From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from zg8tmtyylji0my4xnjeumjiw.icoremail.net (zg8tmtyylji0my4xnjeumjiw.icoremail.net [162.243.161.220]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 167492AD36 for ; Mon, 12 Oct 2026 01:07:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.243.161.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791767266; cv=none; b=jcFT42NsjjNlOGWGebij7AfX60oN1blPQ5szl+cmupYE0+Q4dijrfQwRgRsNz70crV8anRpwrWgi+17vOtMRx0L5Jr/X8uAk/t7xP0BUbNyRSS36qmFglmdlNdxDSmMxdvGM1Jhx4xan9xABSsQadzI2nPbtYhsMFFW9fji1X+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791767266; c=relaxed/simple; bh=ju5xrs8Z0YxAp95h4sVSMEQZgroTsDMTQOYN6n/5chY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ljNDHgO5gQ10oiexUe8XpWwFR8tUzUMb8qXjm2F+avjBCBu9ysPuL9tSa1v6ehWVrpGsGmio4Oe7WVG282kLCfUnaVd6BSvRHuzrkjrmD2cb8GyxznaFnDVUeGtoxd2HPixs5RCBuFwIWRsks7WgnpLB/7IDE/D5mE6oUzPYf2s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lzu.edu.cn; spf=pass smtp.mailfrom=lzu.edu.cn; arc=none smtp.client-ip=162.243.161.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=lzu.edu.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lzu.edu.cn Received: from enjou-Legion-Y7000P-2019 (unknown [219.141.235.82]) by app1 (Coremail) with SMTP id ygmowACXs73IMsxqh4xaAg--.62157S3; Mon, 12 Oct 2026 09:07:22 +0800 (CST) From: Ren Wei To: netdev@vger.kernel.org, kuba@kernel.org, pabeni@redhat.com Cc: jhs@mojatatu.com, jiri@resnulli.us, davem@davemloft.net, edumazet@kernel.org, horms@kernel.org, vladbu@mellanox.com, sbrivio@redhat.com, bird@lzu.edu.cn, kanolyc@gmail.com, z1652074432@gmail.com, n05ec@lzu.edu.cn Subject: [PATCH net v3 1/1] net/sched: cls_flower: avoid stale mask references after delete Date: Mon, 12 Oct 2026 09:07:19 +0800 Message-ID: <20261012010720.2248662-2-n05ec@lzu.edu.cn> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261012010720.2248662-1-n05ec@lzu.edu.cn> References: <20261012010720.2248662-1-n05ec@lzu.edu.cn> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CM-TRANSID:ygmowACXs73IMsxqh4xaAg--.62157S3 X-Coremail-Antispam: 1UD129KBjvJXoW3Gr4fJFWUJr48Cr13XF1fZwb_yoWxJw4UpF ZxG3y5tr4kGF4UWanYyw4UZ3ZIywn2ya98CF1fK34kJr15ta1fKFy7tayI9rWrCryxu3W5 GF4UK398ua1DAFJanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUBY1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW0oVCq3wA2z4x0Y4vEx4A2 jsIE14v26rxl6s0DM28EF7xvwVC2z280aVCY1x0267AKxVW0oVCq3wAS0I0E0xvYzxvE52 x082IY62kv0487Mc02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUJVWU GwAv7VC2z280aVAFwI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcxkI7VAKI4 8JM4x0x7Aq67IIx4CEVc8vx2IErcIFxwACI402YVCY1x02628vn2kIc2xKxwCY1x0262kK e7AKxVWUtVW8ZwCY02Avz4vE14v_KwCF04k20xvY0x0EwIxGrwCF04k20xvE74AGY7Cv6c x26r4rMxC20s026xCaFVCjc4AY6r1j6r4UMI8I3I0E5I8CrVAFwI0_Jr0_Jr4lx2IqxVCj r7xvwVAFwI0_JrI_JrWlx4CE17CEb7AF67AKxVWUtVW8ZwCIc40Y0x0EwIxGrwCI42IY6x IIjxv20xvE14v26r1j6r1xMIIF0xvE2Ix0cI8IcVCY1x0267AKxVW8JVWxJwCI42IY6xAI w20EY4v20xvaj40_Jr0_JF4lIxAIcVC2z280aVAFwI0_Jr0_Gr1lIxAIcVC2z280aVCY1x 0267AKxVW8JVW8JrUvcSsGvfC2KfnxnUUI43ZEXa7VUbl_M3UUUUU== X-CM-SenderInfo: zqqvvuo6o23hxhgxhubq/1tbiAQsSCWrK6DcK2QAAs9 From: Yuhang Zheng Flower releases a mask reference when a filter is removed from the classifier. The filter object can remain alive while dump, walk, or hardware reoffload paths hold a reference to it. Those paths can then dereference f->mask after the mask has already been released. Keep the mask reference until the filter reference count reaches zero. Release the mask synchronously from the final __fl_put() while the caller still holds the tcf_proto reference, and leave the existing RCU work to free the mask. This keeps the mask available to every reader that still holds the filter. The filter is still removed from the classifier indexes immediately. Therefore, a deleted filter can temporarily retain an otherwise empty mask; fl_delete() uses the handle IDR, rather than the mask list, to determine whether the classifier has become empty. Failed mask assignment can leave fnew->mask as an error or borrowed pointer without an owned mask reference. Clear it before the common failure path so the final put cannot release an unowned reference. This fix does not add fields, snapshots, or per-filter memory. Fixes: 92149190067d ("net: sched: flower: set unlocked flag for flower proto ops") Cc: stable@vger.kernel.org