From patchwork Mon Mar 14 11:53:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 551718 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 22D3CC4167E for ; Mon, 14 Mar 2022 12:10:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240522AbiCNMLs (ORCPT ); Mon, 14 Mar 2022 08:11:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52926 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242660AbiCNMKa (ORCPT ); Mon, 14 Mar 2022 08:10:30 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6C66D31531; Mon, 14 Mar 2022 05:09:20 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2A4CBB80DF3; Mon, 14 Mar 2022 12:09:19 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 23928C340E9; Mon, 14 Mar 2022 12:09:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1647259758; bh=08Tqei4Z8WFHO1qIRIw00Kq9v5Z7hksfudfirAx5M+I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=npNaCh1KGWidY6SExVtM3DVemAdKEtlDi9sSRH4jS8Cwtw+37KOKr0HMzx3mqRB5n S4BW72Pxkqq4Fv37wYHgKUHycu40uzMN52rqlAGDCDwJ7qpaXhBLvXkN9oaFOoZOQ/ GwQAuVSGmYoM/ey082qoQwBhOpuJ3zritq0/UhIE= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Moshe Shemesh , Eran Ben Elisha , Saeed Mahameed , Sasha Levin Subject: [PATCH 5.15 041/110] net/mlx5: Fix a race on command flush flow Date: Mon, 14 Mar 2022 12:53:43 +0100 Message-Id: <20220314112744.184811656@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220314112743.029192918@linuxfoundation.org> References: <20220314112743.029192918@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Moshe Shemesh [ Upstream commit 063bd355595428750803d8736a9bb7c8db67d42d ] Fix a refcount use after free warning due to a race on command entry. Such race occurs when one of the commands releases its last refcount and frees its index and entry while another process running command flush flow takes refcount to this command entry. The process which handles commands flush may see this command as needed to be flushed if the other process released its refcount but didn't release the index yet. Fix it by adding the needed spin lock. It fixes the following warning trace: refcount_t: addition on 0; use-after-free. WARNING: CPU: 11 PID: 540311 at lib/refcount.c:25 refcount_warn_saturate+0x80/0xe0 ... RIP: 0010:refcount_warn_saturate+0x80/0xe0 ... Call Trace: mlx5_cmd_trigger_completions+0x293/0x340 [mlx5_core] mlx5_cmd_flush+0x3a/0xf0 [mlx5_core] enter_error_state+0x44/0x80 [mlx5_core] mlx5_fw_fatal_reporter_err_work+0x37/0xe0 [mlx5_core] process_one_work+0x1be/0x390 worker_thread+0x4d/0x3d0 ? rescuer_thread+0x350/0x350 kthread+0x141/0x160 ? set_kthread_struct+0x40/0x40 ret_from_fork+0x1f/0x30 Fixes: 50b2412b7e78 ("net/mlx5: Avoid possible free of command entry while timeout comp handler") Signed-off-by: Moshe Shemesh Reviewed-by: Eran Ben Elisha Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c index 00f63fbfe9b4..e06a6104e91f 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c @@ -130,11 +130,8 @@ static int cmd_alloc_index(struct mlx5_cmd *cmd) static void cmd_free_index(struct mlx5_cmd *cmd, int idx) { - unsigned long flags; - - spin_lock_irqsave(&cmd->alloc_lock, flags); + lockdep_assert_held(&cmd->alloc_lock); set_bit(idx, &cmd->bitmask); - spin_unlock_irqrestore(&cmd->alloc_lock, flags); } static void cmd_ent_get(struct mlx5_cmd_work_ent *ent) @@ -144,17 +141,21 @@ static void cmd_ent_get(struct mlx5_cmd_work_ent *ent) static void cmd_ent_put(struct mlx5_cmd_work_ent *ent) { + struct mlx5_cmd *cmd = ent->cmd; + unsigned long flags; + + spin_lock_irqsave(&cmd->alloc_lock, flags); if (!refcount_dec_and_test(&ent->refcnt)) - return; + goto out; if (ent->idx >= 0) { - struct mlx5_cmd *cmd = ent->cmd; - cmd_free_index(cmd, ent->idx); up(ent->page_queue ? &cmd->pages_sem : &cmd->sem); } cmd_free_ent(ent); +out: + spin_unlock_irqrestore(&cmd->alloc_lock, flags); } static struct mlx5_cmd_layout *get_inst(struct mlx5_cmd *cmd, int idx)