From: David Hildenbrand <david@redhat.com>
To: syzbot <syzbot+3b220254df55d8ca8a61@syzkaller.appspotmail.com>,
Liam.Howlett@oracle.com, akpm@linux-foundation.org,
harry.yoo@oracle.com, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, lorenzo.stoakes@oracle.com, riel@surriel.com,
syzkaller-bugs@googlegroups.com, vbabka@suse.cz,
Jens Axboe <axboe@kernel.dk>,
Catalin Marinas <catalin.marinas@arm.com>
Subject: Re: [syzbot] [mm?] kernel BUG in try_to_unmap_one (2)
Date: Thu, 5 Jun 2025 08:27:42 +0200 [thread overview]
Message-ID: <fda7a3e3-1711-4f1b-a0bb-6a4369aa80ab@redhat.com> (raw)
In-Reply-To: <4fc2c008-2384-4d94-b1bf-f0a076585a4a@redhat.com>
On 05.06.25 08:11, David Hildenbrand wrote:
> On 05.06.25 07:38, syzbot wrote:
>> Hello,
>>
>> syzbot found the following issue on:
>>
>> HEAD commit: d7fa1af5b33e Merge branch 'for-next/core' into for-kernelci
>
> Hmmm, another very odd page-table mapping related problem on that tree
> found on arm64 only:
In this particular reproducer we seem to be having MADV_HUGEPAGE and
io_uring_setup() be racing with MADV_HWPOISON, MADV_PAGEOUT and
io_uring_register(IORING_REGISTER_BUFFERS).
I assume the issue is related to MADV_HWPOISON, MADV_PAGEOUT and
io_uring_register racing, only. I suspect MADV_HWPOISON is trying to
split a THP, while MADV_PAGEOUT tries paging it out.
IORING_REGISTER_BUFFERS ends up in
io_sqe_buffers_register->io_sqe_buffer_register where we GUP-fast and
try coalescing buffers.
And something about THPs is not particularly happy :)
--
Cheers,
David / dhildenb
next prev parent reply other threads:[~2025-06-05 6:27 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-06-05 5:38 syzbot
2025-06-05 6:11 ` David Hildenbrand
2025-06-05 6:27 ` David Hildenbrand [this message]
2025-06-05 6:37 ` David Hildenbrand
2025-06-05 7:18 ` Jinjiang Tu
2025-06-06 7:56 ` David Hildenbrand
2025-06-07 1:29 ` Jinjiang Tu
2025-06-09 8:35 ` Miaohe Lin
2025-06-05 7:37 ` Jinjiang Tu
2025-06-06 7:40 ` David Hildenbrand
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