From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 8B61A29A31C; Mon, 23 Mar 2026 13:57:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274230; cv=none; b=GW5naufBBLk9PWekc6umoa/dv4+mySxcyu4vGNfGE/dPdiqL4hXkauL33g+7rQh+e1h7d6S4OWS/ShMyorZ6p0GiYZecjN2479SqSdUGw93iMUG5qrrRbX3Y5PBhF8GBXKKOqnTTLVfAvcFruu39742ieQh282kZBBdFpzAaMp0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774274230; c=relaxed/simple; bh=HtxYgt13SFolWX9a0UXOTJTe3QG+4TNqVe7bKlBWsBc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p4mpO2Q1EjBGytE8o5wwqKHJ9C3QNw4GvQUwbHuLGEqUHA09h7vTO1iUsrCo336YwMWSDR07bRFgsXbwlLYOlTW7ye2Ac+hv7q2cruM1QhDxEzWooLIKF4qTZynZO3wTH4YX0Y7EvfCmQJ67h2Y/9g+qcuggbDd7zQbI1ve60Kk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=oC/AVuFn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="oC/AVuFn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0D7A8C4CEF7; Mon, 23 Mar 2026 13:57:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1774274230; bh=HtxYgt13SFolWX9a0UXOTJTe3QG+4TNqVe7bKlBWsBc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=oC/AVuFn4hgzBpAUZZuDoLCe3Ff06nEEhFSO6ESjlZy7Zw8b5GWGHlwJ6RyBChe+q wZwKqNgKO37OpDzYp68q+IR8Ft6pWO/cfockp2JLSpuA2MGj+GIp1O/8WT/tfmc6dv 9g2PCyxYBnOwnvi8MYMyVS9L3pIDHCPYKolZrg3o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Xianrui Dong , Victor Nogueira , Jamal Hadi Salim , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.19 150/220] net/sched: teql: Fix double-free in teql_master_xmit Date: Mon, 23 Mar 2026 14:45:27 +0100 Message-ID: <20260323134509.323767315@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260323134504.575022936@linuxfoundation.org> References: <20260323134504.575022936@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jamal Hadi Salim [ Upstream commit 66360460cab63c248ca5b1070a01c0c29133b960 ] Whenever a TEQL devices has a lockless Qdisc as root, qdisc_reset should be called using the seq_lock to avoid racing with the datapath. Failure to do so may cause crashes like the following: [ 238.028993][ T318] BUG: KASAN: double-free in skb_release_data (net/core/skbuff.c:1139) [ 238.029328][ T318] Free of addr ffff88810c67ec00 by task poc_teql_uaf_ke/318 [ 238.029749][ T318] [ 238.029900][ T318] CPU: 3 UID: 0 PID: 318 Comm: poc_teql_ke Not tainted 7.0.0-rc3-00149-ge5b31d988a41 #704 PREEMPT(full) [ 238.029906][ T318] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 238.029910][ T318] Call Trace: [ 238.029913][ T318] [ 238.029916][ T318] dump_stack_lvl (lib/dump_stack.c:122) [ 238.029928][ T318] print_report (mm/kasan/report.c:379 mm/kasan/report.c:482) [ 238.029940][ T318] ? skb_release_data (net/core/skbuff.c:1139) [ 238.029944][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) ... [ 238.029957][ T318] ? skb_release_data (net/core/skbuff.c:1139) [ 238.029969][ T318] kasan_report_invalid_free (mm/kasan/report.c:221 mm/kasan/report.c:563) [ 238.029979][ T318] ? skb_release_data (net/core/skbuff.c:1139) [ 238.029989][ T318] check_slab_allocation (mm/kasan/common.c:231) [ 238.029995][ T318] kmem_cache_free (mm/slub.c:2637 (discriminator 1) mm/slub.c:6168 (discriminator 1) mm/slub.c:6298 (discriminator 1)) [ 238.030004][ T318] skb_release_data (net/core/skbuff.c:1139) ... [ 238.030025][ T318] sk_skb_reason_drop (net/core/skbuff.c:1256) [ 238.030032][ T318] pfifo_fast_reset (./include/linux/ptr_ring.h:171 ./include/linux/ptr_ring.h:309 ./include/linux/skb_array.h:98 net/sched/sch_generic.c:827) [ 238.030039][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) ... [ 238.030054][ T318] qdisc_reset (net/sched/sch_generic.c:1034) [ 238.030062][ T318] teql_destroy (./include/linux/spinlock.h:395 net/sched/sch_teql.c:157) [ 238.030071][ T318] __qdisc_destroy (./include/net/pkt_sched.h:328 net/sched/sch_generic.c:1077) [ 238.030077][ T318] qdisc_graft (net/sched/sch_api.c:1062 net/sched/sch_api.c:1053 net/sched/sch_api.c:1159) [ 238.030089][ T318] ? __pfx_qdisc_graft (net/sched/sch_api.c:1091) [ 238.030095][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 238.030102][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 238.030106][ T318] ? srso_alias_return_thunk (arch/x86/lib/retpoline.S:221) [ 238.030114][ T318] tc_get_qdisc (net/sched/sch_api.c:1529 net/sched/sch_api.c:1556) ... [ 238.072958][ T318] Allocated by task 303 on cpu 5 at 238.026275s: [ 238.073392][ T318] kasan_save_stack (mm/kasan/common.c:58) [ 238.073884][ T318] kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5)) [ 238.074230][ T318] __kasan_slab_alloc (mm/kasan/common.c:369) [ 238.074578][ T318] kmem_cache_alloc_node_noprof (./include/linux/kasan.h:253 mm/slub.c:4542 mm/slub.c:4869 mm/slub.c:4921) [ 238.076091][ T318] kmalloc_reserve (net/core/skbuff.c:616 (discriminator 107)) [ 238.076450][ T318] __alloc_skb (net/core/skbuff.c:713) [ 238.076834][ T318] alloc_skb_with_frags (./include/linux/skbuff.h:1383 net/core/skbuff.c:6763) [ 238.077178][ T318] sock_alloc_send_pskb (net/core/sock.c:2997) [ 238.077520][ T318] packet_sendmsg (net/packet/af_packet.c:2926 net/packet/af_packet.c:3019 net/packet/af_packet.c:3108) [ 238.081469][ T318] [ 238.081870][ T318] Freed by task 299 on cpu 1 at 238.028496s: [ 238.082761][ T318] kasan_save_stack (mm/kasan/common.c:58) [ 238.083481][ T318] kasan_save_track (mm/kasan/common.c:64 (discriminator 5) mm/kasan/common.c:79 (discriminator 5)) [ 238.085348][ T318] kasan_save_free_info (mm/kasan/generic.c:587 (discriminator 1)) [ 238.085900][ T318] __kasan_slab_free (mm/kasan/common.c:287) [ 238.086439][ T318] kmem_cache_free (mm/slub.c:6168 (discriminator 3) mm/slub.c:6298 (discriminator 3)) [ 238.087007][ T318] skb_release_data (net/core/skbuff.c:1139) [ 238.087491][ T318] consume_skb (net/core/skbuff.c:1451) [ 238.087757][ T318] teql_master_xmit (net/sched/sch_teql.c:358) [ 238.088116][ T318] dev_hard_start_xmit (./include/linux/netdevice.h:5324 ./include/linux/netdevice.h:5333 net/core/dev.c:3871 net/core/dev.c:3887) [ 238.088468][ T318] sch_direct_xmit (net/sched/sch_generic.c:347) [ 238.088820][ T318] __qdisc_run (net/sched/sch_generic.c:420 (discriminator 1)) [ 238.089166][ T318] __dev_queue_xmit (./include/net/sch_generic.h:229 ./include/net/pkt_sched.h:121 ./include/net/pkt_sched.h:117 net/core/dev.c:4196 net/core/dev.c:4802) Workflow to reproduce: 1. Initialize a TEQL topology (dummy0 and ifb0 as slaves, teql0 up). 2. Start multiple sender workers continuously transmitting packets through teql0 to drive teql_master_xmit(). 3. In parallel, repeatedly delete and re-add the root qdisc on dummy0 and ifb0 via RTNETLINK, forcing frequent teardown and reset activity (teql_destroy() / qdisc_reset()). 