This is a note to let you know that I've just added the patch titled
ACPI / APEI: Fix NMI notification handling
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
acpi-apei-fix-nmi-notification-handling.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a545715d2dae8d071c5b06af947b07ffa846b288 Mon Sep 17 00:00:00 2001
From: Prarit Bhargava <prarit@xxxxxxxxxx>
Date: Wed, 30 Nov 2016 08:19:39 -0500
Subject: ACPI / APEI: Fix NMI notification handling
From: Prarit Bhargava <prarit@xxxxxxxxxx>
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@xxxxxxxxxx>
Reviewed-by: Borislav Petkov <bp@xxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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;
Patches currently in stable-queue which might be from prarit@xxxxxxxxxx are
queue-4.4/acpi-apei-fix-nmi-notification-handling.patch
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