From patchwork Mon Jun 26 14:57:55 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chengfeng Ye X-Patchwork-Id: 697553 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 3DB62EB64D7 for ; Mon, 26 Jun 2023 14:58:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229736AbjFZO6G (ORCPT ); Mon, 26 Jun 2023 10:58:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59654 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229567AbjFZO6F (ORCPT ); Mon, 26 Jun 2023 10:58:05 -0400 Received: from mail-pl1-x62f.google.com (mail-pl1-x62f.google.com [IPv6:2607:f8b0:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4C306B6; Mon, 26 Jun 2023 07:58:04 -0700 (PDT) Received: by mail-pl1-x62f.google.com with SMTP id d9443c01a7336-1b7ef3e74edso6496965ad.0; Mon, 26 Jun 2023 07:58:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687791484; x=1690383484; h=message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=GIMrqRzfHWub21vEUbdFKshCviaaEWMt8gPIlJYyDLs=; b=U3ungQ8fHGGcylMOOqosJmHJnlcU3sF1O5EBKBNmbK3L8gpr4hBUl2IOnXWCtVEviy pzVCANghGEst5HffgmXoBrrRO/d9bU7h0g5vtpOUmWpjTcsiiPDcvSVINcBsY75/n318 teLsU0BIeSZtaUMn6jRwd8fbxrmH6Bez5K0joaEJ/z6VTTeu+mKXXbSmDisCMZ3fZ+DL 37s7aDvAYk2Bnutmna/HojmwvApTp/8BZJNqUgMnQWUg0Uky5bGFbEv8W6bhdivRZkpi oEqo7PMCHNyRObqUfVLdUFTwKV4lM1rrIL5g5f4qR16Qn2uixpFZgS/fZ3yKl0yIuCil l1eQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687791484; x=1690383484; h=message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=GIMrqRzfHWub21vEUbdFKshCviaaEWMt8gPIlJYyDLs=; b=TKkU/ODc6+5SWleKsSSRZMfvOU2gJ9WwM2eWq2m/8zH9lz9zp6d1s3P+yelN+qkSsK vIfXszZMKNMscCo0/AYha0/a48+sxVfptO2WXqtNSHiPB0NfqSbxIZf4Z3pT1kCwnkO2 +lAs0RXEbxcphz6z5DMe2vnuby47uuiLrmuFV3aRb6H5GmsXNhK83C5dHyTDtMc7Ri1C UiHskAQhqXa4KILscTSiN25W8QZXtYZAClN3VD87EZmzCJ8PNzJsLhXv+poQmhD8nRJE 93AAz8UrccuSIsE95JUoY0OKGrqmJwb5KYp6BMueoU47g2QUUQbd0yMnL8GTzrxoO0QK iT3A== X-Gm-Message-State: AC+VfDxFoaaJl4uPTrQ+8WUC799pumHBPG7aYbDPbPJL60PAFqRmcm3o Nro4PXVOmr4L/PfrcpYFCxY= X-Google-Smtp-Source: ACHHUZ6HlU8Ps9aOsuaLXOqRN3zvAGskznvY/bY5yG4B8Nuy4OmETZZA/SS3lLuefLjcBsmQgMygug== X-Received: by 2002:a17:902:6b4a:b0:1b7:e9e9:1004 with SMTP id g10-20020a1709026b4a00b001b7e9e91004mr2486269plt.30.1687791483643; Mon, 26 Jun 2023 07:58:03 -0700 (PDT) Received: from 377044c6c369.cse.ust.hk (191host097.mobilenet.cse.ust.hk. [143.89.191.97]) by smtp.gmail.com with ESMTPSA id x20-20020a170902821400b001b1a2bf5277sm4313303pln.39.2023.06.26.07.58.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Jun 2023 07:58:03 -0700 (PDT) From: Chengfeng Ye To: linus.walleij@linaro.org, brgl@bgdev.pl, andy@kernel.org Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, cyeaa@connect.ust.hk, Chengfeng Ye Subject: [PATCH v2 1/2] gpiolib: cdev: Fix &lr->wait.lock deadlock issue Date: Mon, 26 Jun 2023 14:57:55 +0000 Message-Id: <20230626145756.30696-1-dg573847474@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org linereq_put_event() is called from both interrupt context (e.g., edge_irq_thread()) and process context (process_hw_ts_thread()). Therefore, interrupt should be disabled before acquiring lock &lr->wait.lock inside linereq_put_event() to avoid deadlock when the lock