Re: OOPS in do_try_to_free_pages with VERY large software RAID array

[Kevin P. Fleming]

Martin J. Bligh wrote:
> At a wild guess (OK, I only looked for about 1 minute),
> md_status_read_proc is generating more than 4K of information, and overwriting
> the end of it's 4K page. Throw some debug in there, and get it to printk
> how much of the buffer it thinks it's using (just printk sz every time it
> changes it). If it's > 4K, convert it to the seq_file interface.
> 
> May not be it, but it seems likely given the unusual scale of what you're
> doing, and it's easy to check.
> 
> M.

I posted a patch to do exactly this last week to the Linux-RAID mailing list. If 
you check the archives you should find it. This problem also occurs if you use 
the device-mapper under 2.5.X, because it makes all 256 md minors appear in the 
tables and /proc/mdstat wants to tell you about all of them.