Return-Path: linux-nfs-owner@vger.kernel.org Received: from mail.tpi.com ([70.99.223.143]:4932 "EHLO mail.tpi.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750921Ab3CJPjt (ORCPT ); Sun, 10 Mar 2013 11:39:49 -0400 From: Tim Gardner To: linux-kernel@vger.kernel.org Cc: Tim Gardner , Trond Myklebust , "J. Bruce Fields" , "David S. Miller" , Tom Tucker , Haggai Eran , Or Gerlitz , Shani Michaeli , linux-nfs@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH linux-next] SUNRPC: rpcrdma_register_default_external: Dynamically allocate ib_phys_buf Date: Sun, 10 Mar 2013 09:39:13 -0600 Message-Id: <1362929953-63785-1-git-send-email-tim.gardner@canonical.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: rpcrdma_register_default_external() is several frames into the call stack which goes deeper yet. You run the risk of stack corruption by declaring such a large automatic variable, so dynamically allocate the array of 'struct ib_phys_buf' objects in order to silence the frame-larger-than warning. net/sunrpc/xprtrdma/verbs.c: In function 'rpcrdma_register_default_external': net/sunrpc/xprtrdma/verbs.c:1774:1: warning: the frame size of 1056 bytes is larger than 1024 bytes [-Wframe-larger-than=] gcc version 4.6.3 Cc: Trond Myklebust Cc: "J. Bruce Fields" Cc: "David S. Miller" Cc: Tom Tucker Cc: Haggai Eran Cc: Or Gerlitz Cc: Shani Michaeli Cc: linux-nfs@vger.kernel.org Cc: netdev@vger.kernel.org Signed-off-by: Tim Gardner --- net/sunrpc/xprtrdma/verbs.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/net/sunrpc/xprtrdma/verbs.c b/net/sunrpc/xprtrdma/verbs.c index 93726560..0916467 100644 --- a/net/sunrpc/xprtrdma/verbs.c +++ b/net/sunrpc/xprtrdma/verbs.c @@ -1736,9 +1736,13 @@ rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg, int mem_priv = (writing ? IB_ACCESS_REMOTE_WRITE : IB_ACCESS_REMOTE_READ); struct rpcrdma_mr_seg *seg1 = seg; - struct ib_phys_buf ipb[RPCRDMA_MAX_DATA_SEGS]; + struct ib_phys_buf *ipb; int len, i, rc = 0; + ipb = kmalloc(sizeof(*ipb) * RPCRDMA_MAX_DATA_SEGS, GFP_KERNEL); + if (!ipb) + return -ENOMEM; + if (*nsegs > RPCRDMA_MAX_DATA_SEGS) *nsegs = RPCRDMA_MAX_DATA_SEGS; for (len = 0, i = 0; i < *nsegs;) { @@ -1770,6 +1774,7 @@ rpcrdma_register_default_external(struct rpcrdma_mr_seg *seg, seg1->mr_len = len; } *nsegs = i; + kfree(ipb); return rc; } -- 1.7.9.5