is held in process context and edge_irq_thread() comes. Similarly, linereq_read_unlocked() running in process context also acquies the same lock. It also need to disable interrupt otherwise deadlock could happen if the irq edge_irq_thread() comes to execution while the lock is held. Fix the two potential deadlock issues by spin_lock_bh() and spin_lock_irq() separately. Fixes: 73e0341992b6 ("gpiolib: cdev: support edge detection for uAPI v2") Signed-off-by: Chengfeng Ye --- drivers/gpio/gpiolib-cdev.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index 0a33971c964c..f768d46bdea7 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -615,13 +615,13 @@ static void linereq_put_event(struct linereq *lr, { bool overflow = false; - spin_lock(&lr->wait.lock); + spin_lock_bh(&lr->wait.lock); if (kfifo_is_full(&lr->events)) { overflow = true; kfifo_skip(&lr->events); } kfifo_in(&lr->events, le, 1); - spin_unlock(&lr->wait.lock); + spin_unlock_bh(&lr->wait.lock); if (!overflow) wake_up_poll(&lr->wait, EPOLLIN); else @@ -1514,28 +1514,28 @@ static ssize_t linereq_read_unlocked(struct file *file, char __user *buf, return -EINVAL; do { - spin_lock(&lr->wait.lock); + spin_lock_irq(&lr->wait.lock); if (kfifo_is_empty(&lr->events)) { if (bytes_read) { - spin_unlock(&lr->wait.lock); + spin_unlock_irq(&lr->wait.lock); return bytes_read; } if (file->f_flags & O_NONBLOCK) { - spin_unlock(&lr->wait.lock); + spin_unlock_irq(&lr->wait.lock); return -EAGAIN; } - ret = wait_event_interruptible_locked(lr->wait, + ret = wait_event_interruptible_locked_irq(lr->wait, !kfifo_is_empty(&lr->events)); if (ret) { - spin_unlock(&lr->wait.lock); + spin_unlock_irq(&lr->wait.lock); return ret; } } ret = kfifo_out(&lr->events, &le, 1); - spin_unlock(&lr->wait.lock); + spin_unlock_irq(&lr->wait.lock); if (ret != 1) { /* * This should never happen - we were holding the From patchwork Mon Jun 26 14:57:56 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chengfeng Ye X-Patchwork-Id: 696703 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 4DA60EB64D7 for ; Mon, 26 Jun 2023 14:58:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229567AbjFZO6L (ORCPT ); Mon, 26 Jun 2023 10:58:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59674 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229922AbjFZO6K (ORCPT ); Mon, 26 Jun 2023 10:58:10 -0400 Received: from mail-pl1-x633.google.com (mail-pl1-x633.google.com [IPv6:2607:f8b0:4864:20::633]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1545101; Mon, 26 Jun 2023 07:58:08 -0700 (PDT) Received: by mail-pl1-x633.google.com with SMTP id d9443c01a7336-1b7f68f1c9eso14437055ad.2; Mon, 26 Jun 2023 07:58:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687791488; x=1690383488; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to; bh=Hmh8wbv8PZygexgxnyH4qZ7wQNevvIr6Du0+ni35xCo=; b=qZnXvzcd2hJ3+aXJpt7yZh25TZGXjgiAXbclTWSXY9GxefrudhkGjH3O4YrdJ57bTv Q16QNuuMiSmjVZVWfCmJPzsrm2wxNiBOc/WphyZRbSz78TWdRHdlWkI77Le3b8DD0yfJ Qs+rAgQJeA3zJ/6NUimnZ1gRk6hDdm95g9rZCu234V2Cx2L477PuAInbgzpLUXokIxIJ ZiLhJVfFT5G4tJkvLxQMzGDZXAkDAa3ebu0IkFOyckaQLz1wqMBuO/b4goacTHrfbYp+ exZlcHyawxmP/068E+Q6swe+BWptcsP2Jicops8TTxYEtGwe8SNg1PIvB3xYSPLAvPkb