* [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation
@ 2020-08-20 2:56 Libing Zhou
2020-08-31 7:02 ` Zhou, Libing (NSB - CN/Hangzhou)
2020-10-01 12:46 ` [tip: x86/misc] x86/nmi: Fix nmi_handle() " tip-bot2 for Libing Zhou
0 siblings, 2 replies; 3+ messages in thread
From: Libing Zhou @ 2020-08-20 2:56 UTC (permalink / raw)
To: peterz, tglx, mingo, bp, bp, x86; +Cc: linux-kernel, libing.zhou, hpa
In nmi_check_duration(), the 'whole_msecs' value get from
'action->max_duration' is wrong.
Fixes: 248ed51048c4 ("x86/nmi: Remove irq_work from the long duration NMI handler")
Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
---
v2:
Change solution as peterz@infradead.org suggested.
arch/x86/kernel/nmi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
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)
--
2.22.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* RE: [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation
2020-08-20 2:56 [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation Libing Zhou
@ 2020-08-31 7:02 ` Zhou, Libing (NSB - CN/Hangzhou)
2020-10-01 12:46 ` [tip: x86/misc] x86/nmi: Fix nmi_handle() " tip-bot2 for Libing Zhou
1 sibling, 0 replies; 3+ messages in thread
From: Zhou, Libing (NSB - CN/Hangzhou) @ 2020-08-31 7:02 UTC (permalink / raw)
To: peterz, tglx, mingo, bp, bp, x86; +Cc: linux-kernel, hpa
Hi,
Any comment on this?
-----Original Message-----
From: Libing Zhou <libing.zhou@nokia-sbell.com>
Sent: 2020年8月20日 10:57
To: peterz@infradead.org; tglx@linutronix.de; mingo@redhat.com; bp@alien8.de; bp@suse.de; x86@kernel.org
Cc: linux-kernel@vger.kernel.org; Zhou, Libing (NSB - CN/Hangzhou) <libing.zhou@nokia-sbell.com>; hpa@zytor.com
Subject: [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation
In nmi_check_duration(), the 'whole_msecs' value get from 'action->max_duration' is wrong.
Fixes: 248ed51048c4 ("x86/nmi: Remove irq_work from the long duration NMI handler")
Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
---
v2:
Change solution as peterz@infradead.org suggested.
arch/x86/kernel/nmi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
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)
--
2.22.0
^ permalink raw reply [flat|nested] 3+ messages in thread
* [tip: x86/misc] x86/nmi: Fix nmi_handle() duration miscalculation
2020-08-20 2:56 [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation Libing Zhou
2020-08-31 7:02 ` Zhou, Libing (NSB - CN/Hangzhou)
@ 2020-10-01 12:46 ` tip-bot2 for Libing Zhou
1 sibling, 0 replies; 3+ messages in thread
From: tip-bot2 for Libing Zhou @ 2020-10-01 12:46 UTC (permalink / raw)
To: linux-tip-commits
Cc: Peter Zijlstra (Intel),
Libing Zhou, Borislav Petkov, Changbin Du, x86, LKML
The following commit has been merged into the x86/misc branch of tip:
Commit-ID: f94c91f7ba3ba7de2bc8aa31be28e1abb22f849e
Gitweb: https://git.kernel.org/tip/f94c91f7ba3ba7de2bc8aa31be28e1abb22f849e
Author: Libing Zhou <libing.zhou@nokia-sbell.com>
AuthorDate: Thu, 20 Aug 2020 10:56:41 +08:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 01 Oct 2020 14:42:08 +02:00
x86/nmi: Fix nmi_handle() duration miscalculation
When nmi_check_duration() is checking the time an NMI handler took to
execute, the whole_msecs value used should be read from the @duration
argument, not from the ->max_duration, the latter being used to store
the current maximal duration.
[ bp: Rewrite commit message. ]
Fixes: 248ed51048c4 ("x86/nmi: Remove irq_work from the long duration NMI handler")
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Libing Zhou <libing.zhou@nokia-sbell.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Changbin Du <changbin.du@gmail.com>
Link: https://lkml.kernel.org/r/20200820025641.44075-1-libing.zhou@nokia-sbell.com
---
arch/x86/kernel/nmi.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c
index 4fc9954..4738166 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
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2020-08-20 2:56 [PATCH v2] x86/nmi: Fix nmi_handle duration miscalculation Libing Zhou
2020-08-31 7:02 ` Zhou, Libing (NSB - CN/Hangzhou)
2020-10-01 12:46 ` [tip: x86/misc] x86/nmi: Fix nmi_handle() " tip-bot2 for Libing Zhou
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