4.19-stable review patch. If anyone has any objections, please let me know.
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From: J. Bruce Fields bfields@redhat.com
commit b7e5034cbecf5a65b7bfdc2b20a8378039577706 upstream.
James Pearson found that an NFS server stopped responding to UDP requests if started with more than 1017 threads.
sv_max_mesg is about 2^20, so that is probably where the calculation performed by
svc_sock_setbufsize(svsk->sk_sock, (serv->sv_nrthreads+3) * serv->sv_max_mesg, (serv->sv_nrthreads+3) * serv->sv_max_mesg);
starts to overflow an int.
Reported-by: James Pearson jcpearson@gmail.com Tested-by: James Pearson jcpearson@gmail.com Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields bfields@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/sunrpc/svcsock.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
--- a/net/sunrpc/svcsock.c +++ b/net/sunrpc/svcsock.c @@ -381,12 +381,16 @@ static int svc_partial_recvfrom(struct s /* * Set socket snd and rcv buffer lengths */ -static void svc_sock_setbufsize(struct socket *sock, unsigned int snd, - unsigned int rcv) +static void svc_sock_setbufsize(struct svc_sock *svsk, unsigned int nreqs) { + unsigned int max_mesg = svsk->sk_xprt.xpt_server->sv_max_mesg; + struct socket *sock = svsk->sk_sock; + + nreqs = min(nreqs, INT_MAX / 2 / max_mesg); + lock_sock(sock->sk); - sock->sk->sk_sndbuf = snd * 2; - sock->sk->sk_rcvbuf = rcv * 2; + sock->sk->sk_sndbuf = nreqs * max_mesg * 2; + sock->sk->sk_rcvbuf = nreqs * max_mesg * 2; sock->sk->sk_write_space(sock->sk); release_sock(sock->sk); } @@ -548,9 +552,7 @@ static int svc_udp_recvfrom(struct svc_r * provides an upper bound on the number of threads * which will access the socket. */ - svc_sock_setbufsize(svsk->sk_sock, - (serv->sv_nrthreads+3) * serv->sv_max_mesg, - (serv->sv_nrthreads+3) * serv->sv_max_mesg); + svc_sock_setbufsize(svsk, serv->sv_nrthreads + 3);
clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); skb = NULL; @@ -718,9 +720,7 @@ static void svc_udp_init(struct svc_sock * receive and respond to one request. * svc_udp_recvfrom will re-adjust if necessary */ - svc_sock_setbufsize(svsk->sk_sock, - 3 * svsk->sk_xprt.xpt_server->sv_max_mesg, - 3 * svsk->sk_xprt.xpt_server->sv_max_mesg); + svc_sock_setbufsize(svsk, 3);
/* data might have come in before data_ready set up */ set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);