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authorLibing Zhou <[email protected]>2020-08-20 10:56:41 +0800
committerBorislav Petkov <[email protected]>2020-10-01 14:42:08 +0200
commitf94c91f7ba3ba7de2bc8aa31be28e1abb22f849e (patch)
treeaa1048ce5484a96d123b071ae55113055381f98a
parentea4e3bef4c94d5b5d8e790f37b48b7641172bcf5 (diff)
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) <[email protected]> Signed-off-by: Libing Zhou <[email protected]> Signed-off-by: Borislav Petkov <[email protected]> Cc: Changbin Du <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
-rw-r--r--arch/x86/kernel/nmi.c5
1 files 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)