Re: shmem_getpage_gfp VM_BUG_ON triggered. [3.7rc2]

From: Hugh Dickins
Date: Thu Oct 25 2012 - 17:28:52 EST


On Thu, 25 Oct 2012, Dave Jones wrote:
> On Wed, Oct 24, 2012 at 09:36:27PM -0700, Hugh Dickins wrote:
>
> > Clutching at straws, I expect this is entirely irrelevant, but:
> > there isn't a warning on line 1151 of mm/shmem.c in 3.7.0-rc2 nor
> > in current linux.git; rather, there's a VM_BUG_ON on line 1149.
> >
> > So you've inserted a couple of lines for some reason (more useful
> > trinity behaviour, perhaps)?
>
> detritus from the recent mpol_to_str bug that I was chasing.
> Shouldn't be relevant...
>
> > And have some config option I'm
> > unfamiliar with, that mutates a BUG_ON or VM_BUG_ON into a warning?
>
> Yes, I do have this..
>
> -#define VM_BUG_ON(cond) BUG_ON(cond)
> +#define VM_BUG_ON(cond) WARN_ON(cond)
>
> because I got tired of things not going over my usb serial port when I hit them
> a while ago. BUG_ON is pretty unfriendly to bug finding.

Makes sense, thanks for the reassurance.

Hugh
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/