4. After running both workloads concurrently for several iterations, KASAN reports slab-use-after-free or double-free in the skb free path. Fix this by moving dev_reset_queue to sch_generic.h and calling it, instead of qdisc_reset, in teql_destroy since it handles both the lock and lockless cases correctly for root qdiscs. Fixes: 96009c7d500e ("sched: replace __QDISC_STATE_RUNNING bit with a spin lock") Reported-by: Xianrui Dong Tested-by: Xianrui Dong Co-developed-by: Victor Nogueira Signed-off-by: Victor Nogueira Signed-off-by: Jamal Hadi Salim Link: https://patch.msgid.link/20260315155422.147256-1-jhs@mojatatu.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- include/net/sch_generic.h | 28 ++++++++++++++++++++++++++++ net/sched/sch_generic.c | 27 --------------------------- net/sched/sch_teql.c | 7 ++----- 3 files changed, 30 insertions(+), 32 deletions(-) diff --git a/include/net/sch_generic.h b/include/net/sch_generic.h index d5d55cb21686d..cafb266a0b80d 100644 --- a/include/net/sch_generic.h +++ b/include/net/sch_generic.h @@ -716,6 +716,34 @@ void qdisc_destroy(struct Qdisc *qdisc); void qdisc_put(struct Qdisc *qdisc); void qdisc_put_unlocked(struct Qdisc *qdisc); void qdisc_tree_reduce_backlog(struct Qdisc *qdisc, int n, int len); + +static inline void dev_reset_queue(struct net_device *dev, + struct netdev_queue *dev_queue, + void *_unused) +{ + struct Qdisc *qdisc; + bool nolock; + + qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); + if (!qdisc) + return; + + nolock = qdisc->flags & TCQ_F_NOLOCK; + + if (nolock) + spin_lock_bh(&qdisc->seqlock); + spin_lock_bh(qdisc_lock(qdisc)); + + qdisc_reset(qdisc); + + spin_unlock_bh(qdisc_lock(qdisc)); + if (nolock) { + clear_bit(__QDISC_STATE_MISSED, &qdisc->state); + clear_bit(__QDISC_STATE_DRAINING, &qdisc->state); + spin_unlock_bh(&qdisc->seqlock); + } +} + #ifdef CONFIG_NET_SCHED int qdisc_offload_dump_helper(struct Qdisc *q, enum tc_setup_type type, void *type_data); diff --git a/net/sched/sch_generic.c b/net/sched/sch_generic.c index 852e603c17551..8b07d194c4c35 100644 --- a/net/sched/sch_generic.c +++ b/net/sched/sch_generic.c @@ -1290,33 +1290,6 @@ static void dev_deactivate_queue(struct net_device *dev, } } -static void dev_reset_queue(struct net_device *dev, - struct netdev_queue *dev_queue, - void *_unused) -{ - struct Qdisc *qdisc; - bool nolock; - - qdisc = rtnl_dereference(dev_queue->qdisc_sleeping); - if (!qdisc) - return; - - nolock = qdisc->flags & TCQ_F_NOLOCK; - - if (nolock) - spin_lock_bh(&qdisc->seqlock); - spin_lock_bh(qdisc_lock(qdisc)); - - qdisc_reset(qdisc); - - spin_unlock_bh(qdisc_lock(qdisc)); - if (nolock) { - clear_bit(__QDISC_STATE_MISSED, &qdisc->state); - clear_bit(__QDISC_STATE_DRAINING, &qdisc->state); - spin_unlock_bh(&qdisc->seqlock); - } -} - static bool some_qdisc_is_busy(struct net_device *dev) { unsigned int i; diff --git a/net/sched/sch_teql.c b/net/sched/sch_teql.c index 783300d8b0197..ec4039a201a2c 100644 --- a/net/sched/sch_teql.c +++ b/net/sched/sch_teql.c @@ -146,15 +146,12 @@ teql_destroy(struct Qdisc *sch) master->slaves = NEXT_SLAVE(q); if (q == master->slaves) { struct netdev_queue *txq; - spinlock_t *root_lock; txq = netdev_get_tx_queue(master->dev, 0); master->slaves = NULL; - root_lock = qdisc_root_sleeping_lock(rtnl_dereference(txq->qdisc)); - spin_lock_bh(root_lock); - qdisc_reset(rtnl_dereference(txq->qdisc)); - spin_unlock_bh(root_lock); + dev_reset_queue(master->dev, + txq, NULL); } } skb_queue_purge(&dat->q); -- 2.51.0