From patchwork Mon Mar 27 21:02:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Richard Acayan X-Patchwork-Id: 13190087 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 64E67C6FD1D for ; Mon, 27 Mar 2023 21:03:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231958AbjC0VD0 (ORCPT ); Mon, 27 Mar 2023 17:03:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231977AbjC0VDZ (ORCPT ); Mon, 27 Mar 2023 17:03:25 -0400 Received: from mail-yb1-xb36.google.com (mail-yb1-xb36.google.com [IPv6:2607:f8b0:4864:20::b36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 14B96271C; Mon, 27 Mar 2023 14:03:07 -0700 (PDT) Received: by mail-yb1-xb36.google.com with SMTP id cf7so12485360ybb.5; Mon, 27 Mar 2023 14:03:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1679950986; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=WSzUASJDqmk05kc24FOpZeQYr3X2iF7C+bvKtga/9zY=; b=DuVyGK5jAPiKnMlo3gU6hpcJlp8HDMLAP1nJQQjmnCqbJFOW1gNNxBNc0OLl/GN71Q evi/fD/5bdtx/GSM/0P1o0pMiEfjk85bs8fcCmsOeM6fbxCkKCQysa6Uy1HX8sejUyoN so/PsIzzOIOTQOr+mJ+SglXLD40pJ3h5Qy4ms/eZnuorA8hHlTeTl0g+69ujzt0BgpX+ 7vXFCuoXpj/MCa1Qh1KZSvW1XLrEy7ujo82qdjfirrpSZGlV6TEmLbseGogGAeW4atYK 7qIFAP7tkD8m76YoVEobhtU5PDbTNRHiwiCRCxvXTNyNtbzBOtEDq10vj5bIIU2L6Pjo 1ecQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1679950986; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=WSzUASJDqmk05kc24FOpZeQYr3X2iF7C+bvKtga/9zY=; b=h7RlxtIQCrRDtwtbAr8UyxvLE78LUNva1YU4KOKfTFjywFyp2hOu0V82ZOZBQ9VvHI 0M6mTAsyKtE7BmkY6wpxfpkO/Curl7ykpPzYTFj7Itqs0mvqgsaZ9Q3/wcJvVUWVuiPm 7ddCef+vz7XfszeTzzg6TpLTr+KKx1sKwvXrLzesBRhha+RXMizp2hULm/MMhUmTgoZP BZE0TXRNqGgIWHfGaWFbRe80p/TyHLCyFQb12jdQWsSOZo0pvMVyT/Ng100d/pGWGWEu X6bdR42EqxWfOY2tRgJb3O4iiQNMBSKMVyLv/G3nvElj2SLCj+YCn0xXoZYk+iBahtPC cKJA== X-Gm-Message-State: AAQBX9esc/JCMfmZI9TZK7w5N1Lba9MKCCyObgXu3Atd1y56EADN0iEo BL23F1+/SFYo/lG9PfVaqPc= X-Google-Smtp-Source: AKy350b6hIWzNa11aqhiXM04lQXVpTScEhhafaJJz9+qWPhPN8ftANifZPQ7/9ZhMvQBPXP3vzOTRA== X-Received: by 2002:a25:24a:0:b0:b48:e4e:eddd with SMTP id 71-20020a25024a000000b00b480e4eedddmr13151269ybc.25.1679950986253; Mon, 27 Mar 2023 14:03:06 -0700 (PDT) Received: from localhost ([2607:fea8:529d:4d00::9f37]) by smtp.gmail.com with ESMTPSA id p8-20020a254208000000b00b7767ca7476sm2511400yba.19.2023.03.27.14.03.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 27 Mar 2023 14:03:05 -0700 (PDT) From: Richard Acayan To: Srinivas Kandagatla , Amol Maheshwari , Arnd Bergmann , Greg Kroah-Hartman , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Richard Acayan Subject: [PATCH v2 2/2] misc: fastrpc: reject new invocations during device removal Date: Mon, 27 Mar 2023 17:02:18 -0400 Message-Id: <20230327210217.60948-3-mailingradian@gmail.com> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230327210217.60948-1-mailingradian@gmail.com> References: <20230327210217.60948-1-mailingradian@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org The channel's rpmsg object allows new invocations to be made. After old invocations are already interrupted, the driver shouldn't try to invoke anymore. Invalidating the rpmsg at the end of the driver removal function makes it easy to cause a race condition in userspace. Even closing a file descriptor before the driver finishes its cleanup can cause an invocation via fastrpc_release_current_dsp_process() and subsequent timeout. Invalidate the channel before the invocations are interrupted to make sure that no invocations can be created to hang after the device closes. Fixes: c68cfb718c8f ("misc: fastrpc: Add support for context Invoke method") Signed-off-by: Richard Acayan --- Demonstration of the bug as performed on a Google Pixel 3a with devicetree patches: #include #include #include #include #include #include #include static int remotectl_open(int fd, const char *name, uint32_t *handle) { struct fastrpc_invoke invoke; struct fastrpc_invoke_args args[4]; struct { uint32_t namelen; uint32_t errlen; } in; struct { uint32_t handle; uint32_t err; } out; char errstr[256]; int ret; // Remoteproc expects to receive a null terminator in.namelen = strlen(name) + 1; in.errlen = 256; args[0].ptr = (__u64) ∈ args[0].length = sizeof(in); args[0].fd = -1; args[1].ptr = (__u64) name; args[1].length = in.namelen; args[1].fd = -1; args[2].ptr = (__u64) &out; args[2].length = sizeof(out); args[2].fd = -1; args[3].ptr = (__u64) errstr; args[3].length = 256; args[3].fd = -1; invoke.handle = 0; invoke.sc = 0x00020200; invoke.args = (__u64) args; ret = ioctl(fd, FASTRPC_IOCTL_INVOKE, (__u64) &invoke); if (!ret) *handle = out.handle; return ret; } int main() { struct fastrpc_init_create_static create; uint32_t handle; int fd, ret; fd = open("/dev/fastrpc-adsp", O_RDWR); if (fd == -1) { perror("Could not open /dev/fastrpc-adsp"); return 1; } ret = ioctl(fd, FASTRPC_IOCTL_INIT_ATTACH_SNS, NULL); if (ret) { perror("Could not attach to sensorspd"); goto close_dev; } /* * Under normal circumstances, the remote processor * would request a file from a different client, and * quickly find out that there is no such file. When * this other client is not running, this procedure call * conveniently waits for the ADSP to crash. */ ret = remotectl_open(fd, "a", &handle); if (ret == -1) perror("Could not open CHRE interface"); close_dev: // This takes 10 seconds printf("Closing file descriptor\n"); close(fd); printf("Closed file descriptor\n"); return 0; } --- drivers/misc/fastrpc.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c index 20c035af373a..f4116ce7805a 100644 --- a/drivers/misc/fastrpc.c +++ b/drivers/misc/fastrpc.c @@ -2351,7 +2351,9 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev) struct fastrpc_user *user; unsigned long flags; + /* No invocations past this point */ spin_lock_irqsave(&cctx->lock, flags); + cctx->rpdev = NULL; list_for_each_entry(user, &cctx->users, user) fastrpc_notify_users(user); spin_unlock_irqrestore(&cctx->lock, flags); @@ -2370,7 +2372,6 @@ static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev) of_platform_depopulate(&rpdev->dev); - cctx->rpdev = NULL; fastrpc_channel_ctx_put(cctx); }