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 BBF9046EF7B; Tue, 21 Jul 2026 20:28:41 +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=1784665722; cv=none; b=uYIfW0XEGUshENWrNVr6q5iArNaL6dBOGvD40/F1TXzM8jOuMp5Ui4TapeiBPDzR6QLiGnaKDOvPFn6g6M3Nk8ZpxnvPxzb4TlfQPC9JRNSQNW94s4Pe0+jExXHEOQC2TclrKvl7rrehqABPi1EIdS9U6/v0VVLl2BcbxZk5ARE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784665722; c=relaxed/simple; bh=GFWvYLrsXPr0jOg/KwY215jHUtvy1zIsJUWjhH6Q4ds=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=moJ6rdKQlA+R/32fT7uV2Li7whB0At9nbdj2T2etnRkSeWaQmPzBlI7hJu+WCszJvwN77dxFvUoMqsBf6/WVXXa/0bAUEq1cY2V4N84MVQ08/leH7yao3JFLCJ1FKGQMqCu5oOY4w3AHoBvQbxaP5rsO7z3Ektz9ZmLdRK5vQQ0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Chcl0UKm; 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="Chcl0UKm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F34191F000E9; Tue, 21 Jul 2026 20:28:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784665721; bh=WJp9LUh31dOr06Y5b7Aack8ZePF+RLjTUZH64QUGsXM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Chcl0UKmnLKRWfmpijalnNG/6VQeBf46Xe2i2wqWMA1rGCOF6eVbVoUGR3FQ7bDP7 wgP3NADGZ0HlaCISGgBh9pFMpfn9/CRPtIjgzq3zrl1PcVBnN6Sh0fkbgAGffwPI9B jrIk3JVE/dlYiw7bXl7k/uAtlcr4xzzGW2XJDZkg= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Prathamesh Deshpande , Yishai Hadas , Leon Romanovsky , Sasha Levin Subject: [PATCH 6.6 0409/1266] RDMA/mlx5: Fix devx subscribe-event unwind NULL dereference Date: Tue, 21 Jul 2026 17:14:06 +0200 Message-ID: <20260721152450.989078918@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260721152441.786066624@linuxfoundation.org> References: <20260721152441.786066624@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 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Prathamesh Deshpande [ Upstream commit 43f8f7946814c8e5f464518246fdbc69b6e32326 ] MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT() links event_sub into sub_list before initializing the fields used by the shared error path. If eventfd_ctx_fdget() then fails, the unwind path dereferences event_sub->ev_file in uverbs_uobject_put() and calls subscribe_event_xa_dealloc() with an unset xa_key_level1. subscribe_event_xa_alloc() creates the XA entry exactly once for a given key_level1, on the first occurrence of that key. The unwind path must therefore call subscribe_event_xa_dealloc() exactly once for it as well. Enforce that by adding devx_key_in_sub_list() and calling subscribe_event_xa_dealloc() only when the last matching pending entry is being cleaned up. Fixes: 759738537142 ("IB/mlx5: Enable subscription for device events over DEVX") Signed-off-by: Prathamesh Deshpande Link: https://patch.msgid.link/20260428224319.37682-1-prathameshdeshpande7@gmail.com Reviewed-by: Yishai Hadas Signed-off-by: Leon Romanovsky Signed-off-by: Sasha Levin --- drivers/infiniband/hw/mlx5/devx.c | 30 +++++++++++++++++++++++------- 1 file changed, 23 insertions(+), 7 deletions(-) diff --git a/drivers/infiniband/hw/mlx5/devx.c b/drivers/infiniband/hw/mlx5/devx.c index 388c95562a927a..0aee5738e2984e 100644 --- a/drivers/infiniband/hw/mlx5/devx.c +++ b/drivers/infiniband/hw/mlx5/devx.c @@ -1851,6 +1851,17 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_OBJ_ASYNC_QUERY)( return err; } +static bool devx_key_in_sub_list(struct list_head *list, u32 key_level1) +{ + struct devx_event_subscription *s; + + list_for_each_entry(s, list, event_list) + if (s->xa_key_level1 == key_level1) + return true; + + return false; +} + static void subscribe_event_xa_dealloc(struct mlx5_devx_event_table *devx_event_table, u32 key_level1, @@ -2098,10 +2109,17 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT)( event_sub = kzalloc(sizeof(*event_sub), GFP_KERNEL); if (!event_sub) { + if (!devx_key_in_sub_list(&sub_list, key_level1)) + subscribe_event_xa_dealloc(devx_event_table, + key_level1, + obj, + obj_id); err = -ENOMEM; goto err; } + event_sub->ev_file = ev_file; + event_sub->xa_key_level1 = key_level1; list_add_tail(&event_sub->event_list, &sub_list); uverbs_uobject_get(&ev_file->uobj); if (use_eventfd) { @@ -2116,9 +2134,6 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT)( } event_sub->cookie = cookie; - event_sub->ev_file = ev_file; - /* May be needed upon cleanup the devx object/subscription */ - event_sub->xa_key_level1 = key_level1; event_sub->xa_key_level2 = obj_id; INIT_LIST_HEAD(&event_sub->obj_list); } @@ -2163,10 +2178,11 @@ static int UVERBS_HANDLER(MLX5_IB_METHOD_DEVX_SUBSCRIBE_EVENT)( list_for_each_entry_safe(event_sub, tmp_sub, &sub_list, event_list) { list_del(&event_sub->event_list); - subscribe_event_xa_dealloc(devx_event_table, - event_sub->xa_key_level1, - obj, - obj_id); + if (!devx_key_in_sub_list(&sub_list, event_sub->xa_key_level1)) + subscribe_event_xa_dealloc(devx_event_table, + event_sub->xa_key_level1, + obj, + obj_id); if (event_sub->eventfd) eventfd_ctx_put(event_sub->eventfd); -- 2.53.0