Re: [PATCH] mm/vmalloc: warn only once when vmalloc detect invalid gfp flags

Vishal Moola (Oracle)
2025-11-18T01:06:09Z

On Tue, Nov 18, 2025 at 01:51:23AM +0100, David Heidelberg wrote:
> On 18/11/2025 01:34, Vishal Moola (Oracle) wrote:
> > On Tue, Nov 18, 2025 at 01:05:57AM +0100, David Heidelberg via B4 Relay wrote:
> > > From: David Heidelberg <david@ixit.cz>
> > >
> > > Without WARN_ONCE, the logs get spammed immediately after the boot,
> > > on devices as OnePlus 6T (Snapdragon 845).
> >
> > Do you have any snippets of the logs? There'll be a particularly helpful
> > section that says "Unexpected gfp:"...
>
> I didn't save it, thou I'll run the kernel with all logs again tomorrow,
> what I remember it was "__GFP_ACCOUNT" in unexpected section.

Gotcha. That's particular flag has been added to the whitelist as of
today. Hopefully there are no others.

> >
> > > Fixes: 7179b2256315 ("mm/vmalloc: warn on invalid vmalloc gfp flags")
> >
> > For some context, this patch begins enforcing the gfp flags passed into
> > vmalloc(). If the logs are getting spammed, that means the device is
> > calling vmalloc() with some unsupported gfp flag, many many times.
>
> Yes, it was full dmesg buffer just after the boot and I think ongoing.
>
> >
> > > Signed-off-by: David Heidelberg <david@ixit.cz>
> > > ---
> > > I'm not 100% sure this is the right solution, but having WARN_ONCE or
> > > rate limited warnings here helps a lot on devices as OnePlus 6 (sdm845).
> >
> > Can you check if it still happens on today's mm-new?
> > I just sent a new version earlier today that also masks off
> > __GFP_ACCOUNT, and had an iteration earlier that added
> > __GFP_HARDWALL.
>
> I can try tomorrow, any chance it'll bubble into next-20251118?

I'm not sure, Andrew should know?

> Thank you
> David
>
> --
> David Heidelberg
>