* [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type
@ 2019-10-19 11:19 Toke Høiland-Jørgensen
2019-10-21 15:56 ` Martin Lau
2019-10-21 22:50 ` Alexei Starovoitov
0 siblings, 2 replies; 3+ messages in thread
From: Toke Høiland-Jørgensen @ 2019-10-19 11:19 UTC (permalink / raw)
To: daniel, ast
Cc: Toke Høiland-Jørgensen, bpf, netdev, kafai, Tetsuo Handa
It seems I forgot to add handling of devmap_hash type maps to the device
unregister hook for devmaps. This omission causes devices to not be
properly released, which causes hangs.
Fix this by adding the missing handler.
Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
---
v4:
- Don't forget to decrement dtab->items when removing item from map
v3:
- Use u32 for loop iterator variable
- Since we're holding the lock we can just iterate with hlist_for_each_entry_safe()
v2:
- Grab the update lock while walking the map and removing entries.
kernel/bpf/devmap.c | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c
index c0a48f336997..3867864cdc2f 100644
--- a/kernel/bpf/devmap.c
+++ b/kernel/bpf/devmap.c
@@ -719,6 +719,32 @@ const struct bpf_map_ops dev_map_hash_ops = {
.map_check_btf = map_check_no_btf,
};
+static void dev_map_hash_remove_netdev(struct bpf_dtab *dtab,
+ struct net_device *netdev)
+{
+ unsigned long flags;
+ u32 i;
+
+ spin_lock_irqsave(&dtab->index_lock, flags);
+ for (i = 0; i < dtab->n_buckets; i++) {
+ struct bpf_dtab_netdev *dev;
+ struct hlist_head *head;
+ struct hlist_node *next;
+
+ head = dev_map_index_hash(dtab, i);
+
+ hlist_for_each_entry_safe(dev, next, head, index_hlist) {
+ if (netdev != dev->dev)
+ continue;
+
+ dtab->items--;
+ hlist_del_rcu(&dev->index_hlist);
+ call_rcu(&dev->rcu, __dev_map_entry_free);
+ }
+ }
+ spin_unlock_irqrestore(&dtab->index_lock, flags);
+}
+
static int dev_map_notification(struct notifier_block *notifier,
ulong event, void *ptr)
{
@@ -735,6 +761,11 @@ static int dev_map_notification(struct notifier_block *notifier,
*/
rcu_read_lock();
list_for_each_entry_rcu(dtab, &dev_map_list, list) {
+ if (dtab->map.map_type == BPF_MAP_TYPE_DEVMAP_HASH) {
+ dev_map_hash_remove_netdev(dtab, netdev);
+ continue;
+ }
+
for (i = 0; i < dtab->map.max_entries; i++) {
struct bpf_dtab_netdev *dev, *odev;
--
2.23.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type
2019-10-19 11:19 [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
@ 2019-10-21 15:56 ` Martin Lau
2019-10-21 22:50 ` Alexei Starovoitov
1 sibling, 0 replies; 3+ messages in thread
From: Martin Lau @ 2019-10-21 15:56 UTC (permalink / raw)
To: Toke Høiland-Jørgensen
Cc: daniel, Alexei Starovoitov, bpf, netdev, Tetsuo Handa
On Sat, Oct 19, 2019 at 01:19:31PM +0200, Toke Høiland-Jørgensen wrote:
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
Acked-by: Martin KaFai Lau <kafai@fb.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type
2019-10-19 11:19 [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
2019-10-21 15:56 ` Martin Lau
@ 2019-10-21 22:50 ` Alexei Starovoitov
1 sibling, 0 replies; 3+ messages in thread
From: Alexei Starovoitov @ 2019-10-21 22:50 UTC (permalink / raw)
To: Toke Høiland-Jørgensen
Cc: Daniel Borkmann, Alexei Starovoitov, bpf, Network Development,
Martin KaFai Lau, Tetsuo Handa
On Sat, Oct 19, 2019 at 4:19 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote:
>
> It seems I forgot to add handling of devmap_hash type maps to the device
> unregister hook for devmaps. This omission causes devices to not be
> properly released, which causes hangs.
>
> Fix this by adding the missing handler.
>
> Fixes: 6f9d451ab1a3 ("xdp: Add devmap_hash map type for looking up devices by hashed index")
> Reported-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com>
Applied. Thanks!
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-10-21 22:50 UTC | newest]
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2019-10-19 11:19 [PATCH bpf v4] xdp: Handle device unregister for devmap_hash map type Toke Høiland-Jørgensen
2019-10-21 15:56 ` Martin Lau
2019-10-21 22:50 ` Alexei Starovoitov
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