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x86/nmi: Fix nmi_handle() duration miscalculation

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[ Upstream commit f94c91f7ba3ba7de2bc8aa31be28e1abb22f849e ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Libing Zhou 2020-08-20 10:56:41 +08:00 committed by Greg Kroah-Hartman
parent b257bb437d
commit 200f13d0d9
1 changed files with 2 additions and 3 deletions
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5
arch/x86/kernel/nmi.c
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@ -106,7 +106,6 @@ 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)
@ -114,12 +113,12 @@ 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)