From: Libing Zhou libing.zhou@nokia-sbell.com
[ 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 --- 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 d7c5e44b26f73..091752c3a19e2 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)