FKIE_CVE-2026-90186

Vulnerability from fkie_nvd - Published: 2026-09-17 17:17 - Updated: 2026-09-17 17:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: null_blk: reject per-device queue resize for shared tag set When shared_tags is enabled, null_setup_tagset() makes the device use the global tag_set, whose driver_data stays NULL. null_map_queues() therefore falls back to the module-wide g_submit_queues/g_poll_queues instead of any per-device value. Resizing submit_queues or poll_queues via configfs on such a device calls blk_mq_update_nr_hw_queues() on the shared set, shrinking set->nr_hw_queues. __blk_mq_realloc_hw_ctxs() only grows the q->queue_hw_ctx[] allocation, so on shrink it merely exits and NULLs the now-excess hctx slots. null_map_queues(), however, keeps mapping CPUs with the unchanged g_submit_queues/g_poll_queues, so mq_map[] ends up pointing at those NULLed hctx slots. blk_mq_map_swqueue() then dereferences the NULL hctx (hctx->cpumask), crashing the kernel: [ 460.218374] KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f] [ 460.219003] CPU: 24 UID: 0 PID: 1492 Comm: sh Not tainted 7.2.0-rc2+ #67 PREEMPT(full) [ 460.219792] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014 [ 460.220452] RIP: 0010:blk_mq_map_swqueue+0x4db/0x1430 ...... [ 460.228977] Call Trace: [ 460.229175] <TASK> [ 460.229354] blk_mq_update_nr_hw_queues+0xd49/0x11c0 [ 460.229779] ? __pfx_blk_mq_update_nr_hw_queues+0x10/0x10 [ 460.230200] nullb_update_nr_hw_queues+0x1a9/0x370 [null_blk] [ 460.230694] nullb_device_submit_queues_store+0xd9/0x170 [null_blk] [ 460.231190] ? __pfx_nullb_device_submit_queues_store+0x10/0x10 [null_blk] [ 460.231776] ? configfs_write_iter+0x35c/0x4e0 [ 460.232122] configfs_write_iter+0x286/0x4e0 [ 460.232460] vfs_write+0x52d/0xd00 [ 460.232779] ? __x64_sys_openat+0x108/0x1d0 [ 460.233106] ? __pfx_vfs_write+0x10/0x10 [ 460.233413] ? fdget_pos+0x1cf/0x4c0 [ 460.233745] ? fput_close+0x133/0x190 [ 460.234038] ? __pfx_expand_files+0x10/0x10 [ 460.234368] ksys_write+0xfc/0x1d0 Reproducer: modprobe null_blk shared_tags=1 submit_queues=64 poll_queues=1 mkdir /sys/kernel/config/nullb/dev echo 1 > /sys/kernel/config/nullb/dev/power echo 1 > /sys/kernel/config/nullb/dev/submit_queues A per-device resize of a shared tag set is meaningless anyway, so reject it with -EINVAL in nullb_update_nr_hw_queues() when the device is bound to the global tag_set.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/1cdfe2fa62b48728a9b436fbbd3dbe4c11593e24
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/3e35ad503386a2e8a0e0460530dcbf421c79f6f2
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9c7bae099ddc92676ad1b7e29dd6c089e5f6196c
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/baff300541a0012907cdde349728739fe16176d7
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/f609f7bf9ce8c2fc427705c4a9f623a281239d06
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/fcd53f3e8b758c79c3f2420d28a2a1dce6fda61a
Impacted products
Vendor Product Version
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{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/null_blk/main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "9c7bae099ddc92676ad1b7e29dd6c089e5f6196c",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            },
            {
              "lessThan": "fcd53f3e8b758c79c3f2420d28a2a1dce6fda61a",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            },
            {
              "lessThan": "f609f7bf9ce8c2fc427705c4a9f623a281239d06",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            },
            {
              "lessThan": "3e35ad503386a2e8a0e0460530dcbf421c79f6f2",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            },
            {
              "lessThan": "baff300541a0012907cdde349728739fe16176d7",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            },
            {
              "lessThan": "1cdfe2fa62b48728a9b436fbbd3dbe4c11593e24",
              "status": "affected",
              "version": "45919fbfe1c487c17ea1d198534339a5e8abeae3",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/null_blk/main.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.5"
            },
            {
              "lessThan": "5.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.188",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.157",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.110",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.52",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.6",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3-rc1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: reject per-device queue resize for shared tag set\n\nWhen shared_tags is enabled, null_setup_tagset() makes the device use the\nglobal tag_set, whose driver_data stays NULL. null_map_queues() therefore\nfalls back to the module-wide g_submit_queues/g_poll_queues instead of any\nper-device value.\n\nResizing submit_queues or poll_queues via configfs on such a device calls\nblk_mq_update_nr_hw_queues() on the shared set, shrinking\nset-\u003enr_hw_queues.  __blk_mq_realloc_hw_ctxs() only grows the\nq-\u003equeue_hw_ctx[] allocation, so on shrink it merely exits and NULLs the\nnow-excess hctx slots. null_map_queues(), however, keeps mapping CPUs with\nthe unchanged g_submit_queues/g_poll_queues, so mq_map[] ends up pointing\nat those NULLed hctx slots. blk_mq_map_swqueue() then dereferences the NULL\nhctx (hctx-\u003ecpumask), crashing the kernel:\n\n[  460.218374] KASAN: null-ptr-deref in range [0x0000000000000098-0x000000000000009f]\n[  460.219003] CPU: 24 UID: 0 PID: 1492 Comm: sh Not tainted 7.2.0-rc2+ #67 PREEMPT(full)\n[  460.219792] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.17.0-4.fc41 04/01/2014\n[  460.220452] RIP: 0010:blk_mq_map_swqueue+0x4db/0x1430\n......\n[  460.228977] Call Trace:\n[  460.229175]  \u003cTASK\u003e\n[  460.229354]  blk_mq_update_nr_hw_queues+0xd49/0x11c0\n[  460.229779]  ? __pfx_blk_mq_update_nr_hw_queues+0x10/0x10\n[  460.230200]  nullb_update_nr_hw_queues+0x1a9/0x370 [null_blk]\n[  460.230694]  nullb_device_submit_queues_store+0xd9/0x170 [null_blk]\n[  460.231190]  ? __pfx_nullb_device_submit_queues_store+0x10/0x10 [null_blk]\n[  460.231776]  ? configfs_write_iter+0x35c/0x4e0\n[  460.232122]  configfs_write_iter+0x286/0x4e0\n[  460.232460]  vfs_write+0x52d/0xd00\n[  460.232779]  ? __x64_sys_openat+0x108/0x1d0\n[  460.233106]  ? __pfx_vfs_write+0x10/0x10\n[  460.233413]  ? fdget_pos+0x1cf/0x4c0\n[  460.233745]  ? fput_close+0x133/0x190\n[  460.234038]  ? __pfx_expand_files+0x10/0x10\n[  460.234368]  ksys_write+0xfc/0x1d0\n\nReproducer:\nmodprobe null_blk shared_tags=1 submit_queues=64 poll_queues=1\nmkdir /sys/kernel/config/nullb/dev\necho 1 \u003e /sys/kernel/config/nullb/dev/power\necho 1 \u003e /sys/kernel/config/nullb/dev/submit_queues\n\nA per-device resize of a shared tag set is meaningless anyway, so reject it\nwith -EINVAL in nullb_update_nr_hw_queues() when the device is bound to the\nglobal tag_set."
    }
  ],
  "id": "CVE-2026-90186",
  "lastModified": "2026-09-17T17:17:13.127",
  "metrics": {},
  "published": "2026-09-17T17:17:13.127",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/1cdfe2fa62b48728a9b436fbbd3dbe4c11593e24"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/3e35ad503386a2e8a0e0460530dcbf421c79f6f2"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9c7bae099ddc92676ad1b7e29dd6c089e5f6196c"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/baff300541a0012907cdde349728739fe16176d7"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/f609f7bf9ce8c2fc427705c4a9f623a281239d06"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/fcd53f3e8b758c79c3f2420d28a2a1dce6fda61a"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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