Reported-by: Xin Liu Tested-by: Yucheng Lu Signed-off-by: Yuhang Zheng Signed-off-by: Ren Wei --- net/sched/cls_flower.c | 50 +++++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 22 deletions(-) diff --git a/net/sched/cls_flower.c b/net/sched/cls_flower.c index 1cefea571efd..92a7f2d6efc0 100644 --- a/net/sched/cls_flower.c +++ b/net/sched/cls_flower.c @@ -518,15 +518,22 @@ static void fl_hw_update_stats(struct tcf_proto *tp, struct cls_fl_filter *f, tcf_exts_hw_stats_update(&f->exts, &cls_flower.stats, cls_flower.use_act_stats); } -static void __fl_put(struct cls_fl_filter *f) +static bool __fl_put(struct tcf_proto *tp, struct cls_fl_filter *f) { + bool last = false; + if (!refcount_dec_and_test(&f->refcnt)) - return; + return false; + + if (f->mask) + last = fl_mask_put(fl_head_dereference(tp), f->mask); if (tcf_exts_get_net(&f->exts)) tcf_queue_work(&f->rwork, fl_destroy_filter_work); else __fl_destroy_filter(f); + + return last; } static struct cls_fl_filter *__fl_get(struct cls_fl_head *head, u32 handle) @@ -572,11 +579,10 @@ static int __fl_delete(struct tcf_proto *tp, struct cls_fl_filter *f, list_del_rcu(&f->list); spin_unlock(&tp->lock); - *last = fl_mask_put(head, f->mask); if (!tc_skip_hw(f->flags)) fl_hw_destroy_filter(tp, f, rtnl_held, extack); tcf_unbind_filter(tp, &f->res); - __fl_put(f); + *last = __fl_put(tp, f); return 0; } @@ -617,7 +623,7 @@ static void fl_put(struct tcf_proto *tp, void *arg) { struct cls_fl_filter *f = arg; - __fl_put(f); + __fl_put(tp, f); } static void *fl_get(struct tcf_proto *tp, u32 handle) @@ -2488,12 +2494,14 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, } err = fl_check_assign_mask(head, fnew, fold, mask); - if (err) + if (err) { + fnew->mask = NULL; goto unbind_filter; + } err = fl_ht_insert_unique(fnew, fold, &in_ht); if (err) - goto errout_mask; + goto unbind_filter; if (!tc_skip_hw(fnew->flags)) { err = fl_hw_replace_filter(tp, fnew, rtnl_held, extack); @@ -2547,7 +2555,6 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, spin_unlock(&tp->lock); - fl_mask_put(head, fold->mask); if (!tc_skip_hw(fold->flags)) fl_hw_destroy_filter(tp, fold, rtnl_held, NULL); tcf_unbind_filter(tp, &fold->res); @@ -2555,7 +2562,7 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, * after this. */ refcount_dec(&fold->refcnt); - __fl_put(fold); + __fl_put(tp, fold); } else { idr_replace(&head->handle_idr, fnew, fnew->handle); @@ -2580,9 +2587,6 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, if (in_ht) rhashtable_remove_fast(&fnew->mask->ht, &fnew->ht_node, fnew->mask->filter_ht_params); -errout_mask: - fl_mask_put(head, fnew->mask); - unbind_filter: if (bound_to_filter) { if (flags & TCA_ACT_FLAGS_NO_RTNL) @@ -2598,14 +2602,14 @@ static int fl_change(struct net *net, struct sk_buff *in_skb, idr_remove(&head->handle_idr, fnew->handle); spin_unlock(&tp->lock); } - __fl_put(fnew); + __fl_put(tp, fnew); errout_tb: kfree(tb); errout_mask_alloc: tcf_queue_work(&mask->rwork, fl_uninit_mask_free_work); errout_fold: if (fold) - __fl_put(fold); + __fl_put(tp, fold); return err; } @@ -2618,8 +2622,10 @@ static int fl_delete(struct tcf_proto *tp, void *arg, bool *last, int err = 0; err = __fl_delete(tp, f, &last_on_mask, rtnl_held, extack); - *last = list_empty(&head->masks); - __fl_put(f); + spin_lock(&tp->lock); + *last = idr_is_empty(&head->handle_idr); + spin_unlock(&tp->lock); + __fl_put(tp, f); return err; } @@ -2641,12 +2647,12 @@ static void fl_walk(struct tcf_proto *tp, struct tcf_walker *arg, rcu_read_unlock(); if (arg->fn(tp, f, arg) < 0) { - __fl_put(f); + __fl_put(tp, f); arg->stop = 1; rcu_read_lock(); break; } - __fl_put(f); + __fl_put(tp, f); arg->count++; rcu_read_lock(); } @@ -2697,7 +2703,7 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb, cls_flower.rule = flow_rule_alloc(tcf_exts_num_actions(&f->exts)); if (!cls_flower.rule) { - __fl_put(f); + __fl_put(tp, f); return -ENOMEM; } @@ -2715,7 +2721,7 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb, if (err) { kfree(cls_flower.rule); if (tc_skip_sw(f->flags)) { - __fl_put(f); + __fl_put(tp, f); return err; } goto next_flow; @@ -2731,11 +2737,11 @@ static int fl_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb, kfree(cls_flower.rule); if (err) { - __fl_put(f); + __fl_put(tp, f); return err; } next_flow: - __fl_put(f); + __fl_put(tp, f); } return 0; -- 2.52.0