On Mon, Oct 06, 2014 at 02:10:23PM -0700, Andy Lutomirski wrote:
> On 10/02/2014 10:28 PM, tip-bot for Wei Huang wrote:
> > msr_fail:
> > printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
> > - printk(KERN_ERR "Failed to access perfctr msr (MSR %x is %Lx)\n", reg, val_new);
> > + printk(boot_cpu_has(X86_FEATURE_HYPERVISOR) ? KERN_INFO : KERN_ERR
> > + "Failed to access perfctr msr (MSR %x is %Lx)\n", reg, val_new);
> >
>
> This is bogus. String concatenation doesn't work like that.
>
> Try "%sFailed...", boot_cpu_has(X86_FEATURE_HYPERVISOR) ? KERN_ERR :
> KERN_INFO), etc.
Haha, indeed. The hypervisor message is empty in this case. Wei, test
this much? ;-)
---
Subject: perf: Fix bogus kernel printk
Andy spotted the fail in what was intended as a conditional printk
level.
Fixes: cc6cd47e7395 ("perf/x86: Tone down kernel messages when the PMU check fails in a virtual environment")
Reported-by: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
arch/x86/kernel/cpu/perf_event.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/x86/kernel/cpu/perf_event.c
+++ b/arch/x86/kernel/cpu/perf_event.c
@@ -243,8 +243,9 @@ static bool check_hw_exists(void)
msr_fail:
printk(KERN_CONT "Broken PMU hardware detected, using software events only.\n");
- printk(boot_cpu_has(X86_FEATURE_HYPERVISOR) ? KERN_INFO : KERN_ERR
- "Failed to access perfctr msr (MSR %x is %Lx)\n", reg, val_new);
+ printk("%sFailed to access perfctr msr (MSR %x is %Lx)\n",
+ boot_cpu_has(X86_FEATURE_HYPERVISOR) ? KERN_INFO : KERN_ERR,
+ reg, val_new);
return false;
}
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