| From a545715d2dae8d071c5b06af947b07ffa846b288 Mon Sep 17 00:00:00 2001 |
| From: Prarit Bhargava <prarit@redhat.com> |
| Date: Wed, 30 Nov 2016 08:19:39 -0500 |
| Subject: ACPI / APEI: Fix NMI notification handling |
| |
| From: Prarit Bhargava <prarit@redhat.com> |
| |
| commit a545715d2dae8d071c5b06af947b07ffa846b288 upstream. |
| |
| When removing and adding cpu 0 on a system with GHES NMI the following stack |
| trace is seen when re-adding the cpu: |
| |
| WARNING: CPU: 0 PID: 0 at arch/x86/kernel/apic/apic.c:1349 setup_local_APIC+ |
| Modules linked in: nfsv3 rpcsec_gss_krb5 nfsv4 nfs fscache coretemp intel_ra |
| CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.9.0-rc6+ #2 |
| Call Trace: |
| dump_stack+0x63/0x8e |
| __warn+0xd1/0xf0 |
| warn_slowpath_null+0x1d/0x20 |
| setup_local_APIC+0x275/0x370 |
| apic_ap_setup+0xe/0x20 |
| start_secondary+0x48/0x180 |
| set_init_arg+0x55/0x55 |
| early_idt_handler_array+0x120/0x120 |
| x86_64_start_reservations+0x2a/0x2c |
| x86_64_start_kernel+0x13d/0x14c |
| |
| During the cpu bringup, wakeup_cpu_via_init_nmi() is called and issues an |
| NMI on CPU 0. The GHES NMI handler, ghes_notify_nmi() runs the |
| ghes_proc_irq_work work queue which ends up setting IRQ_WORK_VECTOR |
| (0xf6). The "faulty" IR line set at arch/x86/kernel/apic/apic.c:1349 is also |
| 0xf6 (specifically APIC IRR for irqs 255 to 224 is 0x400000) which confirms |
| that something has set the IRQ_WORK_VECTOR line prior to the APIC being |
| initialized. |
| |
| Commit 2383844d4850 ("GHES: Elliminate double-loop in the NMI handler") |
| incorrectly modified the behavior such that the handler returns |
| NMI_HANDLED only if an error was processed, and incorrectly runs the ghes |
| work queue for every NMI. |
| |
| This patch modifies the ghes_proc_irq_work() to run as it did prior to |
| 2383844d4850 ("GHES: Elliminate double-loop in the NMI handler") by |
| properly returning NMI_HANDLED and only calling the work queue if |
| NMI_HANDLED has been set. |
| |
| Fixes: 2383844d4850 (GHES: Elliminate double-loop in the NMI handler) |
| Signed-off-by: Prarit Bhargava <prarit@redhat.com> |
| Reviewed-by: Borislav Petkov <bp@suse.de> |
| Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/acpi/apei/ghes.c | 7 ++++--- |
| 1 file changed, 4 insertions(+), 3 deletions(-) |
| |
| --- a/drivers/acpi/apei/ghes.c |
| +++ b/drivers/acpi/apei/ghes.c |
| @@ -847,6 +847,8 @@ static int ghes_notify_nmi(unsigned int |
| if (ghes_read_estatus(ghes, 1)) { |
| ghes_clear_estatus(ghes); |
| continue; |
| + } else { |
| + ret = NMI_HANDLED; |
| } |
| |
| sev = ghes_severity(ghes->estatus->error_severity); |
| @@ -858,12 +860,11 @@ static int ghes_notify_nmi(unsigned int |
| |
| __process_error(ghes); |
| ghes_clear_estatus(ghes); |
| - |
| - ret = NMI_HANDLED; |
| } |
| |
| #ifdef CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG |
| - irq_work_queue(&ghes_proc_irq_work); |
| + if (ret == NMI_HANDLED) |
| + irq_work_queue(&ghes_proc_irq_work); |
| #endif |
| atomic_dec(&ghes_in_nmi); |
| return ret; |
