Re: [PATCH bpf] bpf, sockmap: Fix bug that strp_done cannot be called

On 8/1/2023 11:55 AM, John Fastabend wrote:

Xu Kuohai wrote:

quoted

From: Xu Kuohai <redacted>

strp_done is only called when psock->progs.stream_parser is not NULL,
but stream_parser was set to NULL by sk_psock_stop_strp(), called
by sk_psock_drop() earlier. So, strp_done can never be called.

Introduce SK_PSOCK_RX_ENABLED to mark whether there is strp on psock.
Change the condition for calling strp_done from judging whether
stream_parser is set to judging whether this flag is set. This flag is
only set once when strp_init() succeeds, and will never be cleared later.

Fixes: c0d95d3380ee ("bpf, sockmap: Re-evaluate proto ops when psock is removed from sockmap")
Signed-off-by: Xu Kuohai <redacted>
---
  include/linux/skmsg.h |  1 +
  net/core/skmsg.c      | 10 ++++++++--
  2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 054d7911bfc9..959c5f4c4d19 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h

@@ -62,6 +62,7 @@ struct sk_psock_progs {
  
  enum sk_psock_state_bits {
  	SK_PSOCK_TX_ENABLED,
+	SK_PSOCK_RX_ENABLED,

small nit can be make this SK_PSOCK_RX_STRP_ENABLED? That way its
explicit what we are talking about here.

OK, I'll rename it, thanks.

Otherwise it looks good thanks nice catch.

quoted

  };
  
  struct sk_psock_link {

diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index a29508e1ff35..7c2764beeb04 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c

@@ -1120,13 +1120,19 @@ static void sk_psock_strp_data_ready(struct sock *sk)
  
  int sk_psock_init_strp(struct sock *sk, struct sk_psock *psock)
  {
+	int ret;
+
  	static const struct strp_callbacks cb = {
  		.rcv_msg	= sk_psock_strp_read,
  		.read_sock_done	= sk_psock_strp_read_done,
  		.parse_msg	= sk_psock_strp_parse,
  	};
  
-	return strp_init(&psock->strp, sk, &cb);
+	ret = strp_init(&psock->strp, sk, &cb);
+	if (!ret)
+		sk_psock_set_state(psock, SK_PSOCK_RX_ENABLED);
+
+	return ret;
  }
  
  void sk_psock_start_strp(struct sock *sk, struct sk_psock *psock)

@@ -1154,7 +1160,7 @@ void sk_psock_stop_strp(struct sock *sk, struct sk_psock *psock)
  static void sk_psock_done_strp(struct sk_psock *psock)
  {
  	/* Parser has been stopped */
-	if (psock->progs.stream_parser)
+	if (sk_psock_test_state(psock, SK_PSOCK_RX_ENABLED))
  		strp_done(&psock->strp);
  }
  #else

-- 
2.30.2