Messages in this thread | | | Date | Mon, 14 Feb 2011 23:24:21 +0100 | From | Johannes Weiner <> | Subject | Re: [mmotm] BUG: Bad page state in process khugepaged ? |
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On Fri, Feb 11, 2011 at 11:49:06AM +0100, Andrea Arcangeli wrote: > On Thu, Feb 10, 2011 at 11:02:50PM -0800, Hugh Dickins wrote: > > There is a separate little issue here, Andrea. > > > > Although we went to some trouble for bad_page() to take the page out > > of circulation yet let the system continue, your VM_BUG_ON(!PageBuddy) > > inside __ClearPageBuddy(page), from two callsites in bad_page(), is > > turning it into a fatal error when CONFIG_DEBUG_VM. > > I see what you mean. Of course it is only a problem after bad_page > already triggered.... but then it trigger an BUG_ON instead of only a > bad_page. > > > You could that only MM developers switch CONFIG_DEBUG_VM=y, and they > > would like bad_page() to be fatal; maybe, but if so we should do that > > as an intentional patch, rather than as an unexpected side-effect ;) > > Fedora kernels are built with CONFIG_DEBUG_VM, all my kernels runs > with CONFIG_DEBUG_VM too, so we want it to be as "production" as > possible, and we don't want DEBUG_VM to decrease any reliability (only > to increase it of course).
Are you sure?
$ grep DEBUG_VM /boot/config-* /boot/config-2.6.35.10-74.fc14.x86_64:# CONFIG_DEBUG_VM is not set /boot/config-2.6.35.6-45.fc14.x86_64:# CONFIG_DEBUG_VM is not set
Only the one from the kernel-debug package has it set on this F14.
Hannes
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