CVE-2026-46079 (GCVE-0-2026-46079)
Vulnerability from cvelistv5
Published
2026-05-27 12:58
Modified
2026-06-14 17:52
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: rbd: fix null-ptr-deref when device_add_disk() fails do_rbd_add() publishes the device with device_add() before calling device_add_disk(). If device_add_disk() fails after device_add() succeeds, the error path calls rbd_free_disk() directly and then later falls through to rbd_dev_device_release(), which calls rbd_free_disk() again. This double teardown can leave blk-mq cleanup operating on invalid state and trigger a null-ptr-deref in __blk_mq_free_map_and_rqs(), reached from blk_mq_free_tag_set(). Fix this by following the normal remove ordering: call device_del() before rbd_dev_device_release() when device_add_disk() fails after device_add(). That keeps the teardown sequence consistent and avoids re-entering disk cleanup through the wrong path. The bug was first flagged by an experimental analysis tool we are developing for kernel memory-management bugs while analyzing v6.13-rc1. The tool is still under development and is not yet publicly available. We reproduced the bug on v7.0 with a real Ceph backend and a QEMU x86_64 guest booted with KASAN and CONFIG_FAILSLAB enabled. The reproducer confines failslab injections to the __add_disk() range and injects fail-nth while mapping an RBD image through /sys/bus/rbd/add_single_major. On the unpatched kernel, fail-nth=4 reliably triggered the fault: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 UID: 0 PID: 273 Comm: bash Not tainted 7.0.0-01247-gd60bc1401583 #6 PREEMPT(lazy) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:__blk_mq_free_map_and_rqs+0x8c/0x240 Code: 00 00 48 8b 6b 60 41 89 f4 49 c1 e4 03 4c 01 e5 45 85 ed 0f 85 0a 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 e9 48 c1 e9 03 <80> 3c 01 00 0f 85 31 01 00 00 4c 8b 6d 00 4d 85 ed 0f 84 e2 00 00 RSP: 0018:ff1100000ab0fac8 EFLAGS: 00000246 RAX: dffffc0000000000 RBX: ff1100000c4806a0 RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000000000 RDI: ff1100000c4806f4 RBP: 0000000000000000 R08: 0000000000000001 R09: ffe21c000189001b R10: ff1100000c4800df R11: ff1100006cf37be0 R12: 0000000000000000 R13: 0000000000000000 R14: ff1100000c480700 R15: ff1100000c480004 FS: 00007f0fbe8fe740(0000) GS:ff110000e5851000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fe53473b2e0 CR3: 0000000012eef000 CR4: 00000000007516f0 PKRU: 55555554 Call Trace: <TASK> blk_mq_free_tag_set+0x77/0x460 do_rbd_add+0x1446/0x2b80 ? __pfx_do_rbd_add+0x10/0x10 ? lock_acquire+0x18c/0x300 ? find_held_lock+0x2b/0x80 ? sysfs_file_kobj+0xb6/0x1b0 ? __pfx_sysfs_kf_write+0x10/0x10 kernfs_fop_write_iter+0x2f4/0x4a0 vfs_write+0x98e/0x1000 ? expand_files+0x51f/0x850 ? __pfx_vfs_write+0x10/0x10 ksys_write+0xf2/0x1d0 ? __pfx_ksys_write+0x10/0x10 do_syscall_64+0x115/0x690 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f0fbea15907 Code: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24 RSP: 002b:00007ffe22346ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f0fbea15907 RDX: 0000000000000058 RSI: 0000563ace6c0ef0 RDI: 0000000000000001 RBP: 0000563ace6c0ef0 R08: 0000563ace6c0ef0 R09: 6b6435726d694141 R10: 5250337279762f78 R11: 0000000000000246 R12: 0000000000000058 R13: 00007f0fbeb1c780 R14: ff1100000c480700 R15: ff1100000c480004 </TASK> With this fix applied, rerunning the reproducer over fail-nth=1..256 yields no KASAN reports. [ idryomov: rename err_out_device_del -> err_out_device ]
References
Impacted products
Vendor Product Version
Linux Linux Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
Version: 27c97abc30e2b9ad2288977c0ecbef4d50553f57
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{
  "containers": {
    "cna": {
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        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/block/rbd.c"
          ],
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          "vendor": "Linux",
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              "status": "unaffected",
              "version": "6.12.86",
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              "lessThanOrEqual": "6.18.*",
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              "version": "6.18.27",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
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                  "vulnerable": true
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              "negate": false,
              "operator": "OR"
