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x86, mce: Do not call del_timer_sync() in IRQ context

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del_timer_sync() can cause a deadlock when called in interrupt context.
It is used with on_each_cpu() in some parts for sysfs files like bank*,
check_interval, cmci_disabled and ignore_ce.

However, use of on_each_cpu() results in calling the function passed
as the argument in interrupt context. This causes a flood of nested
warnings from del_timer_sync() (it runs on each CPU) caused even by a
simple file access like:

$ echo 300 > /sys/devices/system/machinecheck/machinecheck0/check_interval

Fortunately, these MCE-specific files are rarely used and AFAIK only few
MCE geeks experience this warning.

To remove the warning, move timer deletion outside of the interrupt
context.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
This commit is contained in:
Hidetoshi Seto 2011-06-17 04:40:36 -04:00 committed by Borislav Petkov
parent b6fd41e29d
commit 9aaef96f61
1 changed files with 14 additions and 6 deletions
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20
arch/x86/kernel/cpu/mcheck/mce.c
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@ -1140,6 +1140,15 @@ static void mce_start_timer(unsigned long data)
add_timer_on(t, smp_processor_id());
}
/* Must not be called in IRQ context where del_timer_sync() can deadlock */
static void mce_timer_delete_all(void)
{
int cpu;
for_each_online_cpu(cpu)
del_timer_sync(&per_cpu(mce_timer, cpu));
}
static void mce_do_trigger(struct work_struct *work)
{
call_usermodehelper(mce_helper, mce_helper_argv, NULL, UMH_NO_WAIT);
@ -1750,7 +1759,6 @@ static struct syscore_ops mce_syscore_ops = {
static void mce_cpu_restart(void *data)
{
del_timer_sync(&__get_cpu_var(mce_timer));
if (!mce_available(__this_cpu_ptr(&cpu_info)))
return;
__mcheck_cpu_init_generic();
@ -1760,16 +1768,15 @@ static void mce_cpu_restart(void *data)
/* Reinit MCEs after user configuration changes */
static void mce_restart(void)
{
mce_timer_delete_all();
on_each_cpu(mce_cpu_restart, NULL, 1);
}
/* Toggle features for corrected errors */
static void mce_disable_ce(void *all)
static void mce_disable_cmci(void *data)
{
if (!mce_available(__this_cpu_ptr(&cpu_info)))
return;
if (all)
del_timer_sync(&__get_cpu_var(mce_timer));
cmci_clear();
}
@ -1852,7 +1859,8 @@ static ssize_t set_ignore_ce(struct sys_device *s,
if (mce_ignore_ce ^ !!new) {
if (new) {
/* disable ce features */
on_each_cpu(mce_disable_ce, (void *)1, 1);
mce_timer_delete_all();
on_each_cpu(mce_disable_cmci, NULL, 1);
mce_ignore_ce = 1;
} else {
/* enable ce features */
@ -1875,7 +1883,7 @@ static ssize_t set_cmci_disabled(struct sys_device *s,
if (mce_cmci_disabled ^ !!new) {
if (new) {
/* disable cmci */
on_each_cpu(mce_disable_ce, NULL, 1);
on_each_cpu(mce_disable_cmci, NULL, 1);
mce_cmci_disabled = 1;
} else {
/* enable cmci */