In addition to what Joshua said (which is correct and the likely cause
- permissive mode automatically adds the permission to the AVC after
the first denial to avoid flooding the logs with repeated identical
denials), other possible issues you might encounter include:
1) The kernel ratelimits audit messages by default, which can suppress
denials if too many occur in a short period of time.  In our kernel
trees, we have a patch to disable the rateilmiting for development to
ensure we do not miss any denials during board bringup.  This is not
an issue once auditd is running.

2) Userspace code may take different paths based on what access is
granted, and therefore you might see different denials in permissive
vs enforcing.  Typically this shows up when a userspace process tries
to search a directory that isn't accessible in policy; if in
permissive, you'll see denials for the directory and all file within
it, whereas in enforcing you won't get past the initial search denial
on the directory.

However, for the most part, they should be identical.

On Tue, Nov 19, 2013 at 4:53 AM, Jaejyn Shin <[email protected]> wrote:
> Hi SEAndroid
>
> A denial log is printed during Enforcing-mode but it is not printed during
> permissive-mode.
>
> To check it in detail, I inserted printk at the end of avc_audit function of
> avc.c.
>
> 551         audited = requested & avd->auditallow;
> 552     if (likely(!audited))
> 553         return 0;
> 554     printk(KERN_ERR "jaejyn call slow_avc_audit\n"); //jaejyn.shin
> 555     return slow_avc_audit(ssid, tsid, tclass,
> 556         requested, audited, denied,
> 557         a, flags);
> 558 }
>
> The 554 line was also printed during Enforcing-mode but it is not printed
> during permissive-mode.
>
> The policies of Enforcing and Permissive are exactly same in the same image?
> Or is there any difference ?
>
> Thank you
> Best regards

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