From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 99B7B4AC2A5; Mon, 31 Aug 2026 13:46:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184022; cv=none; b=KzP5eyX2G8Gyw33yAfIwhwGdJcW0zDwv8mm50vnmz70+rOF9M233LvR4EkHu6n9sJf5LUOzgBxWghWroez0lKSfi+2c7E72s+SMzt7sSGm/ScH1w/OwLHxmkUJdvESDvRvh408TJo3b0qfxIe5+3keTrhxhTm+0/PLwh45gIs9A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788184022; c=relaxed/simple; bh=RBWOnFxDb0XbMNAOLNb1rKMPkTzrruR7Edgkk9dSheI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Mh1cphzHTIht8AVtxgPqQXNqs7Nxdy+6R4wG8Bo+RJa5CI3uzB/6Znm1oXftRi1zpMRBj9OFtBxwtiPYbtR6vsNzErYMSpTqPDzmC9hEVrndhi1MwPFUGnPx0ikNSXKl/+5XQRpCWEFT5bBftbyjzzCFSMMwYB3H5lQy7Ee562U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=iTjWCZx6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="iTjWCZx6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E91AA1F00ACF; Mon, 31 Aug 2026 13:46:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788184019; bh=hzi2Xw5mjeo4/kINvmYAh+Xbv7aq28rUcO2XgiOymYA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iTjWCZx6DaPYiFTQHfgKEmS51yZMbQCrT9Ig/pqroD0ByXsa5lODZVmUSRYKucQt5 9peJ7tunyyMSOuKHLWTLXWAnRRu0d86tKlUctDMtpJnr7p6nLBu+R/Yj61ngjVMwdd xplkec81L333keeGW1QJ/gHG/KHTcYZYu+gKJlWc= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qing Ming , Jakub Kicinski Subject: [PATCH 6.18 46/83] gtp: serialize PDP context updates Date: Mon, 31 Aug 2026 15:34:22 +0200 Message-ID: <20260831133401.854594263@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260831133359.207714926@linuxfoundation.org> References: <20260831133359.207714926@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qing Ming commit 498386b6d402737db1e2eeed4c385acbf0ef9e34 upstream. PDP contexts can be deleted through GTP_CMD_DELPDP or while the GTP network device is being unregistered. The latter is serialized by RTNL, but the generic-netlink delete path only holds RCU. Running both paths concurrently can therefore make both paths delete the same PDP context. The issue was found through static analysis and reproduced on a KASAN-enabled kernel by a simple two-thread program racing GTP_CMD_DELPDP against RTM_DELLINK: Oops: general protection fault, probably for non-canonical address KASAN: maybe wild-memory-access in range [0xdead000000000120-0xdead000000000127] RIP: gtp_genl_del_pdp+0x1c1/0x420 [gtp] RBP: dead000000000122 The second deletion dereferenced the poisoned hlist pprev pointer. Serialize gtp_pdp_add(), gtp_genl_del_pdp(), and gtp_dellink() with a shared mutex. Keep the mutex held until the final use of a PDP context in the NEWPDP path, and keep the RCU read-side section around the complete PDP context use in the DELPDP path. Fixes: 459aa660eb1d ("gtp: add initial driver for datapath of GPRS Tunneling Protocol (GTP-U)") Cc: stable@vger.kernel.org Signed-off-by: Qing Ming Link: https://patch.msgid.link/20260818150000.7670-1-a0yami@mailbox.org Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/gtp.c | 21 +++++++++++++++++---- 1 file changed, 17 insertions(+), 4 deletions(-) --- a/drivers/net/gtp.c +++ b/drivers/net/gtp.c @@ -12,6 +12,7 @@ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include +#include #include #include #include @@ -108,6 +109,7 @@ struct gtp_net { }; static u32 gtp_h_initval; +static DEFINE_MUTEX(gtp_pdp_lock); static struct genl_family gtp_genl_family; @@ -151,7 +153,8 @@ static struct pdp_ctx *gtp0_pdp_find(str head = >p->tid_hash[gtp0_hashfn(tid) % gtp->hash_size]; - hlist_for_each_entry_rcu(pdp, head, hlist_tid) { + hlist_for_each_entry_rcu(pdp, head, hlist_tid, + lockdep_is_held(>p_pdp_lock)) { if (pdp->af == family && pdp->gtp_version == GTP_V0 && pdp->u.v0.tid == tid) @@ -168,7 +171,8 @@ static struct pdp_ctx *gtp1_pdp_find(str head = >p->tid_hash[gtp1u_hashfn(tid) % gtp->hash_size]; - hlist_for_each_entry_rcu(pdp, head, hlist_tid) { + hlist_for_each_entry_rcu(pdp, head, hlist_tid, + lockdep_is_held(>p_pdp_lock)) { if (pdp->af == family && pdp->gtp_version == GTP_V1 && pdp->u.v1.i_tei == tid) @@ -185,7 +189,8 @@ static struct pdp_ctx *ipv4_pdp_find(str head = >p->addr_hash[ipv4_hashfn(ms_addr) % gtp->hash_size]; - hlist_for_each_entry_rcu(pdp, head, hlist_addr) { + hlist_for_each_entry_rcu(pdp, head, hlist_addr, + lockdep_is_held(>p_pdp_lock)) { if (pdp->af == AF_INET && pdp->ms.addr.s_addr == ms_addr) return pdp; @@ -220,7 +225,8 @@ static struct pdp_ctx *ipv6_pdp_find(str head = >p->addr_hash[ipv6_hashfn(ms_addr) % gtp->hash_size]; - hlist_for_each_entry_rcu(pdp, head, hlist_addr) { + hlist_for_each_entry_rcu(pdp, head, hlist_addr, + lockdep_is_held(>p_pdp_lock)) { if (pdp->af == AF_INET6 && ipv6_pdp_addr_equal(&pdp->ms.addr6, ms_addr)) return pdp; @@ -1555,9 +1561,11 @@ static void gtp_dellink(struct net_devic struct pdp_ctx *pctx; int i; + mutex_lock(>p_pdp_lock); for (i = 0; i < gtp->hash_size; i++) hlist_for_each_entry_safe(pctx, next, >p->tid_hash[i], hlist_tid) pdp_context_delete(pctx); + mutex_unlock(>p_pdp_lock); list_del(>p->list); unregister_netdevice_queue(dev, head); @@ -2053,6 +2061,7 @@ static int gtp_genl_new_pdp(struct sk_bu goto out_unlock; } + mutex_lock(>p_pdp_lock); pctx = gtp_pdp_add(gtp, sk, info); if (IS_ERR(pctx)) { err = PTR_ERR(pctx); @@ -2060,6 +2069,7 @@ static int gtp_genl_new_pdp(struct sk_bu gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL); err = 0; } + mutex_unlock(>p_pdp_lock); out_unlock: rtnl_unlock(); @@ -2134,6 +2144,8 @@ static int gtp_genl_del_pdp(struct sk_bu if (!info->attrs[GTPA_VERSION]) return -EINVAL; + mutex_lock(>p_pdp_lock); + rcu_read_lock(); pctx = gtp_find_pdp(sock_net(skb->sk), info->attrs); @@ -2154,6 +2166,7 @@ static int gtp_genl_del_pdp(struct sk_bu out_unlock: rcu_read_unlock(); + mutex_unlock(>p_pdp_lock); return err; }