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      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrbd: fix null-ptr-deref when device_add_disk() fails\n\ndo_rbd_add() publishes the device with device_add() before calling\ndevice_add_disk(). If device_add_disk() fails after device_add()\nsucceeds, the error path calls rbd_free_disk() directly and then later\nfalls through to rbd_dev_device_release(), which calls rbd_free_disk()\nagain. This double teardown can leave blk-mq cleanup operating on\ninvalid state and trigger a null-ptr-deref in\n__blk_mq_free_map_and_rqs(), reached from blk_mq_free_tag_set().\n\nFix this by following the normal remove ordering: call device_del()\nbefore rbd_dev_device_release() when device_add_disk() fails after\ndevice_add(). That keeps the teardown sequence consistent and avoids\nre-entering disk cleanup through the wrong path.\n\nThe bug was first flagged by an experimental analysis tool we are\ndeveloping for kernel memory-management bugs while analyzing\nv6.13-rc1. The tool is still under development and is not yet publicly\navailable.\n\nWe reproduced the bug on v7.0 with a real Ceph backend and a QEMU x86_64\nguest booted with KASAN and CONFIG_FAILSLAB enabled. The reproducer\nconfines failslab injections to the __add_disk() range and injects\nfail-nth while mapping an RBD image through\n/sys/bus/rbd/add_single_major.\n\nOn the unpatched kernel, fail-nth=4 reliably triggered the fault:\n\n\tOops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI\n\tKASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]\n\tCPU: 0 UID: 0 PID: 273 Comm: bash Not tainted 7.0.0-01247-gd60bc1401583 #6 PREEMPT(lazy)\n\tHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014\n\tRIP: 0010:__blk_mq_free_map_and_rqs+0x8c/0x240\n\tCode: 00 00 48 8b 6b 60 41 89 f4 49 c1 e4 03 4c 01 e5 45 85 ed 0f 85 0a 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 e9 48 c1 e9 03 \u003c80\u003e 3c 01 00 0f 85 31 01 00 00 4c 8b 6d 00 4d 85 ed 0f 84 e2 00 00\n\tRSP: 0018:ff1100000ab0fac8 EFLAGS: 00000246\n\tRAX: dffffc0000000000 RBX: ff1100000c4806a0 RCX: 0000000000000000\n\tRDX: 0000000000000002 RSI: 0000000000000000 RDI: ff1100000c4806f4\n\tRBP: 0000000000000000 R08: 0000000000000001 R09: ffe21c000189001b\n\tR10: ff1100000c4800df R11: ff1100006cf37be0 R12: 0000000000000000\n\tR13: 0000000000000000 R14: ff1100000c480700 R15: ff1100000c480004\n\tFS:  00007f0fbe8fe740(0000) GS:ff110000e5851000(0000) knlGS:0000000000000000\n\tCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n\tCR2: 00007fe53473b2e0 CR3: 0000000012eef000 CR4: 00000000007516f0\n\tPKRU: 55555554\n\tCall Trace:\n\t \u003cTASK\u003e\n\t blk_mq_free_tag_set+0x77/0x460\n\t do_rbd_add+0x1446/0x2b80\n\t ? __pfx_do_rbd_add+0x10/0x10\n\t ? lock_acquire+0x18c/0x300\n\t ? find_held_lock+0x2b/0x80\n\t ? sysfs_file_kobj+0xb6/0x1b0\n\t ? __pfx_sysfs_kf_write+0x10/0x10\n\t kernfs_fop_write_iter+0x2f4/0x4a0\n\t vfs_write+0x98e/0x1000\n\t ? expand_files+0x51f/0x850\n\t ? __pfx_vfs_write+0x10/0x10\n\t ksys_write+0xf2/0x1d0\n\t ? __pfx_ksys_write+0x10/0x10\n\t do_syscall_64+0x115/0x690\n\t entry_SYSCALL_64_after_hwframe+0x77/0x7f\n\tRIP: 0033:0x7f0fbea15907\n\tCode: 10 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 \u003c48\u003e 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24\n\tRSP: 002b:00007ffe22346ea8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001\n\tRAX: ffffffffffffffda RBX: 0000000000000058 RCX: 00007f0fbea15907\n\tRDX: 0000000000000058 RSI: 0000563ace6c0ef0 RDI: 0000000000000001\n\tRBP: 0000563ace6c0ef0 R08: 0000563ace6c0ef0 R09: 6b6435726d694141\n\tR10: 5250337279762f78 R11: 0000000000000246 R12: 0000000000000058\n\tR13: 00007f0fbeb1c780 R14: ff1100000c480700 R15: ff1100000c480004\n\t \u003c/TASK\u003e\n\nWith this fix applied, rerunning the reproducer over fail-nth=1..256\nyields no KASAN reports.\n\n[ idryomov: rename err_out_device_del -\u003e err_out_device ]"
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-06-14T17:52:46.214Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/78bd0c143dea4b7a4c23c13356987ca0eafb442e"
        },
        {
          "url": "https://git.kernel.org/stable/c/2f4809a879f0750c7790bbeeae86c9505797a06f"
        },
        {
          "url": "https://git.kernel.org/stable/c/564cd8f4aeb9a938e470c5c91922fd02e4d41acc"
        },
        {
          "url": "https://git.kernel.org/stable/c/ad0126ffcba8777109852979eaaa6dca6703abdb"
        },
        {
          "url": "https://git.kernel.org/stable/c/059fb7656723c1b77c2fc0e64b7aa99d6bb65e8e"
        },
        {
          "url": "https://git.kernel.org/stable/c/d1fef92e414433ca7b89abf85cb0df42b8d475eb"
        }
      ],
      "title": "rbd: fix null-ptr-deref when device_add_disk() fails",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46079",
    "datePublished": "2026-05-27T12:58:13.903Z",
    "dateReserved": "2026-05-13T15:03:33.096Z",
    "dateUpdated": "2026-06-14T17:52:46.214Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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