Re: [PATCH 3.18 010/145] sctp: avoid BUG_ON on sctp_wait_for_sndbuf

[Marcelo Ricardo Leitner]

Em 16-04-2017 07:48, Greg Kroah-Hartman escreveu:
> 3.18-stable review patch.  If anyone has any objections, please let me know.
>
> ------------------
>
> From: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
>
>
> [ Upstream commit 2dcab598484185dea7ec22219c76dcdd59e3cb90 ]


Hi Greg. Are you also including dfcb9f4f99f1 ("sctp: deny peeloff 
operation on asocs with threads sleeping on it")
It's a follow-up fix for this one, would be good to have it too.

> Alexander Popov reported that an application may trigger a BUG_ON in
> sctp_wait_for_sndbuf if the socket tx buffer is full, a thread is
> waiting on it to queue more data and meanwhile another thread peels off
> the association being used by the first thread.
>
> This patch replaces the BUG_ON call with a proper error handling. It
> will return -EPIPE to the original sendmsg call, similarly to what would
> have been done if the association wasn't found in the first place.
>
> Acked-by: Alexander Popov <alex.popov@xxxxxxxxx>
> Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
> Reviewed-by: Xin Long <lucien.xin@xxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
> ---
>   net/sctp/socket.c |    3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> --- a/net/sctp/socket.c
> +++ b/net/sctp/socket.c
> @@ -6962,7 +6962,8 @@ static int sctp_wait_for_sndbuf(struct s
>   		 */
>   		release_sock(sk);
>   		current_timeo = schedule_timeout(current_timeo);
> -		BUG_ON(sk != asoc->base.sk);
> +		if (sk != asoc->base.sk)
> +			goto do_error;
>   		lock_sock(sk);
>   
>   		*timeo_p = current_timeo;