h32Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687791488; x=1690383488; h=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=Hmh8wbv8PZygexgxnyH4qZ7wQNevvIr6Du0+ni35xCo=; b=Jn92gbupaQMLTvDymqHKOjFm1MkXCWe/CMPEVHlby88c4T+2klBbAebIMReKp41Mwa vw1CT85Gjz2FKUMPkRe/2vNNzEQ9+qg+Zry5Xnpt6WUsLISE4fgDsnYm1AsAf1RgXvLH Lpuu724kYz07F+J3gC9e3TauLTD4DSI/ZBQnpJrUIctN4gF1wWWixrznH3cEkullJENL Yx/5G69Qs+FfcAZldyKlVR0o/Eu0YY8QRnfy+RTMYFWf2dmJQDYtgk8tSiiO2kOXFVar sfQ+tixP217WUV9iDrPy36VC4M/guQo1rLTguVZqR41wysAPwVoI38yh4HaFXnE66JIe gk/g== X-Gm-Message-State: AC+VfDyV4mQKtFiIRpNjd+1x4xJ4Ur2c+LxE+IcMA1YvRVsbjRvTaM1D NhSQRhgsC8mGyzAWkDe6kG4= X-Google-Smtp-Source: ACHHUZ6+/UHdi5peXrr2q6q5paiSAe744S/gQ1FkDR6baMkvQ+7IrFOjVgV2aptlE+PekUaFm/3Yyg== X-Received: by 2002:a17:903:188:b0:1b2:4b28:793c with SMTP id z8-20020a170903018800b001b24b28793cmr9013547plg.29.1687791488320; Mon, 26 Jun 2023 07:58:08 -0700 (PDT) Received: from 377044c6c369.cse.ust.hk (191host097.mobilenet.cse.ust.hk. [143.89.191.97]) by smtp.gmail.com with ESMTPSA id x20-20020a170902821400b001b1a2bf5277sm4313303pln.39.2023.06.26.07.58.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Jun 2023 07:58:07 -0700 (PDT) From: Chengfeng Ye To: linus.walleij@linaro.org, brgl@bgdev.pl, andy@kernel.org Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, cyeaa@connect.ust.hk, Chengfeng Ye Subject: [PATCH v2 2/2] gpiolib: cdev: Fix &le->wait.lock deadlock issue Date: Mon, 26 Jun 2023 14:57:56 +0000 Message-Id: <20230626145756.30696-2-dg573847474@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20230626145756.30696-1-dg573847474@gmail.com> References: <20230626145756.30696-1-dg573847474@gmail.com> Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org The softirq lineevent_irq_thread() could deadlock on &le->wait.lock if it preempts lineevent_read_unlocked() which acquires the same lock but not disable irq. Fix the potential deadlock by spin_lock_irq(). Fixes: dea9c80ee672 ("gpiolib: rework the locking mechanism for lineevent kfifo") Signed-off-by: Chengfeng Ye --- drivers/gpio/gpiolib-cdev.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/gpio/gpiolib-cdev.c b/drivers/gpio/gpiolib-cdev.c index f768d46bdea7..a2c108f172f2 100644 --- a/drivers/gpio/gpiolib-cdev.c +++ b/drivers/gpio/gpiolib-cdev.c @@ -1858,28 +1858,28 @@ static ssize_t lineevent_read_unlocked(struct file *file, char __user *buf, return -EINVAL; do { - spin_lock(&le->wait.lock); + spin_lock_irq(&le->wait.lock); if (kfifo_is_empty(&le->events)) { if (bytes_read) { - spin_unlock(&le->wait.lock); + spin_unlock_irq(&le->wait.lock); return bytes_read; } if (file->f_flags & O_NONBLOCK) { - spin_unlock(&le->wait.lock); + spin_unlock_irq(&le->wait.lock); return -EAGAIN; } - ret = wait_event_interruptible_locked(le->wait, + ret = wait_event_interruptible_locked_irq(le->wait, !kfifo_is_empty(&le->events)); if (ret) { - spin_unlock(&le->wait.lock); + spin_unlock_irq(&le->wait.lock); return ret; } } ret = kfifo_out(&le->events, &ge, 1); - spin_unlock(&le->wait.lock); + spin_unlock_irq(&le->wait.lock); if (ret != 1) { /* * This should never happen - we were holding the lock