---
id: CVE-2026-98821
title: 'block: reject polled dio with user integrity metadata'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  block: reject polled dio with user integrity metadata

  IOCB_HAS_METADATA leaves iocb->private as a uio_meta, while
  iocb_bio_iopoll() expects a bio. Since 2729a60bbfb9, …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 <
    c97ef13ad96be0e08af38dfa2ed40cded0b53e1b
  - >-
    Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 <
    dd33c03cefccdfcb223e9e6262643d64f8c1ae20
  - >-
    Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 <
    2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e
  - Linux 17ecefc9fdd8c554e0d03e5a990daef19f930add
  - Linux >= 6.16.8 < 6.17
  - Linux 6.17
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:49:13.154Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98821'
references:
  - url: 'https://git.kernel.org/stable/c/c97ef13ad96be0e08af38dfa2ed40cded0b53e1b'
  - url: 'https://git.kernel.org/stable/c/dd33c03cefccdfcb223e9e6262643d64f8c1ae20'
  - url: 'https://git.kernel.org/stable/c/2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e'
tags:
  - cve.org
ingestedAt: '2026-10-18T16:47:32.474Z'
---

## Overview

In the Linux kernel, the following vulnerability has been resolved:

block: reject polled dio with user integrity metadata

IOCB_HAS_METADATA leaves iocb->private as a uio_meta, while
iocb_bio_iopoll() expects a bio. Since 2729a60bbfb9, metadata I/O
always uses __blkdev_direct_IO(), which never publishes the bio for
polling, so IOPOLL calls bio_poll() on the uio_meta.

Reproducer: io_uring IOPOLL plus a PI attribute on an integrity device
(scsi_debug dif=1 dix=1). KASAN reports:

  Oops: general protection fault, probably for non-canonical
  address 0xdffffc0000000004
  KASAN: null-ptr-deref in range
  [0x0000000000000020-0x0000000000000027]
  RIP: 0010:bio_poll+0x9d/0x4b0
  Call Trace:
   iocb_bio_iopoll+0x5b/0x80
   io_uring_classic_poll+0xf3/0x140
   io_do_iopoll+0x4e3/0xc00
   io_iopoll_check+0x275/0x560
   __do_sys_io_uring_enter+0x2e5/0x720

Return -EOPNOTSUPP when HIPRI is combined with user metadata.

## Affected

- `Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 < c97ef13ad96be0e08af38dfa2ed40cded0b53e1b`
- `Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 < dd33c03cefccdfcb223e9e6262643d64f8c1ae20`
- `Linux >= 2729a60bbfb9215997f25372ebe9b7964f038296 < 2a42e6fe1293f2e2d579c9fe5bbab056dd8b880e`
- `Linux 17ecefc9fdd8c554e0d03e5a990daef19f930add`
- `Linux >= 6.16.8 < 6.17`
- `Linux 6.17`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.