From patchwork Tue Apr 28 21:13:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 214061 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=-9.9 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 BACDEC83004 for ; Tue, 28 Apr 2020 21:16:21 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 999EA206D6 for ; Tue, 28 Apr 2020 21:16:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="jBJu27+X" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726284AbgD1VQV (ORCPT ); Tue, 28 Apr 2020 17:16:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41086 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726689AbgD1VOU (ORCPT ); Tue, 28 Apr 2020 17:14:20 -0400 Received: from mail-pj1-x1042.google.com (mail-pj1-x1042.google.com [IPv6:2607:f8b0:4864:20::1042]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0C8A0C035495 for ; Tue, 28 Apr 2020 14:14:20 -0700 (PDT) Received: by mail-pj1-x1042.google.com with SMTP id y6so51090pjc.4 for ; Tue, 28 Apr 2020 14:14:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=krkKzlTv0evl7XtOBkWytpIaTxy+LxvUFfaqcuSVgrw=; b=jBJu27+X8D4yb2SJa0NENEq+yawHvCLl+udLKszJlfSZ5PVvIKoPqAvpvqME6MW9Mj qtD10jrVnoJisHmxdd2orvAtNEb08FdDeHufUZ6AIp0gEc/tKDo9VwzsZGvXCXUpkg1M G5IqiMT138ZbVoT57BPyqAsumzgYR5TeUCKng= 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=krkKzlTv0evl7XtOBkWytpIaTxy+LxvUFfaqcuSVgrw=; b=XJFa2rJ40064o0c+js1f9MbZlLYcXjZZnNwGnoALEGkFsHI3V0+HzoBv/FIdWqm+sX i32gcpunu3B5inlX1KkmdqFkMjpQO4z+jy3MOxKkaqwSRdcs1cQ1CmJ025RtbqLnOsrW sCZfFws8nA39PWSX7VGN7ic8OlbydmbPrvg/QD5VVEeR08ljuYK+w8M4hJHb1rMrrw7l N6E7SZCESuksO87eBTx/P9q6JhI9VgHL/GQ8+/Fde+dfhXCZCBMbTvJ96HH5ezgVQY70 qCF6a9r17ibH6TkLxOOtTHzyxQdeNjVJFDVKVUniwG78+wfPbdGNCbUs4dX4NsnorvLJ Ia0Q== X-Gm-Message-State: AGi0PubSJUv2K1HByYRCgB7whzEYMYj7d4lw42k1kJBL1Zp6Sr26GjNO TzFEh8Khn32io1QyiwKzahDmIg== X-Google-Smtp-Source: APiQypJr4LN15nTjffPKEvXDknvrivQ2C51b5dr29r1bWEMRSzhey9PsKy/AkanMbmobrgXqkvk/qQ== X-Received: by 2002:a17:902:8f90:: with SMTP id z16mr14622246plo.216.1588108459461; Tue, 28 Apr 2020 14:14:19 -0700 (PDT) Received: from tictac2.mtv.corp.google.com ([2620:15c:202:1:24fa:e766:52c9:e3b2]) by smtp.gmail.com with ESMTPSA id 18sm2988202pjf.30.2020.04.28.14.14.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Apr 2020 14:14:19 -0700 (PDT) From: Douglas Anderson To: jason.wessel@windriver.com, daniel.thompson@linaro.org, gregkh@linuxfoundation.org Cc: agross@kernel.org, kgdb-bugreport@lists.sourceforge.net, catalin.marinas@arm.com, linux-serial@vger.kernel.org, sumit.garg@linaro.org, corbet@lwn.net, mingo@redhat.com, will@kernel.org, hpa@zytor.com, tglx@linutronix.de, frowand.list@gmail.com, bp@alien8.de, bjorn.andersson@linaro.org, jslaby@suse.com, Douglas Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v3 01/11] kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb Date: Tue, 28 Apr 2020 14:13:41 -0700 Message-Id: <20200428141218.v3.1.Ied2b058357152ebcc8bf68edd6f20a11d98d7d4e@changeid> X-Mailer: git-send-email 2.26.2.303.gf8c07b1a785-goog In-Reply-To: <20200428211351.85055-1-dianders@chromium.org> References: <20200428211351.85055-1-dianders@chromium.org> MIME-Version: 1.0 Sender: linux-serial-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org In commit 81eaadcae81b ("kgdboc: disable the console lock when in kgdb") we avoided the WARN_CONSOLE_UNLOCKED() yell when we were in kgdboc. That still works fine, but it turns out that we get a similar yell when using other I/O drivers. One example is the "I/O driver" for the kgdb test suite (kgdbts). When I enabled that I again got the same yells. Even though "kgdbts" doesn't actually interact with the user over the console, using it still causes kgdb to print to the consoles. That trips the same warning: con_is_visible+0x60/0x68 con_scroll+0x110/0x1b8 lf+0x4c/0xc8 vt_console_print+0x1b8/0x348 vkdb_printf+0x320/0x89c kdb_printf+0x68/0x90 kdb_main_loop+0x190/0x860 kdb_stub+0x2cc/0x3ec kgdb_cpu_enter+0x268/0x744 kgdb_handle_exception+0x1a4/0x200 kgdb_compiled_brk_fn+0x34/0x44 brk_handler+0x7c/0xb8 do_debug_exception+0x1b4/0x228 Let's increment/decrement the "ignore_console_lock_warning" variable all the time when we enter the debugger. This will allow us to later revert commit 81eaadcae81b ("kgdboc: disable the console lock when in kgdb"). Signed-off-by: Douglas Anderson Reviewed-by: Greg Kroah-Hartman Reviewed-by: Daniel Thompson --- Changes in v3: None Changes in v2: - ("kgdb: Disable WARN_CONSOLE_UNLOCKED for all kgdb") new for v2. kernel/debug/debug_core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 2b7c9b67931d..950dc667c823 100644 --- a/kernel/debug/debug_core.c +++ b/kernel/debug/debug_core.c @@ -668,6 +668,8 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) goto kgdb_restore; + atomic_inc(&ignore_console_lock_warning); + /* Call the I/O driver's pre_exception routine */ if (dbg_io_ops->pre_exception) dbg_io_ops->pre_exception(); @@ -740,6 +742,8 @@ static int kgdb_cpu_enter(struct kgdb_state *ks, struct pt_regs *regs, if (dbg_io_ops->post_exception) dbg_io_ops->post_exception(); + atomic_dec(&ignore_console_lock_warning); + if (!kgdb_single_step) { raw_spin_unlock(&dbg_slave_lock); /* Wait till all the CPUs have quit from the debugger. */