From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1674CC2D0E4 for ; Thu, 12 Nov 2020 20:47:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9BEA521D7F for ; Thu, 12 Nov 2020 20:47:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="N242L88X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727162AbgKLUrq (ORCPT ); Thu, 12 Nov 2020 15:47:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33276 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726621AbgKLUrq (ORCPT ); Thu, 12 Nov 2020 15:47:46 -0500 Received: from mail-qk1-x741.google.com (mail-qk1-x741.google.com [IPv6:2607:f8b0:4864:20::741]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 22B00C0613D1; Thu, 12 Nov 2020 12:47:46 -0800 (PST) Received: by mail-qk1-x741.google.com with SMTP id v143so6809682qkb.2; Thu, 12 Nov 2020 12:47:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=36FLese2veI3iWY1QIV+jskXlXxefI3GQpE+1eH4p2M=; b=N242L88XsM3GRxlJ2PrswON7oLbOaXDRPkFkUypxgYjX70C2zM4TZ4z24sFdgzA5wO AGb9xNXSszor6MsYuSNJDjb5UZbLxVDyNYmvpqHyIXF8jkwegXAW+Chhn/nyIxtCb3oU H+EXURpITkmZlqTUEBwnNrgANQE1shcem8X9KTHmNIJEBmSlW/zYHzq8xl44thxor6IU sb/C91xxIwysSeTGnith13BHsiyF2THFRKtg4pn1R3shTmpX0kY4V6xuM6EhN9dX0UeO oRUNk7rR4kBHi4VudSvjH1yRt3n/E8rGLJWguEH0kEdXoB/VEQmS98RdPH8/mgbPKfcX M+7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=36FLese2veI3iWY1QIV+jskXlXxefI3GQpE+1eH4p2M=; b=Mq3h1bDmwyfPuCzMGIPLjuFRgY98qTmVF9fTjO9wAM4ziwUzizNsW/dPRXh2tNT680 5mc/zDmFbsQfDXJ2c+u9D2T1QJ9mCdk+Jh58uOBpotPy8/Ht3hhfJd7NFEbFjgHd+nRJ zGQeNez+Mfvht1xDDcIFJya14EXYmJkqse3XfBoezIaq8RpMLl3QgoI1aOvqCK304ymS KEKK/7bLzhtwQRFoCpBKlLRjCH2MVF72B0MsAGOwK2NuovB/xPxzoG92b78mhIyXr2nt 0rvHku8uURijhe35LAJQkCkuzePwmkFPa3EXznjIKyo071TtzrisnUeLuWUUGqQp1sEG uCEg== X-Gm-Message-State: AOAM53042bnP7pMkI0VonKa8xCGoYuES1MeCG7vew2r+IrekKapeP/ks +ePfIe6UlQtVp6p53OQ3GgM= X-Google-Smtp-Source: ABdhPJywpb2aGtJbMUBTz7dHBirLYndXq9uNXazWC4ByK4FHtHoZyXJNI3QQNh4eAvU69x7oIlMddQ== X-Received: by 2002:ae9:ef02:: with SMTP id d2mr1760318qkg.68.1605214065166; Thu, 12 Nov 2020 12:47:45 -0800 (PST) Received: from localhost.localdomain ([198.52.185.246]) by smtp.gmail.com with ESMTPSA id f61sm5369419qtb.75.2020.11.12.12.47.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 12 Nov 2020 12:47:44 -0800 (PST) From: Sven Van Asbroeck X-Google-Original-From: Sven Van Asbroeck To: Jakub Kicinski , Bryan Whitehead , David S Miller Cc: Sven Van Asbroeck , Microchip Linux Driver Support , Andrew Lunn , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v1] lan743x: prevent entire kernel HANG on open, for some platforms Date: Thu, 12 Nov 2020 15:47:41 -0500 Message-Id: <20201112204741.12375-1-TheSven73@gmail.com> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Sven Van Asbroeck On arm imx6, when opening the chip's netdev, the whole Linux kernel intermittently hangs/freezes. This is caused by a bug in the driver code which tests if pcie interrupts are working correctly, using the software interrupt: 1. open: enable the software interrupt 2. open: tell the chip to assert the software interrupt 3. open: wait for flag 4. ISR: acknowledge s/w interrupt, set flag 5. open: notice flag, disable the s/w interrupt, continue Unfortunately the ISR only acknowledges the s/w interrupt, but does not disable it. This will re-trigger the ISR in a tight loop. On some (lucky) platforms, open proceeds to disable the s/w interrupt even while the ISR is 'spinning'. On arm imx6, the spinning ISR does not allow open to proceed, resulting in a hung Linux kernel. Fix minimally by disabling the s/w interrupt in the ISR, which will prevent it from spinning. This won't break anything because the s/w interrupt is used as a one-shot interrupt. Note that this is a minimal fix, overlooking many possible cleanups, e.g.: - lan743x_intr_software_isr() is completely redundant and reads INT_STS twice for no apparent reason - disabling the s/w interrupt in lan743x_intr_test_isr() is now redundant, but harmless - waiting on software_isr_flag can be converted from a sleeping poll loop to wait_event_timeout() Fixes: 23f0703c125b ("lan743x: Add main source files for new lan743x driver") Tested-by: Sven Van Asbroeck # arm imx6 lan7430 Signed-off-by: Sven Van Asbroeck --- Tree: git://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git # edbc21113bde To: Jakub Kicinski To: Bryan Whitehead To: "David S. Miller" Cc: Microchip Linux Driver Support Cc: Andrew Lunn Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org drivers/net/ethernet/microchip/lan743x_main.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/microchip/lan743x_main.c b/drivers/net/ethernet/microchip/lan743x_main.c index 065e10bc98f2..f4a09e0f3ec5 100644 --- a/drivers/net/ethernet/microchip/lan743x_main.c +++ b/drivers/net/ethernet/microchip/lan743x_main.c @@ -148,7 +148,8 @@ static void lan743x_intr_software_isr(void *context) int_sts = lan743x_csr_read(adapter, INT_STS); if (int_sts & INT_BIT_SW_GP_) { - lan743x_csr_write(adapter, INT_STS, INT_BIT_SW_GP_); + /* disable the interrupt to prevent repeated re-triggering */ + lan743x_csr_write(adapter, INT_EN_CLR, INT_BIT_SW_GP_); intr->software_isr_flag = 1; } } -- 2.17.1