From patchwork Tue Jul 2 15:23:13 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Taehee Yoo X-Patchwork-Id: 1126308 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="MLSKKna/"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45dSgH3VL4z9s00 for ; Wed, 3 Jul 2019 01:23:23 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726966AbfGBPXW (ORCPT ); Tue, 2 Jul 2019 11:23:22 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:38421 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726457AbfGBPXV (ORCPT ); Tue, 2 Jul 2019 11:23:21 -0400 Received: by mail-pl1-f195.google.com with SMTP id 9so553256ple.5 for ; Tue, 02 Jul 2019 08:23:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=CU7BGsZXNgazwEEiVe1gYY76OcBMUw+lUvNAfAOPgNY=; b=MLSKKna/xrK1VaVXFuvoDbVuBTMAy6NOIW2/YQTnHtLkwYhK0Fhr4AdqXiE0HkyVpB IvDEK5S+zlwne29XdSK5NHuukYf7E1CSZKKA9n0Fztpv46c8vHmEXndU4/gDYuodFhX2 Xa1sfiFbQWlJfprNemaZeMfDtof8T2F0tyxMtSmHyUpwSNx/I9sVGzOoIs4ZH75/VAVl GNH4nA5GjLlmDKjUjdaEvtmEx8CDawZucoA6Jtqyfxl8xRcgynTx3QDzWXnm5B9EDgEN vhGwLYhYEmP0bY7MR3v0aaY41rrHc/DBGMVBlpY8/YHBWNPg+SgPpmqFdGwLOI/AcxJj UMRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=CU7BGsZXNgazwEEiVe1gYY76OcBMUw+lUvNAfAOPgNY=; b=h+4dZ/344upgbP33KJnhGbI8RBHBsNrdjwBTW+9zHsqAI4hU6Dk/yFkvAK6vILZqu/ 33O0D8kdA6fN+TnsLUjlWCcn6DKU/XlxwHjOLO848BOgIAgz6QiMcXGfeNMUO0OCu6At HkexzRpFD5kXTV1v8E8gDHheKItbTbCMzYQ0rd/20Wa/AH+LdKyKAqoQGgEmbJCL2slu 0YIegKcZbzCkkAnz2bO163EaUnUfrrFaom48cmHsY+t6eMW6zlbz2rqk7RIQVlUmPqr8 pGkDKHmrJTxf0JHdtu4GAvnGnoO5s3GibN8LTXVCoyrgDTA5k7Xsp3JoMdM3tw9nz9vg KhaA== X-Gm-Message-State: APjAAAX1jn1OeWsJVPlJb4baqI5WAD8jQgwyPOAuKcR6tEYs4WdmQEkd iBShoAaLpnjof/CrWzEab+q1GwC+UNY= X-Google-Smtp-Source: APXvYqwtPnEfrC5Nq6Gt1QCf9xYk9SaYQGkcfaXa03gBpwwIWsMtqrqnd0JjMn+TC2zxOBbtZtyiZw== X-Received: by 2002:a17:902:e65:: with SMTP id 92mr34373719plw.13.1562081000553; Tue, 02 Jul 2019 08:23:20 -0700 (PDT) Received: from ap-To-be-filled-by-O-E-M.8.8.8.8 ([14.33.120.60]) by smtp.gmail.com with ESMTPSA id v3sm13882706pfm.188.2019.07.02.08.23.18 (version=TLS1_3 cipher=AEAD-AES256-GCM-SHA384 bits=256/256); Tue, 02 Jul 2019 08:23:19 -0700 (PDT) From: Taehee Yoo To: davem@davemloft.net, pablo@netfilter.org, laforge@gnumonks.org, osmocom-net-gprs@lists.osmocom.org, netdev@vger.kernel.org Cc: ap420073@gmail.com Subject: [PATCH net 4/6] gtp: fix Illegal context switch in RCU read-side critical section. Date: Wed, 3 Jul 2019 00:23:13 +0900 Message-Id: <20190702152313.22970-1-ap420073@gmail.com> X-Mailer: git-send-email 2.17.1 Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org ipv4_pdp_add() is called in RCU read-side critical section. So GFP_KERNEL should not be used in the function. This patch make ipv4_pdp_add() to use GFP_ATOMIC instead of GFP_KERNEL. Test commands: gtp-link add gtp1 & gtp-tunnel add gtp1 v1 100 200 1.1.1.1 2.2.2.2 Splat looks like: [ 130.618881] ============================= [ 130.626382] WARNING: suspicious RCU usage [ 130.626994] 5.2.0-rc6+ #50 Not tainted [ 130.627622] ----------------------------- [ 130.628223] ./include/linux/rcupdate.h:266 Illegal context switch in RCU read-side critical section! [ 130.629684] [ 130.629684] other info that might help us debug this: [ 130.629684] [ 130.631022] [ 130.631022] rcu_scheduler_active = 2, debug_locks = 1 [ 130.632136] 4 locks held by gtp-tunnel/1025: [ 130.632925] #0: 000000002b93c8b7 (cb_lock){++++}, at: genl_rcv+0x15/0x40 [ 130.634159] #1: 00000000f17bc999 (genl_mutex){+.+.}, at: genl_rcv_msg+0xfb/0x130 [ 130.635487] #2: 00000000c644ed8e (rtnl_mutex){+.+.}, at: gtp_genl_new_pdp+0x18c/0x1150 [gtp] [ 130.636936] #3: 0000000007a1cde7 (rcu_read_lock){....}, at: gtp_genl_new_pdp+0x187/0x1150 [gtp] [ 130.638348] [ 130.638348] stack backtrace: [ 130.639062] CPU: 1 PID: 1025 Comm: gtp-tunnel Not tainted 5.2.0-rc6+ #50 [ 130.641318] Call Trace: [ 130.641707] dump_stack+0x7c/0xbb [ 130.642252] ___might_sleep+0x2c0/0x3b0 [ 130.642862] kmem_cache_alloc_trace+0x1cd/0x2b0 [ 130.643591] gtp_genl_new_pdp+0x6c5/0x1150 [gtp] [ 130.644371] genl_family_rcv_msg+0x63a/0x1030 [ 130.645074] ? mutex_lock_io_nested+0x1090/0x1090 [ 130.645845] ? genl_unregister_family+0x630/0x630 [ 130.646592] ? debug_show_all_locks+0x2d0/0x2d0 [ 130.647293] ? check_flags.part.40+0x440/0x440 [ 130.648099] genl_rcv_msg+0xa3/0x130 [ ... ] Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Signed-off-by: Taehee Yoo --- drivers/net/gtp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 92ef777a757f..52f35cbeb1dc 100644 --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -959,7 +959,7 @@ static int ipv4_pdp_add(struct gtp_dev *gtp, struct sock *sk, } - pctx = kmalloc(sizeof(struct pdp_ctx), GFP_KERNEL); + pctx = kmalloc(sizeof(*pctx), GFP_ATOMIC); if (pctx == NULL) return -ENOMEM;