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 0B68F370AFB; Tue, 21 Jul 2026 22:04:06 +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=1784671447; cv=none; b=rko0lAR+siUv3YKOR78u1McSNcqjwUnUc6A4sS1ONK2nnulgMAr2IwyjQ3zSjpSQiZJtvkWdDAEDw+1/4rGyAxT+WZwfak9FvsD7AMlHcGnhMhJhapjyeFCXGX5YqwldpbAHrH9gRoBV4ErjzZf3rgRe2jeWOZfCO5T0ZO44RrI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784671447; c=relaxed/simple; bh=CtzeD9Au0sk2Bxvca0HPc7xxcWrG7MLlTryk3nXLjjc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ay5r+Mx51A1mpRES2rBLOHtCyH1mtccwLAV5kfiNexxWsGRbIj9ykoh/c4rvyZCaSAMckyNei5YIbaC3mpIcySdzAbwy6/rQ4bveWpmi3uCk65Sjq9ec6mgzc8KEaaKCvpWumcCIkxRPZng63+pzDeqWkrTVMYe6lsKe6sdsVkU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RL33D20w; 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="RL33D20w" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6FF071F000E9; Tue, 21 Jul 2026 22:04:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784671445; bh=ZtITLX4HsVyQHyjZXpi4zELR546fFyBDszVbzsuj1OM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=RL33D20wQTcIhoZrlBkJiOb2Y6mQCEZZc29PvvTtlvRc8KhbnheUUMUj/gIMlEakE CZMhR9j3unrHSv/42ztJ4JCNCKIP4S36UxeOsNDRawRbYxMAWsEhxTxalLoEsh5N1w 8gojdPDUXwuD5KlQVigBpgMEfAsWr0EdfXhdnqUk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Jakub Kicinski , Sasha Levin Subject: [PATCH 5.15 248/843] net/sched: sch_drr: annotate data-races around cl->deficit Date: Tue, 21 Jul 2026 17:18:03 +0200 Message-ID: <20260721152411.599295849@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152405.946368001@linuxfoundation.org> References: <20260721152405.946368001@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 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit c67b104fd7982162885c5e43057ca761006748e2 ] drr_dump_class_stats() runs without qdisc spinlock held. Add missing READ_ONCE()/WRITE_ONCE() annotations around cl->deficit. Fixes: edb09eb17ed8 ("net: sched: do not acquire qdisc spinlock in qdisc/class stats dump") Signed-off-by: Eric Dumazet Link: https://patch.msgid.link/20260519094618.2632073-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/sched/sch_drr.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/net/sched/sch_drr.c b/net/sched/sch_drr.c index 5a543d35d53b8d..a2b9802d41c010 100644 --- a/net/sched/sch_drr.c +++ b/net/sched/sch_drr.c @@ -271,7 +271,7 @@ static int drr_dump_class_stats(struct Qdisc *sch, unsigned long arg, memset(&xstats, 0, sizeof(xstats)); if (qlen) - xstats.deficit = cl->deficit; + xstats.deficit = READ_ONCE(cl->deficit); if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch), d, NULL, &cl->bstats) < 0 || @@ -371,7 +371,7 @@ static int drr_enqueue(struct sk_buff *skb, struct Qdisc *sch, if (!cl_is_active(cl)) { list_add_tail(&cl->alist, &q->active); - cl->deficit = cl->quantum; + WRITE_ONCE(cl->deficit, cl->quantum); } sch->qstats.backlog += len; @@ -398,7 +398,7 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch) len = qdisc_pkt_len(skb); if (len <= cl->deficit) { - cl->deficit -= len; + WRITE_ONCE(cl->deficit, cl->deficit - len); skb = qdisc_dequeue_peeked(cl->qdisc); if (unlikely(skb == NULL)) goto out; @@ -412,7 +412,7 @@ static struct sk_buff *drr_dequeue(struct Qdisc *sch) return skb; } - cl->deficit += cl->quantum; + WRITE_ONCE(cl->deficit, cl->deficit + cl->quantum); list_move_tail(&cl->alist, &q->active); } out: -- 2.53.0