From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226/oaTazT8Mz1acJKpMXQN8y9SrugW1H85hIjpXVTkopG3huh6EuHke5L9SheWO3gur3F2x ARC-Seal: i=1; a=rsa-sha256; t=1519218700; cv=none; d=google.com; s=arc-20160816; b=vrO06T7sNuwBDdrZlGfQ+ReGfm3hpR+n7oV4/eatS7886cPQyvZNw0RyL8oPf0pZSY 0m5FwlgQ4SNk6zBaK/zXpGi9i+6dcg9pG1aeKkSSjZ+SxcJg96S3JbGdKS+7trCDezvH UtvKihZWOKYluLLH4+HXWXOZ8qeOZ5ziZOZ813e9K2bV6vrrKOCWfN/to3ENsZMKJdtZ jVKrAa2Bo6ebdGCXxj9Va+cnDS+dQq6mkhg/CPHdp6XBD8oXGrGslwbNEE4nydMboW9E R6AUHyY2sdwHJB6bfT1qtSz2poyky569SoRP6k5VkTKYnrnN7JoJIBxoQsqUA2ATW1HS QpSQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=1RzssPTA5Tcsfw+vpzbz4NENjigZ4vyYAWDAqxgU5b0=; b=QdBLoA6hDuvrxzSxKwnUa8nXiwIR7suPzeWH1ifaSnzRNSYUuvnhxeuOLWxrY1IGMY vmV89EO8TNgYk4H2BgU+mZWAEz0yYykHfuM4HG0oRIpLIbH4tkiHPC9AQkb2r7+8S5aw lHfGCqCaDR0mXfwmtljYobialAwT+Ujc6WA/+sgW30+jYXJduUyRlfYKUy2AtQBFTajl 1q9brkd3Ta3Z+pbl3VHEOVA+AU3fxY+OooPzT+t/iIYSinQSWYduCIG2DUTI+hANnqZx CuThOR8beagbwGKVibjUMuCDjR2/tQ+h955clPkjWu8A9ikAVsHHfPwhLVUqEUH1x6dP SVXw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Masayoshi Mizuma , Thomas Gleixner , Linus Torvalds , Peter Zijlstra , yasu.isimatu@gmail.com, Ingo Molnar Subject: [PATCH 4.15 098/163] x86/smpboot: Fix uncore_pci_remove() indexing bug when hot-removing a physical CPU Date: Wed, 21 Feb 2018 13:48:47 +0100 Message-Id: <20180221124535.713836865@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180221124529.931834518@linuxfoundation.org> References: <20180221124529.931834518@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1593016267461386549?= X-GMAIL-MSGID: =?utf-8?q?1593016267461386549?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Masayoshi Mizuma commit 295cc7eb314eb3321fb6d67ca6f7305f5c50d10f upstream. When a physical CPU is hot-removed, the following warning messages are shown while the uncore device is removed in uncore_pci_remove(): WARNING: CPU: 120 PID: 5 at arch/x86/events/intel/uncore.c:988 uncore_pci_remove+0xf1/0x110 ... CPU: 120 PID: 5 Comm: kworker/u1024:0 Not tainted 4.15.0-rc8 #1 Workqueue: kacpi_hotplug acpi_hotplug_work_fn ... Call Trace: pci_device_remove+0x36/0xb0 device_release_driver_internal+0x145/0x210 pci_stop_bus_device+0x76/0xa0 pci_stop_root_bus+0x44/0x60 acpi_pci_root_remove+0x1f/0x80 acpi_bus_trim+0x54/0x90 acpi_bus_trim+0x2e/0x90 acpi_device_hotplug+0x2bc/0x4b0 acpi_hotplug_work_fn+0x1a/0x30 process_one_work+0x141/0x340 worker_thread+0x47/0x3e0 kthread+0xf5/0x130 When uncore_pci_remove() runs, it tries to get the package ID to clear the value of uncore_extra_pci_dev[].dev[] by using topology_phys_to_logical_pkg(). The warning messesages are shown because topology_phys_to_logical_pkg() returns -1. arch/x86/events/intel/uncore.c: static void uncore_pci_remove(struct pci_dev *pdev) { ... phys_id = uncore_pcibus_to_physid(pdev->bus); ... pkg = topology_phys_to_logical_pkg(phys_id); // returns -1 for (i = 0; i < UNCORE_EXTRA_PCI_DEV_MAX; i++) { if (uncore_extra_pci_dev[pkg].dev[i] == pdev) { uncore_extra_pci_dev[pkg].dev[i] = NULL; break; } } WARN_ON_ONCE(i >= UNCORE_EXTRA_PCI_DEV_MAX); // <=========== HERE!! topology_phys_to_logical_pkg() tries to find cpuinfo_x86->phys_proc_id that matches the phys_pkg argument. arch/x86/kernel/smpboot.c: int topology_phys_to_logical_pkg(unsigned int phys_pkg) { int cpu; for_each_possible_cpu(cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); if (c->initialized && c->phys_proc_id == phys_pkg) return c->logical_proc_id; } return -1; } However, the phys_proc_id was already set to 0 by remove_siblinginfo() when the CPU was offlined. So, topology_phys_to_logical_pkg() cannot find the correct logical_proc_id and always returns -1. As the result, uncore_pci_remove() calls WARN_ON_ONCE() and the warning messages are shown. What is worse is that the bogus 'pkg' index results in two bugs: - We dereference uncore_extra_pci_dev[] with a negative index - We fail to clean up a stale pointer in uncore_extra_pci_dev[][] To fix these bugs, remove the clearing of ->phys_proc_id from remove_siblinginfo(). This should not cause any problems, because ->phys_proc_id is not used after it is hot-removed and it is re-set while hot-adding. Signed-off-by: Masayoshi Mizuma Acked-by: Thomas Gleixner Cc: Linus Torvalds Cc: Peter Zijlstra Cc: yasu.isimatu@gmail.com Cc: Fixes: 30bb9811856f ("x86/topology: Avoid wasting 128k for package id array") Link: http://lkml.kernel.org/r/ed738d54-0f01-b38b-b794-c31dc118c207@gmail.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/smpboot.c | 1 - 1 file changed, 1 deletion(-) --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1431,7 +1431,6 @@ static void remove_siblinginfo(int cpu) cpumask_clear(cpu_llc_shared_mask(cpu)); cpumask_clear(topology_sibling_cpumask(cpu)); cpumask_clear(topology_core_cpumask(cpu)); - c->phys_proc_id = 0; c->cpu_core_id = 0; cpumask_clear_cpu(cpu, cpu_sibling_setup_mask); recompute_smt_state();