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 3466113AC4 for ; Mon, 26 Jun 2023 18:14:14 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A485BC433C9; Mon, 26 Jun 2023 18:14:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1687803254; bh=2CrKPW+w7p9J0l18Me6JQdySmzAHdzRir3nTzO0/6bc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=b1QLHG5AfXm5a+sBx4Mc4ahSh4YpOxv7SNw1jccKSM7Va0BFQeEgnHDBhvHKEFUH6 6nGOJ0dsiYkLnDsH42QbqkNGGaUHEQ+jZAsVSHJl/u8EVgMwpqAnkOdEZU7D7/vl/3 +maMsV7wS+9b5L5xfRLt4VN5EeHiZUPnnFF1Cuxk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Dheeraj Kumar Srivastava , "Borislav Petkov (AMD)" , Kishon Vijay Abraham I , Vasant Hegde , Cyrill Gorcunov , Thomas Gleixner , Sasha Levin Subject: [PATCH 4.14 25/26] x86/apic: Fix kernel panic when booting with intremap=off and x2apic_phys Date: Mon, 26 Jun 2023 20:11:27 +0200 Message-ID: <20230626180734.690915285@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230626180733.699092073@linuxfoundation.org> References: <20230626180733.699092073@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Dheeraj Kumar Srivastava [ Upstream commit 85d38d5810e285d5aec7fb5283107d1da70c12a9 ] When booting with "intremap=off" and "x2apic_phys" on the kernel command line, the physical x2APIC driver ends up being used even when x2APIC mode is disabled ("intremap=off" disables x2APIC mode). This happens because the first compound condition check in x2apic_phys_probe() is false due to x2apic_mode == 0 and so the following one returns true after default_acpi_madt_oem_check() having already selected the physical x2APIC driver. This results in the following panic: kernel BUG at arch/x86/kernel/apic/io_apic.c:2409! invalid opcode: 0000 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.4.0-rc2-ver4.1rc2 #2 Hardware name: Dell Inc. PowerEdge R6515/07PXPY, BIOS 2.3.6 07/06/2021 RIP: 0010:setup_IO_APIC+0x9c/0xaf0 Call Trace: ? native_read_msr apic_intr_mode_init x86_late_time_init start_kernel x86_64_start_reservations x86_64_start_kernel secondary_startup_64_no_verify which is: setup_IO_APIC: apic_printk(APIC_VERBOSE, "ENABLING IO-APIC IRQs\n"); for_each_ioapic(ioapic) BUG_ON(mp_irqdomain_create(ioapic)); Return 0 to denote that x2APIC has not been enabled when probing the physical x2APIC driver. [ bp: Massage commit message heavily. ] Fixes: 9ebd680bd029 ("x86, apic: Use probe routines to simplify apic selection") Signed-off-by: Dheeraj Kumar Srivastava Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Kishon Vijay Abraham I Reviewed-by: Vasant Hegde Reviewed-by: Cyrill Gorcunov Reviewed-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230616212236.1389-1-dheerajkumar.srivastava@amd.com Signed-off-by: Sasha Levin --- arch/x86/kernel/apic/x2apic_phys.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c index 98716a4be0a7c..fb9abdfc364d1 100644 --- a/arch/x86/kernel/apic/x2apic_phys.c +++ b/arch/x86/kernel/apic/x2apic_phys.c @@ -95,7 +95,10 @@ static void init_x2apic_ldr(void) static int x2apic_phys_probe(void) { - if (x2apic_mode && (x2apic_phys || x2apic_fadt_phys())) + if (!x2apic_mode) + return 0; + + if (x2apic_phys || x2apic_fadt_phys()) return 1; return apic == &apic_x2apic_phys; -- 2.39.2