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 42C673E51D4 for ; Mon, 31 Aug 2026 12:27:03 +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=1788179224; cv=none; b=QvGlXtyULkzqObRGTt8BpMsMeW1kBgyd6PXFRMHCieFqrttrH/4I8w7j13dseErYSLD4yM1VmnW6RBxGWUMo0lmFQdFk/VZygd6tOrl3wf9WgHzwijTnWeyoIrwU7pxuw9B9SmU39dF9IKlKmFDVdNsZ1AUJkKrjP0SrS8cL/SM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788179224; c=relaxed/simple; bh=dpaLiWD2kZ2b94nDDv0FUpQC9YtMDicn/mfkg0QF/7I=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=Dr60guPKLevfoPADNk9x75ImAm0ETIn0eJcxsfvB+LLM13hLtU7qb+nRhw5WHYx6SWvhRJ1wbk4WNs96rP8htz0u9bFH0Ta359IS+HEyhOzm3rH6s2i7FodnTrhSe7/IdmgbRCUK20EPTG8CbaUGcKmNw/l/YDxitejilIWA7s0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=PfnaE3gp; 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="PfnaE3gp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9F2931F000E9; Mon, 31 Aug 2026 12:27:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788179223; bh=8fTceV9l147o22HX6Y5RoIkrPB6LGzfpAoVM/7q29hY=; h=Subject:To:Cc:From:Date; b=PfnaE3gp8vgJXb4IXvfQj8Ywy6KNm/GjKJk1UHjEO+QkOIZJaqfamzACY4JvZib/b ZEq+vgr/Hyz+9gQkuH5YALPa7MZTwG9IeUdAiLsBeB4uepp+jtxPhIgWkUs/+ti06c pVDeJSUrX8fLRmx+ZbQtyBuMkYTVsW+dGsPLnYFc= Subject: FAILED: patch "[PATCH] gtp: serialize PDP context updates" failed to apply to 6.6-stable tree To: a0yami@mailbox.org,kuba@kernel.org Cc: From: Date: Mon, 31 Aug 2026 14:26:59 +0200 Message-ID: <2026083159-appetizer-scanning-c174@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.6-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y git checkout FETCH_HEAD git cherry-pick -x 498386b6d402737db1e2eeed4c385acbf0ef9e34 # git commit -s git send-email --to '' --in-reply-to '2026083159-appetizer-scanning-c174@gregkh' --subject-prefix 'PATCH 6.6.y' 'HEAD^..' Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 498386b6d402737db1e2eeed4c385acbf0ef9e34 Mon Sep 17 00:00:00 2001 From: Qing Ming Date: Tue, 18 Aug 2026 23:00:00 +0800 Subject: [PATCH] gtp: serialize PDP context updates 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 diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c index 9a12cc53da00..2f6e77cce385 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 @@ -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(struct gtp_dev *gtp, u64 tid, u16 family) 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(struct gtp_dev *gtp, u32 tid, u16 family) 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(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.s_addr == ms_addr) return pdp; @@ -220,7 +225,8 @@ static struct pdp_ctx *ipv6_pdp_find(struct gtp_dev *gtp, 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_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); @@ -2053,6 +2061,7 @@ 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); @@ -2060,6 +2069,7 @@ 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(); @@ -2134,6 +2144,8 @@ 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); @@ -2154,6 +2166,7 @@ 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; }