Messages in this thread | | | From | Linus Torvalds <> | Date | Fri, 1 Jun 2012 21:58:50 -0700 | Subject | Re: WARNING: at mm/page-writeback.c:1990 __set_page_dirty_nobuffers+0x13a/0x170() |
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On Fri, Jun 1, 2012 at 9:40 PM, Hugh Dickins <hughd@google.com> wrote: > > Move the lock after the loop, I think you meant.
Well, I wasn't sure if anything inside the loop might need it. I don't *think* so, but at the same time, what protects "page_order(page)" (or, indeed PageBuddy()) from being stable while that loop content uses them?
I don't understand that code at all. It does that crazy iteration over page, and changes "page" in random ways, and then finishes up with a totally new "page" value that is some random thing that is *after* the end_page thing. WHAT?
The code makes no sense. It tests all those pages within the page-block, but then after it has done all those tests, it does the final
set_pageblock_migratetype(..) move_freepages_block(..)
using a page that is *beyond* the pageblock (and with the whole page_order() thing, who knows just how far beyond it?)
It looks entirely too much like random-monkey code to me.
Linus
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