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 3E8693101A5 for ; Thu, 3 Sep 2026 22:11:58 +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=1788473520; cv=none; b=Qhd92io53WQpSKQIJVd66MNnTa66rlP4Af2Fx3Q5DGWCVqMPrxgzKov5i8CHEzE03zuW+0e/ze/UgkWdV+lK5RTx87pXYtlWVPfrb5eRuzPR70Ibg7kO5gjn4V/wzgR6x0uE+WRXeSuFz64EcWBnNvWCt0XhSXqypJcKFESCAw4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788473520; c=relaxed/simple; bh=3BKwTGkO+Ww473i+r/eAg8qBrcgt4pm1pRuC6u6hkxs=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=PzgFtRFf2KNONxtV+A6WWo7oh0kBcjRtLWXaBbgiKzazYTUtB4PAxnxGkASCm4jr1aMoHL3BIJZt0LWfM+qQf5JVgADBZP8ANub0kjkkVw/yoeq3IAqpGXv8NWKYounSsk2B3uLRb4rlJoqs2GF626cqOblZf38NWMnrv4pYetQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=oKdzKuyR; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="oKdzKuyR" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3BA31F000E9; Thu, 3 Sep 2026 22:11:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788473518; bh=NGollT3DBRdVHQp8wLz0G4tcE7l5GOwoOWOLE2uWAwE=; h=From:To:Cc:Subject:Date; b=oKdzKuyRoo0wWfu0DcEAtE7jzFobIphmeHIKnxhrIU2vGBiBTXSXSUy8ou23VTaTw 1oIQWVr2zZJiyeFJ8ovFjuvx2fv+7+iziYgcqiWpRy5I11DlPDAtohvZBQ3+xqIRpu 6HEjLDvsdwMr5tON3lHBHL948zIJpCBeIEdKPuvEk1z5n/M13qdYLNTsT7R6sw39ul rzu61TCh2u8g8FYe7E6OKEmsS1wdEQjNXT7ThxpqS5f7bqDYeF7NUTs6v0pwE0Of7c lomu8y5LLrd5z0qwlfC7ihYejKjIZ5QKCeIQB6ghhD7wVw5gX9tI1pw6f26HXa9RIR KVskMWGs9k1VQ== From: Jakub Kicinski To: davem@davemloft.net Cc: netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, andrew+netdev@lunn.ch, horms@kernel.org, Jakub Kicinski , Bobby Eshleman , Daniel Borkmann , Nikolay Aleksandrov Subject: [PATCH net-next v3] netdev: avoid skipping objects on race with device disappearance Date: Thu, 3 Sep 2026 15:11:54 -0700 Message-ID: <20260903221154.3359889-1-kuba@kernel.org> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit If the currently dumped device disappears while we were mid-dump we will get the next device without resetting the sub-object ID. This is quite unlikely, it was reported by an AI tool not a real user. Let's fix it for better dump consistency. We only intend to cover the case where device A disappears and we skip over sub-objects of device B which was stable (B existed before and after the dump). We don't intend to provide stable results for any device that gets created or deleted during the dump. Reviewed-by: Bobby Eshleman Acked-by: Daniel Borkmann Reviewed-by: Nikolay Aleksandrov Signed-off-by: Jakub Kicinski --- v3: cover page pool dump as well v2: https://lore.kernel.org/20260831164159.1124679-3-kuba@kernel.org v1: https://lore.kernel.org/20260609190804.1137085-1-kuba@kernel.org --- net/core/netdev-genl.c | 22 +++++++++++++++++----- net/core/page_pool_user.c | 8 ++++++-- 2 files changed, 23 insertions(+), 7 deletions(-) diff --git a/net/core/netdev-genl.c b/net/core/netdev-genl.c index b8ba91cc93da..fa9edfdb32c2 100644 --- a/net/core/netdev-genl.c +++ b/net/core/netdev-genl.c @@ -312,11 +312,14 @@ int netdev_nl_napi_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb) err = -ENODEV; } } else { + unsigned long start_ifindex = ctx->ifindex; + for_each_netdev_lock_scoped(net, netdev, ctx->ifindex) { + if (ctx->ifindex != start_ifindex) + ctx->napi_id = 0; err = netdev_nl_napi_dump_one(netdev, skb, info, ctx); if (err < 0) break; - ctx->napi_id = 0; } } @@ -636,13 +639,17 @@ int netdev_nl_queue_get_dumpit(struct sk_buff *skb, struct netlink_callback *cb) err = -ENODEV; } } else { + unsigned long start_ifindex = ctx->ifindex; + for_each_netdev_lock_ops_compat_scoped(net, netdev, ctx->ifindex) { + if (ctx->ifindex != start_ifindex) { + ctx->rxq_idx = 0; + ctx->txq_idx = 0; + } err = netdev_nl_queue_dump_one(netdev, skb, info, ctx); if (err < 0) break; - ctx->rxq_idx = 0; - ctx->txq_idx = 0; } } @@ -788,8 +795,6 @@ netdev_nl_stats_by_queue(struct net_device *netdev, struct sk_buff *rsp, ctx->txq_idx = ++i; } - ctx->rxq_idx = 0; - ctx->txq_idx = 0; return 0; } @@ -904,6 +909,7 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, struct netdev_nl_dump_ctx *ctx = netdev_dump_ctx(cb); const struct genl_info *info = genl_info_dump(cb); struct net *net = sock_net(skb->sk); + unsigned long start_ifindex; struct net_device *netdev; unsigned int ifindex; unsigned int scope; @@ -936,7 +942,13 @@ int netdev_nl_qstats_get_dumpit(struct sk_buff *skb, return err; } + start_ifindex = ctx->ifindex; + for_each_netdev_lock_ops_compat_scoped(net, netdev, ctx->ifindex) { + if (ctx->ifindex != start_ifindex) { + ctx->rxq_idx = 0; + ctx->txq_idx = 0; + } err = netdev_nl_qstats_get_dump_one(netdev, scope, skb, info, ctx); if (err < 0) diff --git a/net/core/page_pool_user.c b/net/core/page_pool_user.c index ef4261c0e8ea..f30f3779624c 100644 --- a/net/core/page_pool_user.c +++ b/net/core/page_pool_user.c @@ -84,6 +84,7 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb, struct page_pool_dump_cb *state = (void *)cb->ctx; const struct genl_info *info = genl_info_dump(cb); struct net *net = sock_net(skb->sk); + unsigned long start_ifindex; struct net_device *netdev; struct page_pool *pool; int err = 0; @@ -91,6 +92,8 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb, if (ifindex_attr) state->ifindex = nla_get_u32(ifindex_attr); + start_ifindex = state->ifindex; + rtnl_lock(); mutex_lock(&page_pools_lock); for_each_netdev_dump(net, netdev, state->ifindex) { @@ -99,6 +102,9 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb, netdev->ifindex != nla_get_u32(ifindex_attr)) break; + if (state->ifindex != start_ifindex) + state->pp_id = 0; + hlist_for_each_entry(pool, &netdev->page_pools, user.list) { if (state->pp_id && state->pp_id < pool->user.id) continue; @@ -108,8 +114,6 @@ netdev_nl_page_pool_get_dump(struct sk_buff *skb, struct netlink_callback *cb, if (err) goto out; } - - state->pp_id = 0; } out: mutex_unlock(&page_pools_lock); -- 2.55.0