Hadi Salim <jhs@mojatatu.com> > Signed-off-by: Davide Caratti <dcaratti@redhat.com> Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
On Mon, Jan 23, 2023 at 12:22 PM Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> wrote: > > On Fri, Jan 20, 2023 at 06:01:39PM +0100, Davide Caratti wrote: > > with commit e2ca070f89ec ("net: sched: protect against stack overflow in > > TC act_mirred"), act_mirred protected itself against excessive stack growth > > using per_cpu counter of nested calls to tcf_mirred_act(), and capping it > > to MIRRED_RECURSION_LIMIT. However, such protection does not detect > > recursion/loops in case the packet is enqueued to the backlog (for example, > > when the mirred target device has RPS or skb timestamping enabled). Change > > the wording from "recursion" to "nesting" to make it more clear to readers. > > > > CC: Jamal Hadi Salim <jhs@mojatatu.com> > > Signed-off-by: Davide Caratti <dcaratti@redhat.com> > > Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com> Acked-by: Jamal Hadi Salim <jhs@mojatatu.com> cheers, jamal
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 7284bcea7b0b..c8abb5136491 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -29,8 +29,8 @@ static LIST_HEAD(mirred_list); static DEFINE_SPINLOCK(mirred_list_lock); -#define MIRRED_RECURSION_LIMIT 4 -static DEFINE_PER_CPU(unsigned int, mirred_rec_level); +#define MIRRED_NEST_LIMIT 4 +static DEFINE_PER_CPU(unsigned int, mirred_nest_level); static bool tcf_mirred_is_act_redirect(int action) { @@ -226,7 +226,7 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, struct sk_buff *skb2 = skb; bool m_mac_header_xmit; struct net_device *dev; - unsigned int rec_level; + unsigned int nest_level; int retval, err = 0; bool use_reinsert; bool want_ingress; @@ -237,11 +237,11 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, int mac_len; bool at_nh; - rec_level = __this_cpu_inc_return(mirred_rec_level); - if (unlikely(rec_level > MIRRED_RECURSION_LIMIT)) { + nest_level = __this_cpu_inc_return(mirred_nest_level); + if (unlikely(nest_level > MIRRED_NEST_LIMIT)) { net_warn_ratelimited("Packet exceeded mirred recursion limit on dev %s\n", netdev_name(skb->dev)); - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return TC_ACT_SHOT; } @@ -310,7 +310,7 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, err = tcf_mirred_forward(want_ingress, skb); if (err) tcf_action_inc_overlimit_qstats(&m->common); - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return TC_ACT_CONSUMED; } } @@ -322,7 +322,7 @@ TC_INDIRECT_SCOPE int tcf_mirred_act(struct sk_buff *skb, if (tcf_mirred_is_act_redirect(m_eaction)) retval = TC_ACT_SHOT; } - __this_cpu_dec(mirred_rec_level); + __this_cpu_dec(mirred_nest_level); return retval; }
with commit e2ca070f89ec ("net: sched: protect against stack overflow in TC act_mirred"), act_mirred protected itself against excessive stack growth using per_cpu counter of nested calls to tcf_mirred_act(), and capping it to MIRRED_RECURSION_LIMIT. However, such protection does not detect recursion/loops in case the packet is enqueued to the backlog (for example, when the mirred target device has RPS or skb timestamping enabled). Change the wording from "recursion" to "nesting" to make it more clear to readers. CC: Jamal Hadi Salim <jhs@mojatatu.com> Signed-off-by: Davide Caratti <dcaratti@redhat.com> --- net/sched/act_mirred.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)