dm: fix NULL pointer dereference in __dm_suspend()

Description

In the Linux kernel, the following vulnerability has been resolved: dm: fix NULL pointer dereference in __dm_suspend() There is a race condition between dm device suspend and table load that can lead to null pointer dereference. The issue occurs when suspend is invoked before table load completes: BUG: kernel NULL pointer dereference, address: 0000000000000054 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 6798 Comm: dmsetup Not tainted 6.6.0-g7e52f5f0ca9b #62 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.1-2.fc37 04/01/2014 RIP: 0010:blk_mq_wait_quiesce_done+0x0/0x50 Call Trace: <TASK> blk_mq_quiesce_queue+0x2c/0x50 dm_stop_queue+0xd/0x20 __dm_suspend+0x130/0x330 dm_suspend+0x11a/0x180 dev_suspend+0x27e/0x560 ctl_ioctl+0x4cf/0x850 dm_ctl_ioctl+0xd/0x20 vfs_ioctl+0x1d/0x50 __se_sys_ioctl+0x9b/0xc0 __x64_sys_ioctl+0x19/0x30 x64_sys_call+0x2c4a/0x4620 do_syscall_64+0x9e/0x1b0 The issue can be triggered as below: T1 T2 dm_suspend table_load __dm_suspend dm_setup_md_queue dm_mq_init_request_queue blk_mq_init_allocated_queue => q->mq_ops = set->ops; (1) dm_stop_queue / dm_wait_for_completion => q->tag_set NULL pointer! (2) => q->tag_set = set; (3) Fix this by checking if a valid table (map) exists before performing request-based suspend and waiting for target I/O. When map is NULL, skip these table-dependent suspend steps. Even when map is NULL, no I/O can reach any target because there is no table loaded; I/O submitted in this state will fail early in the DM layer. Skipping the table-dependent suspend logic in this case is safe and avoids NULL pointer dereferences.

Timeline

Scores

No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Deferred.

EPSS (exploitation in 30 days)

0.23% · top 86% of all CVEs (10 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.

Affected products

• Linux · Linux

  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 9dc43ea6a20ff83fe9a5fe4be47ae0fbf2409b98
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 30f95b7eda5966b81cb221bd569c0f095a068cf6
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < a0e54bd8d7ea79127fe9920df3ae36f85e79ac7c
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < a802901b75e13cc306f1b7ab0f062135c8034e9e
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 846cafc4725ca727d94f9c4b5f789c1a7c8fb6fe
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 19ca4528666990be376ac3eb6fe667b03db5324d
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 331c2dd8ca8bad1a3ac10cce847ffb76158eece4
  • affected c4576aed8d85d808cd6443bda58393d525207d01 – < 8d33a030c566e1f105cd5bf27f37940b6367f3be

• Linux · Linux

  • affected 5.0
  • unaffected < 5.0
  • unaffected 5.4.301 – ≤ 5.4.*
  • unaffected 5.10.246 – ≤ 5.10.*
  • unaffected 5.15.195 – ≤ 5.15.*
  • unaffected 6.1.156 – ≤ 6.1.*
  • unaffected 6.6.112 – ≤ 6.6.*
  • unaffected 6.12.53 – ≤ 6.12.*
  • unaffected 6.17.3 – ≤ 6.17.*
  • unaffected 6.18 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2025-124949 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2025-40134](https://cveledger.app/badge/CVE-2025-40134.svg)](https://cveledger.app/cve/CVE-2025-40134)

Record last updated 5 Nov 2026, 21:23 UTC.