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Date: Tue, 11 Jun 2024 10:30:05 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: syzbot <syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, muchun.song@linux.dev,
 syzkaller-bugs@googlegroups.com, Vivek Kasireddy
 <vivek.kasireddy@intel.com>
Subject: Re: [syzbot] [mm?] general protection fault in
 dequeue_hugetlb_folio_nodemask (2)
Message-Id: <20240611103005.ae4170608bd15d63adee2492@linux-foundation.org>
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On Tue, 11 Jun 2024 03:34:25 -0700 syzbot <syzbot+569ed13f4054f271087b@syzkaller.appspotmail.com> wrote:

> Hello,
> 
> syzbot found the following issue on:

Thanks.

> Call Trace:
>  <TASK>
>  alloc_hugetlb_folio_nodemask+0xae/0x3f0 mm/hugetlb.c:2603
>  memfd_alloc_folio+0x15e/0x390 mm/memfd.c:75
>  memfd_pin_folios+0x1066/0x1720 mm/gup.c:3864
>  udmabuf_create+0x658/0x11c0 drivers/dma-buf/udmabuf.c:353
>  udmabuf_ioctl_create drivers/dma-buf/udmabuf.c:420 [inline]
>  udmabuf_ioctl+0x304/0x4f0 drivers/dma-buf/udmabuf.c:451
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:907 [inline]
>  __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f

I think we can pretty confidently point at the series "mm/gup:
Introduce memfd_pin_folios() for pinning memfd folios".  I'll drop the
v14 series.