Re: [syzbot] [mm?] kernel BUG in sanity_check_pinned_pages

[syzbot <syzbot+1d335893772467199ab6@syzkaller.appspotmail.com>]

syzbot has found a reproducer for the following issue on:

HEAD commit:    9aa9b43d689e Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=1525330c580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=27f179c74d5c35cd
dashboard link: https://syzkaller.appspot.com/bug?extid=1d335893772467199ab6
compiler:       Debian clang version 20.1.6 (++20250514063057+1e4d39e07757-1~exp1~20250514183223.118), Debian LLD 20.1.6
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16d73370580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=160ef30c580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/974f3ac1c6a5/disk-9aa9b43d.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/a5b5075d317f/vmlinux-9aa9b43d.xz
kernel image: https://storage.googleapis.com/syzbot-assets/2f0ba7fec19b/Image-9aa9b43d.gz.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/76067befefec/mount_4.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=1549f6bc580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+1d335893772467199ab6@syzkaller.appspotmail.com

head: ffffffffffffffff 0000000000000000 00000000ffffffff 0000000000000200
page dumped because: VM_BUG_ON_PAGE(!PageAnonExclusive(&folio->page) && !PageAnonExclusive(page))
------------[ cut here ]------------
kernel BUG at mm/gup.c:71!
Internal error: Oops - BUG: 00000000f2000800 [#1]  SMP
Modules linked in:
CPU: 1 UID: 0 PID: 2171 Comm: kworker/u8:9 Not tainted 6.16.0-rc2-syzkaller-g9aa9b43d689e #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Workqueue: iou_exit io_ring_exit_work
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : sanity_check_pinned_pages+0x7cc/0x7d0 mm/gup.c:70
lr : sanity_check_pinned_pages+0x7cc/0x7d0 mm/gup.c:70
sp : ffff8000a03a7640
x29: ffff8000a03a7660 x28: dfff800000000000 x27: 1fffffbff8723000
x26: 05ffc00000020178 x25: 05ffc00000020178 x24: fffffdffc3918000
x23: fffffdffc3918000 x22: ffff8000a03a76e0 x21: 05ffc00000020178
x20: 0000000000000000 x19: ffff8000a03a76e0 x18: 00000000ffffffff
x17: 703e2d6f696c6f66 x16: ffff80008aecb65c x15: 0000000000000001
x14: 1fffe000337e14e2 x13: 0000000000000000 x12: 0000000000000000
x11: ffff6000337e14e3 x10: 0000000000ff0100 x9 : cc07ffb5a919f400
x8 : cc07ffb5a919f400 x7 : 0000000000000001 x6 : 0000000000000001
x5 : ffff8000a03a6d58 x4 : ffff80008f727060 x3 : ffff8000807bef2c
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000061
Call trace:
 sanity_check_pinned_pages+0x7cc/0x7d0 mm/gup.c:70 (P)
 unpin_user_page+0x80/0x10c mm/gup.c:192
 io_release_ubuf+0x84/0xf8 io_uring/rsrc.c:116
 io_buffer_unmap io_uring/rsrc.c:143 [inline]
 io_free_rsrc_node+0x250/0x57c io_uring/rsrc.c:516
 io_put_rsrc_node io_uring/rsrc.h:103 [inline]
 io_rsrc_data_free+0x148/0x298 io_uring/rsrc.c:200
 io_sqe_buffers_unregister+0x84/0xa0 io_uring/rsrc.c:610
 io_ring_ctx_free+0x48/0x480 io_uring/io_uring.c:2729
 io_ring_exit_work+0x764/0x7d8 io_uring/io_uring.c:2971
 process_one_work+0x7e8/0x155c kernel/workqueue.c:3238
 process_scheduled_works kernel/workqueue.c:3321 [inline]
 worker_thread+0x958/0xed8 kernel/workqueue.c:3402
 kthread+0x5fc/0x75c kernel/kthread.c:464
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:847
Code: b0052bc1 91008021 aa1703e0 97fff8ab (d4210000) 
---[ end trace 0000000000000000 ]---


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