Commit 67701ae9 authored by Jack F Vogel's avatar Jack F Vogel Committed by Linus Torvalds
Browse files

[PATCH] check nmi watchdog is broken



A bug against an xSeries system showed up recently noting that the
check_nmi_watchdog() test was failing.

I have been investigating it and discovered in both i386 and x86_64 the
recent change to the routine to use the cpu_callin_map has uncovered a
problem.  Prior to that change, on an SMP box, the test was trivally
passing because all cpu's were found to not yet be online, but now with the
callin_map they are discovered, it goes on to test the counter and they
have not yet begun to increment, so it announces a CPU is stuck and bails
out.

On all the systems I have access to test, the announcement of failure is
also bougs...  by the time you can login and check /proc/interrupts, the
NMI count is happily incrementing on all CPUs.  Its just that the test is
being done too early.

I have tried moving the call to the test around a bit, and it was always
too early.  I finally hit on this proposed solution, it delays the routine
via a late_initcall(), seems like the right solution to me.
Signed-off-by: default avatarAdrian Bunk <bunk@stusta.de>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent fd51f666
......@@ -1265,8 +1265,6 @@ int __init APIC_init_uniprocessor (void)
setup_local_APIC();
if (nmi_watchdog == NMI_LOCAL_APIC)
check_nmi_watchdog();
#ifdef CONFIG_X86_IO_APIC
if (smp_found_config)
if (!skip_ioapic_setup && nr_ioapics)
......
......@@ -2175,7 +2175,6 @@ static inline void check_timer(void)
disable_8259A_irq(0);
setup_nmi();
enable_8259A_irq(0);
check_nmi_watchdog();
}
return;
}
......@@ -2198,7 +2197,6 @@ static inline void check_timer(void)
add_pin_to_irq(0, 0, pin2);
if (nmi_watchdog == NMI_IO_APIC) {
setup_nmi();
check_nmi_watchdog();
}
return;
}
......
......@@ -102,20 +102,21 @@ int nmi_active;
(P4_CCCR_OVF_PMI0|P4_CCCR_THRESHOLD(15)|P4_CCCR_COMPLEMENT| \
P4_CCCR_COMPARE|P4_CCCR_REQUIRED|P4_CCCR_ESCR_SELECT(4)|P4_CCCR_ENABLE)
int __init check_nmi_watchdog (void)
static int __init check_nmi_watchdog(void)
{
unsigned int prev_nmi_count[NR_CPUS];
int cpu;
printk(KERN_INFO "testing NMI watchdog ... ");
if (nmi_watchdog == NMI_NONE)
return 0;
printk(KERN_INFO "Testing NMI watchdog ... ");
for (cpu = 0; cpu < NR_CPUS; cpu++)
prev_nmi_count[cpu] = per_cpu(irq_stat, cpu).__nmi_count;
local_irq_enable();
mdelay((10*1000)/nmi_hz); // wait 10 ticks
/* FIXME: Only boot CPU is online at this stage. Check CPUs
as they come up. */
for (cpu = 0; cpu < NR_CPUS; cpu++) {
#ifdef CONFIG_SMP
/* Check cpu_callin_map here because that is set
......@@ -139,6 +140,8 @@ int __init check_nmi_watchdog (void)
return 0;
}
/* This needs to happen later in boot so counters are working */
late_initcall(check_nmi_watchdog);
static int __init setup_nmi_watchdog(char *str)
{
......
......@@ -1089,9 +1089,6 @@ static void __init smp_boot_cpus(unsigned int max_cpus)
}
}
if (nmi_watchdog == NMI_LOCAL_APIC)
check_nmi_watchdog();
smpboot_setup_io_apic();
setup_boot_APIC_clock();
......
......@@ -1607,7 +1607,6 @@ static inline void check_timer(void)
disable_8259A_irq(0);
setup_nmi();
enable_8259A_irq(0);
check_nmi_watchdog();
}
return;
}
......@@ -1627,7 +1626,6 @@ static inline void check_timer(void)
nmi_watchdog_default();
if (nmi_watchdog == NMI_IO_APIC) {
setup_nmi();
check_nmi_watchdog();
}
return;
}
......
......@@ -112,17 +112,20 @@ static __init int cpu_has_lapic(void)
}
}
int __init check_nmi_watchdog (void)
static int __init check_nmi_watchdog (void)
{
int counts[NR_CPUS];
int cpu;
if (nmi_watchdog == NMI_NONE)
return 0;
if (nmi_watchdog == NMI_LOCAL_APIC && !cpu_has_lapic()) {
nmi_watchdog = NMI_NONE;
return -1;
}
printk(KERN_INFO "testing NMI watchdog ... ");
printk(KERN_INFO "Testing NMI watchdog ... ");
for (cpu = 0; cpu < NR_CPUS; cpu++)
counts[cpu] = cpu_pda[cpu].__nmi_count;
......@@ -148,6 +151,8 @@ int __init check_nmi_watchdog (void)
return 0;
}
/* Have this called later during boot so counters are updating */
late_initcall(check_nmi_watchdog);
int __init setup_nmi_watchdog(char *str)
{
......
......@@ -109,7 +109,6 @@ extern int APIC_init_uniprocessor (void);
extern void disable_APIC_timer(void);
extern void enable_APIC_timer(void);
extern int check_nmi_watchdog (void);
extern void enable_NMI_through_LVT0 (void * dummy);
extern unsigned int nmi_watchdog;
......
......@@ -99,7 +99,6 @@ extern void disable_APIC_timer(void);
extern void enable_APIC_timer(void);
extern void clustered_apic_check(void);
extern int check_nmi_watchdog(void);
extern void nmi_watchdog_default(void);
extern int setup_nmi_watchdog(char *);
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment