Re: [LKP] [ima] 8eb613c0b8: stress-ng.icache.ops_per_sec -84.2% regression

[Mimi Zohar]

Hi Xing,

On Wed, 2020-06-10 at 11:21 +0800, Xing Zhengjun wrote:
> Hi Mimi,
> 
>      Do you have time to take a look at this? we noticed a 3.7% 
> regression of boot-time.dhcp and a 84.2% regression of 
> stress-ng.icache.ops_per_sec. Thanks.
> 
> On 6/3/2020 5:11 PM, kernel test robot wrote:
> > Greeting,
> > 
> > FYI, we noticed a 3.7% regression of boot-time.dhcp due to commit:
> > 
> > 
> > commit: 8eb613c0b8f19627ba1846dcf78bb2c85edbe8dd ("ima: verify mprotect change is consistent with mmap policy")
> > https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master
> > 
> > in testcase: stress-ng
> > on test machine: 96 threads Intel(R) Xeon(R) Gold 6252 CPU @ 2.10GHz with 192G memory
> > with following parameters:
> > 
> > 	nr_threads: 100%
> > 	disk: 1HDD
> > 	testtime: 30s
> > 	class: cpu-cache
> > 	cpufreq_governor: performance
> > 	ucode: 0x500002c

Does the following change resolve it?

diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index c44414a7f82e..78e1dfc8a3f2 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -426,7 +426,8 @@ int ima_file_mprotect(struct vm_area_struct *vma, unsigned long prot)
 	int pcr;
 
 	/* Is mprotect making an mmap'ed file executable? */
-	if (!vma->vm_file || !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
+	if (!(ima_policy_flag & IMA_APPRAISE) || !vma->vm_file ||
+	    !(prot & PROT_EXEC) || (vma->vm_flags & VM_EXEC))
 		return 0;
 
 	security_task_getsecid(current, &secid);