diff options
| author | Paolo Abeni | 2021-03-30 18:43:54 +0200 |
|---|---|---|
| committer | David S. Miller | 2021-03-30 13:57:28 -0700 |
| commit | 9adc89af724f12a03b47099cd943ed54e877cd59 (patch) | |
| tree | 6bf5372364c7c76a17132f6df8b55ad2b1afdd9d | |
| parent | ae81feb7338c89cee4e6aa0424bdab2ce2b52da2 (diff) | |
net: let skb_orphan_partial wake-up waiters.
Currently the mentioned helper can end-up freeing the socket wmem
without waking-up any processes waiting for more write memory.
If the partially orphaned skb is attached to an UDP (or raw) socket,
the lack of wake-up can hang the user-space.
Even for TCP sockets not calling the sk destructor could have bad
effects on TSQ.
Address the issue using skb_orphan to release the sk wmem before
setting the new sock_efree destructor. Additionally bundle the
whole ownership update in a new helper, so that later other
potential users could avoid duplicate code.
v1 -> v2:
- use skb_orphan() instead of sort of open coding it (Eric)
- provide an helper for the ownership change (Eric)
Fixes: f6ba8d33cfbb ("netem: fix skb_orphan_partial()")
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | include/net/sock.h | 9 | ||||
| -rw-r--r-- | net/core/sock.c | 12 |
2 files changed, 12 insertions, 9 deletions
diff --git a/include/net/sock.h b/include/net/sock.h index 0b6266fd6bf6..3e3a5da2ce5a 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -2221,6 +2221,15 @@ static inline void skb_set_owner_r(struct sk_buff *skb, struct sock *sk) sk_mem_charge(sk, skb->truesize); } +static inline void skb_set_owner_sk_safe(struct sk_buff *skb, struct sock *sk) +{ + if (sk && refcount_inc_not_zero(&sk->sk_refcnt)) { + skb_orphan(skb); + skb->destructor = sock_efree; + skb->sk = sk; + } +} + void sk_reset_timer(struct sock *sk, struct timer_list *timer, unsigned long expires); diff --git a/net/core/sock.c b/net/core/sock.c index cc31b601ae10..5ec90f99e102 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2132,16 +2132,10 @@ void skb_orphan_partial(struct sk_buff *skb) if (skb_is_tcp_pure_ack(skb)) return; - if (can_skb_orphan_partial(skb)) { - struct sock *sk = skb->sk; - - if (refcount_inc_not_zero(&sk->sk_refcnt)) { - WARN_ON(refcount_sub_and_test(skb->truesize, &sk->sk_wmem_alloc)); - skb->destructor = sock_efree; - } - } else { + if (can_skb_orphan_partial(skb)) + skb_set_owner_sk_safe(skb, skb->sk); + else skb_orphan(skb); - } } EXPORT_SYMBOL(skb_orphan_partial); |