Received-SPF: pass (google.com: domain of linux-kernel+bounces-153923-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:40f1:3f00::1 as permitted sender) client-ip=2604:1380:40f1:3f00::1;
Precedence: bulk
MIME-Version: 1.0
References: <CAJg=8jyuSxDL6XvqEXY_66M20psRK2J53oBTP+fjV5xpW2-R6w@mail.gmail.com>
 <uekqafv4wx5axijnnfybnxixui3ruzy3mkxirflv7tb3ovrtbk@ounqurycykuv>
 <CAJg=8jzRT=oA9g6AGd1KmAY3GBkKkczj1rCqQ+pik5LmUQYd_A@mail.gmail.com>
 <7jhx44ynje54wfcq3bkaui5w6oox7ypd7cgg4u5zhue6rf5tok@nj6jaxppzq2b>
 <usubtr2bibcnwca3rk3ytbd2jbpvshgu44faujrrrcnidnrr25@ttdhvhrz34vs>
 <CAJg=8jyaV20PannVxVQrqasmo3RCTAjOWfmkdm3ehviMoc=V-w@mail.gmail.com> <4vyuejd7gikyjlbmcpmdcemplminhy27ltbodmq7nkjsozzod7@ttzgzxrjp63y>
In-Reply-To: <4vyuejd7gikyjlbmcpmdcemplminhy27ltbodmq7nkjsozzod7@ttzgzxrjp63y>
From: Marius Fleischer <fleischermarius@gmail.com>
Date: Mon, 22 Apr 2024 12:34:16 -0700
Message-ID: <CAJg=8jx3jVc-Z-z7=WJFhv1TjH8MW6oTQo69xCDhxc5aX6H_=g@mail.gmail.com>
Subject: Re: general protection fault in mas_empty_area_rev
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Andrew Morton <akpm@linux-foundation.org>, maple-tree@lists.infradead.org, 
	linux-kernel@vger.kernel.org, syzkaller@googlegroups.com, 
	harrisonmichaelgreen@gmail.com
Content-Type: text/plain; charset="UTF-8"

Hi Liam,

On Mon, 22 Apr 2024 at 11:53, Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
> * Marius Fleischer <fleischermarius@gmail.com> [240422 14:07]:
> > Hi Liam,
> >
> > On Mon, 22 Apr 2024 at 10:05, Liam R. Howlett <Liam.Howlett@oracle.com> wrote:
> > > * Liam R. Howlett <Liam.Howlett@oracle.com> [240422 11:25]:
> > > > * Marius Fleischer <fleischermarius@gmail.com> [240422 11:11]:
> > > > > Hi Liam,
> > > > >
> > > > > Thank you so much for the response!
> > > > >
> > > > > > >
> > > > > > > Crash log:
> > > > > > >
> > > > > > > general protection fault, probably for non-canonical address
> > > > > > > 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN NOPTI
> > > > > > >
> > > > > > > KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
> > > > > > >
> > > > > > > CPU: 0 PID: 79545 Comm: syz-executor.0 Not tainted 6.9.0-rc4-dirty #3
> > > > > >
> > > > > > This indicates that you built with your own patches.  Could you test an
> > > > > > unmodified 6.9.0-rc4 with your setup?
> > > > > >
> > > > >
> > > > > I'm very sorry for this oversight. I had applied the patches for another bug
> > > > > from this conversation
> > > > > (https://lore.kernel.org/all/20240404070702.2744-3-osalvador@suse.de/T/#m480f21ab850996395082d0faab7f624f45b83781)
> > > > > I will test the reproducer without these patches and get back to you!
> > > >
> > > > After testing with your config, I can see that those fixes are needed to
> > > > boot.
> > > >
> > > > I am going to try 6.9-rc5 with your configuration and see if I can
> > > > trigger the issue there.
> > > >
> > >
> > > The reproducer does not trigger for me with your configuration and
> > > reproducer.
> > >
> > > Does it still happen for you in 6.9-rc5?
> > >
> > You are right, indeed, I was not able to boot v6.9-rc4 without the fixes.
> >
> > I tested the reproducer on 6.9-rc5 (ed30a4a51bb196781c8058073ea720133a65596f)
> > and it still triggers the crash in my setup. How can I help you
> > further troubleshoot
> > this issue?
>
> Can you try the attached patch and see if that stops the crash?
>

I tested your patch against 6.9-rc5. It stops the crash.

Best,
Marius