From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793210492; b=rIgBJfJs4hyCWphokGQXb+IvFngCBPJEeffA/R59XivS5EVbURMRISajS+bbrAz4+QMY E+M/JeasDahV0nennGU6lQz3ywjOh1/MpZahm3L725NCRWLBZwndNzaJFaTRx9RNQZzRv CnMtbNduCY43p4puySSt0JnOL1irQ/SSOjKONRdHcfwBeHp7+0COa7ZQcZtei6hG3V5lE lwQ4lTEPFOdzt6jhN773fx1sdaziaDkcYmo8LG8Spbb7eQE5Ymxm4bGi+vbHIYmeQsUt+ Nhbd4jzeSSS+kgTnh6gR7/ZynIFEJR0TkvqKEe2dF2KR4pV3vnWDa/Q9l2cgmq+6/Tg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210492; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=bwQs8kCzMbhDNvEwQrWLknQCPY9Jg5/3YwxvNkNFeyY=; b=oedPqDZeXj8NizaK1cBm8/4fOpmGEGAO0Yb7k/awsn5w5WwoXSn2nSZpJxct6C/jg1hl ik4u/OJy9mzg3FcWL9KPevEaBehfWzbuvkoLCdfjj11/869xDl54sP24zBkqCRs0n8MZH fInt/QE2bXxCPQeUbDHykb/y2V6LWo4JTM2U62PhsaOlKZPYgEfgxtLa2oaDY0MK+2mWz dqybIFIAiW3nn6vFKykr7lPKmVQgzXgCrfr6TYXhzIOpFzqn5N318zHURqENa25kl2c1j DUAkMcHdPeYVUYhF9FI45w5peoopWAbh1fyOW4Mi9DLGHO+DTReWGMLzgRcBpflz5xg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="IOl/macP"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A25D606A31E; Wed, 28 Oct 2026 18:01:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=IOl/macP Received: by smtp.kernel.org (Postfix) with ESMTPSA id B75E61F01825; Wed, 28 Oct 2026 18:01:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210492; bh=bwQs8kCzMbhDNvEwQrWLknQCPY9Jg5/3YwxvNkNFeyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=IOl/macPRYny3PGFPhjhf6NbnnDVvClpFf1n5uc7XfOVRC5cCU62sEYEXXB0Tcdft UMz3ABEBNQA6ZmqmWWLb+Ah13giIT6J883jeddGdU7zX82QzsDvwtYjy2pw4suKB2o 6FewRCf1X7bDVg6tum5O2OSZRoqulaBvZNN11l1w= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qing Ming , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 046/571] gtp: serialize PDP context updates Date: Wed, 28 Oct 2026 17:53:13 +0100 Message-ID: <20261028170009.121333586@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028170008.009143722@linuxfoundation.org> References: <20261028170008.009143722@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Qing Ming [ Upstream commit 498386b6d402737db1e2eeed4c385acbf0ef9e34 ] 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 [ adapted the locking changes to the older IPv4-only PDP context API and omitted the absent IPv6 lookup hunk. ] Signed-off-by: Sasha Levin --- drivers/net/gtp.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 99927adcb37a8..d38def0f2d53e 100644 --- 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 @@ -82,6 +83,7 @@ struct gtp_net { }; static u32 gtp_h_initval; +static DEFINE_MUTEX(gtp_pdp_lock); static void pdp_context_delete(struct pdp_ctx *pctx); @@ -109,7 +111,8 @@ static struct pdp_ctx *gtp0_pdp_find(struct gtp_dev *gtp, u64 tid) 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->gtp_version == GTP_V0 && pdp->u.v0.tid == tid) return pdp; @@ -125,7 +128,8 @@ static struct pdp_ctx *gtp1_pdp_find(struct gtp_dev *gtp, u32 tid) 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->gtp_version == GTP_V1 && pdp->u.v1.i_tei == tid) return pdp; @@ -141,7 +145,8 @@ static struct pdp_ctx *ipv4_pdp_find(struct gtp_dev *gtp, __be32 ms_addr) 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_ip4.s_addr == ms_addr) return pdp; @@ -722,9 +727,11 @@ static void gtp_dellink(struct net_device *dev, struct list_head *head) 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); @@ -1112,6 +1119,7 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) goto out_unlock; } + mutex_lock(>p_pdp_lock); pctx = gtp_pdp_add(gtp, sk, info); if (IS_ERR(pctx)) { err = PTR_ERR(pctx); @@ -1119,6 +1127,7 @@ static int gtp_genl_new_pdp(struct sk_buff *skb, struct genl_info *info) gtp_tunnel_notify(pctx, GTP_CMD_NEWPDP, GFP_KERNEL); err = 0; } + mutex_unlock(>p_pdp_lock); out_unlock: rtnl_unlock(); @@ -1173,6 +1182,8 @@ static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info) 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); @@ -1193,6 +1204,7 @@ static int gtp_genl_del_pdp(struct sk_buff *skb, struct genl_info *info) out_unlock: rcu_read_unlock(); + mutex_unlock(>p_pdp_lock); return err; } -- 2.53.0