Re: [PATCH] fix off-by-one in dump_childnos()

2017-04-16 21:34 GMT+03:00 Dave Jones <[email protected]>:
> On Sun, Apr 16, 2017 at 09:29:14PM +0300, Tommi Rantala wrote:
>  > Fixes a segfault:
>  >
>  >   ## pids: (60 active)
>  >   0-7: 0 0 0 0 0 0 0 0
>  >   8-15: 0 0 0 0 0 0 0 0
>  >   16-23: 0 0 0 0 0 0 0 0
>  >   24-31: 0 0 0 0 0 0 0 0
>  >   32-39: 0 11081 11082 11083 11084 11085 11086 11087
>  >   40-47: 11088 11089 11090 11091 11093 11094 11095 11096
>  >   48-55: 11097 11098 11099 11100 11101 11102 0 0
>  >   Segmentation fault
>
> Applied.  If you're seeing that though, that's indicative of a bigger
> problem (that we corrupted the pid table, or lost track of a child proc.).

Yea, I believe it was just about to exit anyways after the debug output.

> I've not seen that happen in about a year, does it happen often for you?

I was testing trinity in some minimal busybox & qemu environment, and
saw it a few times.
Now that I try it again, cannot reproduce the segfault anymore...

All the trinity processes have read-write access to the pids[] array?
So any one of them could corrupt the memory...?

-Tommi