[PATCH 6.1] tls: rx: strp: don't use GFP_KERNEL in softirq context

[PATCH 6.1] tls: rx: strp: don't use GFP_KERNEL in softirq context

[Jakub Kicinski]

[ Upstream commit 74836ec828fe17b63f2006fdbf53311d691396bf ]

When receive buffer is small, or the TCP rx queue looks too
complicated to bother using it directly - we allocate a new
skb and copy data into it.

We already use sk->sk_allocation... but nothing actually
sets it to GFP_ATOMIC on the ->sk_data_ready() path.

Users of HW offload are far more likely to experience problems
due to scheduling while atomic. "Copy mode" is very rarely
triggered with SW crypto.

Fixes: 84c61fe1a75b ("tls: rx: do not use the standard strparser")
Tested-by: Shai Amiram <samiram@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---
 net/tls/tls_sw.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/net/tls/tls_sw.c b/net/tls/tls_sw.c
index 992092aeebad..3a08cf1258b5 100644
--- a/net/tls/tls_sw.c
+++ b/net/tls/tls_sw.c
@@ -2287,8 +2287,12 @@ static void tls_data_ready(struct sock *sk)
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_sw_context_rx *ctx = tls_sw_ctx_rx(tls_ctx);
 	struct sk_psock *psock;
+	gfp_t alloc_save;
 
+	alloc_save = sk->sk_allocation;
+	sk->sk_allocation = GFP_ATOMIC;
 	tls_strp_data_ready(&ctx->strp);
+	sk->sk_allocation = alloc_save;
 
 	psock = sk_psock_get(sk);
 	if (psock) {
-- 
2.34.1

Re: [PATCH 6.1] tls: rx: strp: don't use GFP_KERNEL in softirq context

[Greg KH]

On Mon, Jun 05, 2023 at 09:42:41PM -0700, Jakub Kicinski wrote:
> [ Upstream commit 74836ec828fe17b63f2006fdbf53311d691396bf ]
> 
> When receive buffer is small, or the TCP rx queue looks too
> complicated to bother using it directly - we allocate a new
> skb and copy data into it.
> 
> We already use sk->sk_allocation... but nothing actually
> sets it to GFP_ATOMIC on the ->sk_data_ready() path.
> 
> Users of HW offload are far more likely to experience problems
> due to scheduling while atomic. "Copy mode" is very rarely
> triggered with SW crypto.
> 
> Fixes: 84c61fe1a75b ("tls: rx: do not use the standard strparser")
> Tested-by: Shai Amiram <samiram@nvidia.com>
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
> Reviewed-by: Simon Horman <simon.horman@corigine.com>
> Signed-off-by: David S. Miller <davem@davemloft.net>
> ---
>  net/tls/tls_sw.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 

Now queued up, thanks.

greg k-h