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ACPI / APEI: Fix NMI notification handling

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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 2383844d48 ("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
2383844d48 ("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: 2383844d48 (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>
This commit is contained in:
Prarit Bhargava 2016-11-30 08:19:39 -05:00 committed by Rafael J. Wysocki
parent e5517c2a5a
commit a545715d2d
1 changed files with 4 additions and 3 deletions
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7
drivers/acpi/apei/ghes.c
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@ -852,6 +852,8 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
if (ghes_read_estatus(ghes, 1)) {
ghes_clear_estatus(ghes);
continue;
} else {
ret = NMI_HANDLED;
}
sev = ghes_severity(ghes->estatus->error_severity);
@ -863,12 +865,11 @@ static int ghes_notify_nmi(unsigned int cmd, struct pt_regs *regs)
__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;