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From: Mel Gorman <mgorman@techsingularity.net>
To: lkp@lists.01.org
Subject: Re: [mm/page_alloc] 2bd8eec68f: BUG:sleeping_function_called_from_invalid_context_at_mm/gup.c
Date: Wed, 06 Jul 2022 15:53:24 +0100
Message-ID: <20220706145324.GH27531@techsingularity.net>
In-Reply-To: <YsWbWsN2qPbWsNWZ@xsang-OptiPlex-9020>
List-Id: <oe-lkp.lists.linux.dev>

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On Wed, Jul 06, 2022 at 10:25:30PM +0800, Oliver Sang wrote:
> hi, Mel Gorman,
> =

> On Wed, Jul 06, 2022 at 10:55:35AM +0100, Mel Gorman wrote:
> > On Tue, Jul 05, 2022 at 09:51:25PM +0800, Oliver Sang wrote:
> > > Hi Andrew Morton,
> > > =

> > > On Sun, Jul 03, 2022 at 01:22:09PM -0700, Andrew Morton wrote:
> > > > On Sun, 3 Jul 2022 17:44:30 +0800 kernel test robot <oliver.sang@=
intel.com> wrote:
> > > > =

> > > > > FYI, we noticed the following commit (built with gcc-11):
> > > > > =

> > > > > commit: 2bd8eec68f740608db5ea58ecff06965228764cb ("[PATCH 7/7] mm=
/page_alloc: Replace local_lock with normal spinlock")
> > > > > url: https://github.com/intel-lab-lkp/linux/commits/Mel-Gorman/Dr=
ain-remote-per-cpu-directly/20220613-230139
> > > > > base: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux=
.git b13baccc3850ca8b8cccbf8ed9912dbaa0fdf7f3
> > > > > patch link: https://lore.kernel.org/lkml/20220613125622.18628-8-m=
gorman(a)techsingularity.net
> > > > > =

> > > > =

> > > > Did this test include the followup patch
> > > > mm-page_alloc-replace-local_lock-with-normal-spinlock-fix.patch?
> > > =

> > > no, we just fetched original patch set and test upon it.
> > > =

> > > now we applied the patch you pointed to us upon 2bd8eec68f and found =
the issue
> > > still exist.
> > > (attached dmesg FYI)
> > > =

> > =

> > Thanks Oliver.
> > =

> > The trace is odd in that it hits in GUP when the page allocator is no
> > longer active and the context is a syscall. First, is this definitely
> > the first patch the problem occurs?
> > =

> > Second, it's possible for IRQs to be enabled and an IRQ delivered before
> > preemption is enabled. It's not clear why that would be a problem other
> > than lacking symmetry or how it could result in the reported BUG but
> > might as well rule it out. This is build tested only
> =

> do you want us test below patch?
> if so, should we apply it upon the patch
> "mm/page_alloc: Replace local_lock with normal spinlock"
> or
> "mm/page_alloc: replace local_lock with normal spinlock -fix"?
> =


On top of "mm/page_alloc: replace local_lock with normal spinlock -fix"
please. The -fix patch is cosmetic but it'd still be better to test on
top.

Thanks!

-- =

Mel Gorman
SUSE Labs
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