Re: [syzbot] [mm?] possible deadlock in __unmap_hugepage_range

Re: [syzbot] [mm?] possible deadlock in __unmap_hugepage_range

[Andrew Morton]

On Fri, 26 Jan 2024 01:04:29 -0800 syzbot <syzbot+a1deb5533794ff31868e@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    8bf1262c53f5 Add linux-next specific files for 20240124
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1218a7abe80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=ff4b59a824278780
> dashboard link: https://syzkaller.appspot.com/bug?extid=a1deb5533794ff31868e
> compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=151a9cf7e80000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=164b70cfe80000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/7696d711072d/disk-8bf1262c.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/92cd47c28072/vmlinux-8bf1262c.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/add5c7493418/bzImage-8bf1262c.xz
> 
> The issue was bisected to:
> 
> commit 947b031634e7af3d265275c26ec17e2f96fdb5a1
> Author: Breno Leitao <leitao@debian.org>
> Date:   Wed Jan 17 17:10:57 2024 +0000
> 
>     mm/hugetlb: restore the reservation if needed

Thanks.  But moments after I moved this into mm.git's
mm-hotfixes-stable branch, in preparation for upstreaming.

I have fully dropped the patches titled

	mm/hugetlb: restore the reservation if needed
	selftests/mm: run_vmtests.sh: add hugetlb_madv_vs_map

Re: [syzbot] [mm?] possible deadlock in __unmap_hugepage_range

[Breno Leitao]

On Fri, Jan 26, 2024 at 01:25:40AM -0800, Andrew Morton wrote:
> On Fri, 26 Jan 2024 01:04:29 -0800 syzbot <syzbot+a1deb5533794ff31868e@syzkaller.appspotmail.com> wrote:
> 
> > Hello,
> > 
> > syzbot found the following issue on:
> > 
> > HEAD commit:    8bf1262c53f5 Add linux-next specific files for 20240124
> > git tree:       linux-next
> > console+strace: https://syzkaller.appspot.com/x/log.txt?x=1218a7abe80000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=ff4b59a824278780
> > dashboard link: https://syzkaller.appspot.com/bug?extid=a1deb5533794ff31868e
> > compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=151a9cf7e80000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=164b70cfe80000
> > 
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/7696d711072d/disk-8bf1262c.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/92cd47c28072/vmlinux-8bf1262c.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/add5c7493418/bzImage-8bf1262c.xz
> > 
> > The issue was bisected to:
> > 
> > commit 947b031634e7af3d265275c26ec17e2f96fdb5a1
> > Author: Breno Leitao <leitao@debian.org>
> > Date:   Wed Jan 17 17:10:57 2024 +0000
> > 
> >     mm/hugetlb: restore the reservation if needed
> 
> Thanks.  But moments after I moved this into mm.git's
> mm-hotfixes-stable branch, in preparation for upstreaming.
> 
> I have fully dropped the patches titled
> 
> 	mm/hugetlb: restore the reservation if needed
> 	selftests/mm: run_vmtests.sh: add hugetlb_madv_vs_map
> 

Thanks Andrew. Let me investigate it. I post as I find what's wrong.