* [PATCH] x86/nmi: Fix nmi_handle duration miscalculation
@ 2020-08-17 9:04 Libing Zhou
2020-08-19 8:06 ` peterz
0 siblings, 1 reply; 3+ messages in thread
From: Libing Zhou @ 2020-08-17 9:04 UTC (permalink / raw)
To: tglx, mingo, bp, bp, x86; +Cc: linux-kernel, libing.zhou, hpa
In nmi_check_duration(), the 'whole_msecs' value should
get from 'duration' to reflect actual time duration,
but not 'action->max_duration'.
Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
---
arch/x86/kernel/nmi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 4fc9954a9560..c51ee659e520 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -102,7 +102,7 @@ fs_initcall(nmi_warning_debugfs);
static void nmi_check_duration(struct nmiaction *action, u64 duration)
{
- u64 whole_msecs = READ_ONCE(action->max_duration);
+ u64 whole_msecs = duration;
int remainder_ns, decimal_msecs;
if (duration < nmi_longest_ns || duration < action->max_duration)
--
2.22.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] x86/nmi: Fix nmi_handle duration miscalculation
2020-08-17 9:04 [PATCH] x86/nmi: Fix nmi_handle duration miscalculation Libing Zhou
@ 2020-08-19 8:06 ` peterz
2020-08-20 2:31 ` Zhou, Libing (NSB - CN/Hangzhou)
0 siblings, 1 reply; 3+ messages in thread
From: peterz @ 2020-08-19 8:06 UTC (permalink / raw)
To: Libing Zhou; +Cc: tglx, mingo, bp, bp, x86, linux-kernel, hpa
On Mon, Aug 17, 2020 at 05:04:41PM +0800, Libing Zhou wrote:
> In nmi_check_duration(), the 'whole_msecs' value should
> get from 'duration' to reflect actual time duration,
> but not 'action->max_duration'.
Fixes: 248ed51048c4 ("x86/nmi: Remove irq_work from the long duration NMI handler")
> Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
> ---
> arch/x86/kernel/nmi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
> index 4fc9954a9560..c51ee659e520 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -102,7 +102,7 @@ fs_initcall(nmi_warning_debugfs);
>
> static void nmi_check_duration(struct nmiaction *action, u64 duration)
> {
> - u64 whole_msecs = READ_ONCE(action->max_duration);
> + u64 whole_msecs = duration;
> int remainder_ns, decimal_msecs;
>
> if (duration < nmi_longest_ns || duration < action->max_duration)
The, IMO, saner solution is:
---
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 4fc9954a9560..47381666d6a5 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -102,7 +102,6 @@ fs_initcall(nmi_warning_debugfs);
static void nmi_check_duration(struct nmiaction *action, u64 duration)
{
- u64 whole_msecs = READ_ONCE(action->max_duration);
int remainder_ns, decimal_msecs;
if (duration < nmi_longest_ns || duration < action->max_duration)
@@ -110,12 +109,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
action->max_duration = duration;
- remainder_ns = do_div(whole_msecs, (1000 * 1000));
+ remainder_ns = do_div(duration, (1000 * 1000));
decimal_msecs = remainder_ns / 1000;
printk_ratelimited(KERN_INFO
"INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
- action->handler, whole_msecs, decimal_msecs);
+ action->handler, duration, decimal_msecs);
}
static int nmi_handle(unsigned int type, struct pt_regs *regs)
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH] x86/nmi: Fix nmi_handle duration miscalculation
2020-08-19 8:06 ` peterz
@ 2020-08-20 2:31 ` Zhou, Libing (NSB - CN/Hangzhou)
0 siblings, 0 replies; 3+ messages in thread
From: Zhou, Libing (NSB - CN/Hangzhou) @ 2020-08-20 2:31 UTC (permalink / raw)
To: peterz; +Cc: tglx, mingo, bp, bp, x86, linux-kernel, hpa
Thanks for your comments, I will recommit patch soon.
-----Original Message-----
From: peterz@infradead.org <peterz@infradead.org>
Sent: 2020年8月19日 16:07
To: Zhou, Libing (NSB - CN/Hangzhou) <libing.zhou@nokia-sbell.com>
Cc: tglx@linutronix.de; mingo@redhat.com; bp@alien8.de; bp@suse.de; x86@kernel.org; linux-kernel@vger.kernel.org; hpa@zytor.com
Subject: Re: [PATCH] x86/nmi: Fix nmi_handle duration miscalculation
On Mon, Aug 17, 2020 at 05:04:41PM +0800, Libing Zhou wrote:
> In nmi_check_duration(), the 'whole_msecs' value should get from
> 'duration' to reflect actual time duration, but not
> 'action->max_duration'.
Fixes: 248ed51048c4 ("x86/nmi: Remove irq_work from the long duration NMI handler")
> Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
> ---
> arch/x86/kernel/nmi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index
> 4fc9954a9560..c51ee659e520 100644
> --- a/arch/x86/kernel/nmi.c
> +++ b/arch/x86/kernel/nmi.c
> @@ -102,7 +102,7 @@ fs_initcall(nmi_warning_debugfs);
>
> static void nmi_check_duration(struct nmiaction *action, u64
> duration) {
> - u64 whole_msecs = READ_ONCE(action->max_duration);
> + u64 whole_msecs = duration;
> int remainder_ns, decimal_msecs;
>
> if (duration < nmi_longest_ns || duration < action->max_duration)
The, IMO, saner solution is:
---
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 4fc9954a9560..47381666d6a5 100644
--- a/arch/x86/kernel/nmi.c
+++ b/arch/x86/kernel/nmi.c
@@ -102,7 +102,6 @@ fs_initcall(nmi_warning_debugfs);
static void nmi_check_duration(struct nmiaction *action, u64 duration) {
- u64 whole_msecs = READ_ONCE(action->max_duration);
int remainder_ns, decimal_msecs;
if (duration < nmi_longest_ns || duration < action->max_duration) @@ -110,12 +109,12 @@ static void nmi_check_duration(struct nmiaction *action, u64 duration)
action->max_duration = duration;
- remainder_ns = do_div(whole_msecs, (1000 * 1000));
+ remainder_ns = do_div(duration, (1000 * 1000));
decimal_msecs = remainder_ns / 1000;
printk_ratelimited(KERN_INFO
"INFO: NMI handler (%ps) took too long to run: %lld.%03d msecs\n",
- action->handler, whole_msecs, decimal_msecs);
+ action->handler, duration, decimal_msecs);
}
static int nmi_handle(unsigned int type, struct pt_regs *regs)
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-08-20 2:46 UTC | newest]
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2020-08-17 9:04 [PATCH] x86/nmi: Fix nmi_handle duration miscalculation Libing Zhou
2020-08-19 8:06 ` peterz
2020-08-20 2:31 ` Zhou, Libing (NSB - CN/Hangzhou)
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