From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 BFBCF63D5; Sat, 30 Dec 2023 12:02:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ie9tGqAl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E321AC433C7; Sat, 30 Dec 2023 12:02:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1703937772; bh=/zk8VSXywc0lfwM9197BuohbrZpv1j7R5GekcFigEIQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ie9tGqAlpcBEAZHrjmKUftANUokZFA5V5wdWYso2gdqhrNeJzH6v0JJSnUx005Zky WUxmWeP5r1xWS/l138Avoj7CHVWQZEyUORjQl4jmxUuM818LiZ3YrSq6zNvAfQeaak DnYyyeE8kjd92/HV1OJ+tWBIRtag9oE+e36E2PPM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Moshe Shemesh , Shifeng Li , Saeed Mahameed , Sasha Levin Subject: [PATCH 6.6 033/156] net/mlx5e: Fix a race in command alloc flow Date: Sat, 30 Dec 2023 11:58:07 +0000 Message-ID: <20231230115813.456617014@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231230115812.333117904@linuxfoundation.org> References: <20231230115812.333117904@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org 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: Shifeng Li [ Upstream commit 8f5100da56b3980276234e812ce98d8f075194cd ] Fix a cmd->ent use after free 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 allocated a ent->idx but didn't set ent to cmd->ent_arr in cmd_work_handler(). Fix it by moving the assignment of cmd->ent_arr into the spin lock. [70013.081955] BUG: KASAN: use-after-free in mlx5_cmd_trigger_completions+0x1e2/0x4c0 [mlx5_core] [70013.081967] Write of size 4 at addr ffff88880b1510b4 by task kworker/26:1/1433361 [70013.081968] [70013.082028] Workqueue: events aer_isr [70013.082053] Call Trace: [70013.082067] dump_stack+0x8b/0xbb [70013.082086] print_address_description+0x6a/0x270 [70013.082102] kasan_report+0x179/0x2c0 [70013.082173] mlx5_cmd_trigger_completions+0x1e2/0x4c0 [mlx5_core] [70013.082267] mlx5_cmd_flush+0x80/0x180 [mlx5_core] [70013.082304] mlx5_enter_error_state+0x106/0x1d0 [mlx5_core] [70013.082338] mlx5_try_fast_unload+0x2ea/0x4d0 [mlx5_core] [70013.082377] remove_one+0x200/0x2b0 [mlx5_core] [70013.082409] pci_device_remove+0xf3/0x280 [70013.082439] device_release_driver_internal+0x1c3/0x470 [70013.082453] pci_stop_bus_device+0x109/0x160 [70013.082468] pci_stop_and_remove_bus_device+0xe/0x20 [70013.082485] pcie_do_fatal_recovery+0x167/0x550 [70013.082493] aer_isr+0x7d2/0x960 [70013.082543] process_one_work+0x65f/0x12d0 [70013.082556] worker_thread+0x87/0xb50 [70013.082571] kthread+0x2e9/0x3a0 [70013.082592] ret_from_fork+0x1f/0x40 The logical relationship of this error is as follows: aer_recover_work | ent->work -------------------------------------------+------------------------------ aer_recover_work_func | |- pcie_do_recovery | |- report_error_detected | |- mlx5_pci_err_detected |cmd_work_handler |- mlx5_enter_error_state | |- cmd_alloc_index |- enter_error_state | |- lock cmd->alloc_lock |- mlx5_cmd_flush | |- clear_bit |- mlx5_cmd_trigger_completions| |- unlock cmd->alloc_lock |- lock cmd->alloc_lock | |- vector = ~dev->cmd.vars.bitmask |- for_each_set_bit | |- cmd_ent_get(cmd->ent_arr[i]) (UAF) |- unlock cmd->alloc_lock | |- cmd->ent_arr[ent->idx]=ent The cmd->ent_arr[ent->idx] assignment and the bit clearing are not protected by the cmd->alloc_lock in cmd_work_handler(). Fixes: 50b2412b7e78 ("net/mlx5: Avoid possible free of command entry while timeout comp handler") Reviewed-by: Moshe Shemesh Signed-off-by: Shifeng Li Signed-off-by: Saeed Mahameed Signed-off-by: Sasha Levin --- drivers/net/ethernet/mellanox/mlx5/core/cmd.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c index c22b0ad0c8701..7013e1c8741a3 100644 --- a/drivers/net/ethernet/mellanox/mlx5/core/cmd.c +++ b/drivers/net/ethernet/mellanox/mlx5/core/cmd.c @@ -156,15 +156,18 @@ static u8 alloc_token(struct mlx5_cmd *cmd) return token; } -static int cmd_alloc_index(struct mlx5_cmd *cmd) +static int cmd_alloc_index(struct mlx5_cmd *cmd, struct mlx5_cmd_work_ent *ent) { unsigned long flags; int ret; spin_lock_irqsave(&cmd->alloc_lock, flags); ret = find_first_bit(&cmd->vars.bitmask, cmd->vars.max_reg_cmds); - if (ret < cmd->vars.max_reg_cmds) + if (ret < cmd->vars.max_reg_cmds) { clear_bit(ret, &cmd->vars.bitmask); + ent->idx = ret; + cmd->ent_arr[ent->idx] = ent; + } spin_unlock_irqrestore(&cmd->alloc_lock, flags); return ret < cmd->vars.max_reg_cmds ? ret : -ENOMEM; @@ -977,7 +980,7 @@ static void cmd_work_handler(struct work_struct *work) sem = ent->page_queue ? &cmd->vars.pages_sem : &cmd->vars.sem; down(sem); if (!ent->page_queue) { - alloc_ret = cmd_alloc_index(cmd); + alloc_ret = cmd_alloc_index(cmd, ent); if (alloc_ret < 0) { mlx5_core_err_rl(dev, "failed to allocate command entry\n"); if (ent->callback) { @@ -992,15 +995,14 @@ static void cmd_work_handler(struct work_struct *work) up(sem); return; } - ent->idx = alloc_ret; } else { ent->idx = cmd->vars.max_reg_cmds; spin_lock_irqsave(&cmd->alloc_lock, flags); clear_bit(ent->idx, &cmd->vars.bitmask); + cmd->ent_arr[ent->idx] = ent; spin_unlock_irqrestore(&cmd->alloc_lock, flags); } - cmd->ent_arr[ent->idx] = ent; lay = get_inst(cmd, ent->idx); ent->lay = lay; memset(lay, 0, sizeof(*lay)); -- 2.43.0