panic: wm_page_unwire

[Dmitry Sivachenko]

> On 19 июня 2015 г., at 22:57, Dmitry Sivachenko <trtrmitya at gmail.com> wrote:
> 
> Hello,
> 
> got this panic today on my 10.1-STABLE #0 r279956  box:
> 
> <Screen Shot 2015-06-19 at 22.52.57.png>


Well, I tracked this down a bit.  Rather easy way to panic -stable box (mine is r279956), but I can't reliably reproduce this.

It happens when there is a process running which mmap()+mlock() some file, and while it is running this file is modified on disk
(not rm+mv, but open the same file, truncate and write some other data into it).

After process exits, system will panic with high probability.

So far I got 2 cases:

1) run process which mlock()'s a file;  modify that file;  stop process and system panics
2) run process which mlock()'s a file;  modify that file;  stop process [no panic so far];  modify that file again and system panics.

Panic message is the same: panic: vm_page_unwire: page <xxxx>'s wire count is zero