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| author | Jakub Kicinski <jakub.kicinski@netronome.com> | 2019-04-17 10:51:19 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-04-18 16:51:03 -0700 |
| commit | 9188d5ca454fd665145904267e726e9e8d122f5c (patch) | |
| tree | 5ae8e056f8215559af87108a39e46d203876ac0e /net/tls/tls_device_fallback.c | |
| parent | e0c1d14a1a3211dccf0540a6703ffbd5d2a75bdb (diff) | |
| download | linux-9188d5ca454fd665145904267e726e9e8d122f5c.tar.bz2 | |
net/tls: fix refcount adjustment in fallback
Unlike atomic_add(), refcount_add() does not deal well
with a negative argument. TLS fallback code reallocates
the skb and is very likely to shrink the truesize, leading to:
[ 189.513254] WARNING: CPU: 5 PID: 0 at lib/refcount.c:81 refcount_add_not_zero_checked+0x15c/0x180
Call Trace:
refcount_add_checked+0x6/0x40
tls_enc_skb+0xb93/0x13e0 [tls]
Once wmem_allocated count saturates the application can no longer
send data on the socket. This is similar to Eric's fixes for GSO,
TCP:
commit 7ec318feeed1 ("tcp: gso: avoid refcount_t warning from tcp_gso_segment()")
and UDP:
commit 575b65bc5bff ("udp: avoid refcount_t saturation in __udp_gso_segment()").
Unlike the GSO case, for TLS fallback it's likely that the skb has
shrunk, so the "likely" annotation is the other way around (likely
branch being "sub").
Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: John Hurley <john.hurley@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tls/tls_device_fallback.c')
| -rw-r--r-- | net/tls/tls_device_fallback.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/net/tls/tls_device_fallback.c b/net/tls/tls_device_fallback.c index 54c3a758f2a7..a3ebd4b02714 100644 --- a/net/tls/tls_device_fallback.c +++ b/net/tls/tls_device_fallback.c @@ -194,6 +194,9 @@ static void update_chksum(struct sk_buff *skb, int headln) static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln) { + struct sock *sk = skb->sk; + int delta; + skb_copy_header(nskb, skb); skb_put(nskb, skb->len); @@ -201,11 +204,15 @@ static void complete_skb(struct sk_buff *nskb, struct sk_buff *skb, int headln) update_chksum(nskb, headln); nskb->destructor = skb->destructor; - nskb->sk = skb->sk; + nskb->sk = sk; skb->destructor = NULL; skb->sk = NULL; - refcount_add(nskb->truesize - skb->truesize, - &nskb->sk->sk_wmem_alloc); + + delta = nskb->truesize - skb->truesize; + if (likely(delta < 0)) + WARN_ON_ONCE(refcount_sub_and_test(-delta, &sk->sk_wmem_alloc)); + else if (delta) + refcount_add(delta, &sk->sk_wmem_alloc); } /* This function may be called after the user socket is already |