Re: [PATCH] mm/arm: pgtable: remove young bit check for pte_valid_user

[Brian Ruley]

On Apr 13, Brian Ruley wrote:
> 
> In the meanwhile, I'll see if I can add some instrumentation to
> verify this is the bug we're seeing.

The instrumentation worked (used the same ring buffer approach to track
dcache flushes). Here's the output:

```
kernel: [48629.557043] SIGILL at b6b80ac0 cpu 1 pid 32663 linux_pte=8eff659f hw_pte=8eff6e7e young=1 exec=1
kernel: [48629.557157] dcache flush START   cpu0 pfn=8eff6 ts=48629557020154
kernel: [48629.557207] dcache flush FINISH  cpu0 pfn=8eff6 ts=48629557036154
kernel: [48629.557230] dcache flush SKIPPED cpu1 pfn=8eff6 ts=48629557020154
audisp-syslog: type=ANOM_ABEND msg=audit(1776154637.460:15): auid=4294967295 uid=0 gid=0 ses=4294967295 pid=32663 comm="journalctl" exe="/usr/bin/journalctl" sig=4 res=1 AUID="unset" UID="root" GID="root"
```

BR,
Brian