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FKIE_CVE-2026-74348

Vulnerability from fkie_nvd - Published: 2026-08-15 06:22 - Updated: 2026-08-17 06:19
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved: ocfs2/dlm: require a ref for locking_state debugfs open debug_lockres_open() copies inode->i_private into struct debug_lockres and debug_lockres_release() later drops that pointer with dlm_put(). That only works if open successfully pins the struct dlm_ctxt. Today open calls dlm_grab(dlm) but ignores its return value. Once the last domain unregister has removed the context from dlm_domains, dlm_grab() returns NULL, yet open still stores the raw pointer and returns success. The later release path is outside the debugfs removal barrier, so it can call dlm_put() after dlm_free_ctxt_mem() has freed the context. KASAN reports this as a slab-use-after-free in dlm_put() called from debug_lockres_release(). Fail the open when dlm_grab() cannot acquire the reference and unwind the seq_file private state before returning. That keeps locking_state from handing out a file descriptor whose release path does not own the dlm_ctxt. The buggy scenario involves two paths, with each column showing the order within that path: locking_state debugfs open: last domain unregister: 1. debug_lockres_open() reads 1. dlm_unregister_domain() calls inode->i_private. dlm_complete_dlm_shutdown(). 2. debug_lockres_open() calls 2. shutdown removes the dlm_ctxt from dlm_grab(dlm) and gets NULL. dlm_domains. 3. open still stores the raw dlm 3. final teardown reaches pointer in dl->dl_ctxt and dlm_free_ctxt_mem() and frees it. returns success. 4. debug_lockres_release() later calls dlm_put(dl->dl_ctxt). Validation reproduced this kernel report: KASAN slab-use-after-free in dlm_put+0x82/0x200 RIP: 0033:0x7f4d349bc9e0 The buggy address belongs to the object at ffff888103a3c000 which belongs to the cache kmalloc-2k of size 2048 The buggy address is located 816 bytes inside of freed 2048-byte region [ffff888103a3c000, ffff888103a3c800) Write of size 4 Call trace: dump_stack_lvl+0x66/0xa0 (?:?) print_report+0xd0/0x630 (?:?) dlm_put+0x82/0x200 (?:?) srso_alias_return_thunk+0x5/0xfbef5 (?:?) __virt_addr_valid+0x188/0x2f0 (?:?) kasan_report+0xe4/0x120 (?:?) kasan_check_range+0x105/0x1b0 (?:?) debug_lockres_release+0x53/0x80 (fs/ocfs2/dlm/dlmdebug.c:587) dlm_put+0x9/0x200 (?:?) debug_lockres_release+0x5c/0x80 (fs/ocfs2/dlm/dlmdebug.c:587) full_proxy_release+0x67/0x90 (?:?) __fput+0x1df/0x4b0 (?:?) do_raw_spin_lock+0x10f/0x1b0 (?:?) fput_close_sync+0xd2/0x170 (?:?) __x64_sys_close+0x55/0x90 (?:?) do_syscall_64+0x10c/0x640 (arch/x86/entry/syscall_64.c:87) irqentry_exit+0xac/0x6e0 (?:?) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) Freed by task stack: kasan_save_stack+0x33/0x60 (?:?) kasan_save_track+0x14/0x30 (?:?) kasan_save_free_info+0x3b/0x60 (?:?) __kasan_slab_free+0x5f/0x80 (?:?) kfree+0x30f/0x580 (?:?) dlm_put+0x1ce/0x200 (?:?) dlm_unregister_domain+0xf6/0xb30 (?:?) o2cb_cluster_disconnect+0x6b/0x90 (?:?) ocfs2_cluster_disconnect+0x41/0x70 (?:?) ocfs2_dlm_shutdown+0x1c4/0x220 (?:?) ocfs2_dismount_volume+0x38a/0x550 (?:?) generic_shutdown_super+0xc3/0x220 (?:?) kill_block_super+0x29/0x60 (?:?) deactivate_locked_super+0x66/0xe0 (?:?) cleanup_mnt+0x13d/0x210 (?:?) task_work_run+0xfa/0x170 (?:?) exit_to_user_mode_loop+0xd6/0x430 (?:?) do_syscall_64+0x3cb/0x640 (arch/x86/entry/syscall_64.c:87) entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/03ad858ce8064861ea580021976dc19b7aabb549
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/5bee5d5f67aedd26d2b72e00e49dd93331fbcc30
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/6cc93dea4078cbcddee63fa2234e382a76600464
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/90a6512425414098a63fc97b77bed089c75d106b
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a087b2d3411e7f9df71ba3293596923ee2c70d65
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/a09831214912a1f270663d935613910fafd8d883
416baaa9-dc9f-4396-8d5f-8c081fb06d67https://git.kernel.org/stable/c/aa7883b6a3c76301a3299deb34de948e73bb6a08
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/dlm/dlmdebug.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "6cc93dea4078cbcddee63fa2234e382a76600464",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "90a6512425414098a63fc97b77bed089c75d106b",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "5bee5d5f67aedd26d2b72e00e49dd93331fbcc30",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "aa7883b6a3c76301a3299deb34de948e73bb6a08",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "a087b2d3411e7f9df71ba3293596923ee2c70d65",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "a09831214912a1f270663d935613910fafd8d883",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            },
            {
              "lessThan": "03ad858ce8064861ea580021976dc19b7aabb549",
              "status": "affected",
              "version": "4e3d24ed1a1285fe3289653aacc965642706bacb",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "fs/ocfs2/dlm/dlmdebug.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.26"
            },
            {
              "lessThan": "2.6.26",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.261",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.212",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.178",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.145",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.97",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.1.*",
              "status": "unaffected",
              "version": "7.1.5",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.2",
              "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\nocfs2/dlm: require a ref for locking_state debugfs open\n\ndebug_lockres_open() copies inode-\u003ei_private into struct debug_lockres and\ndebug_lockres_release() later drops that pointer with dlm_put().  That\nonly works if open successfully pins the struct dlm_ctxt.\n\nToday open calls dlm_grab(dlm) but ignores its return value.  Once the\nlast domain unregister has removed the context from dlm_domains,\ndlm_grab() returns NULL, yet open still stores the raw pointer and returns\nsuccess.  The later release path is outside the debugfs removal barrier,\nso it can call dlm_put() after dlm_free_ctxt_mem() has freed the context. \nKASAN reports this as a slab-use-after-free in dlm_put() called from\ndebug_lockres_release().\n\nFail the open when dlm_grab() cannot acquire the reference and unwind the\nseq_file private state before returning.  That keeps locking_state from\nhanding out a file descriptor whose release path does not own the\ndlm_ctxt.\n\nThe buggy scenario involves two paths, with each column showing the order\nwithin that path:\n\nlocking_state debugfs open:          last domain unregister:\n1. debug_lockres_open() reads        1. dlm_unregister_domain() calls\n   inode-\u003ei_private.                    dlm_complete_dlm_shutdown().\n2. debug_lockres_open() calls        2. shutdown removes the dlm_ctxt from\n   dlm_grab(dlm) and gets NULL.         dlm_domains.\n3. open still stores the raw dlm     3. final teardown reaches\n   pointer in dl-\u003edl_ctxt and           dlm_free_ctxt_mem() and frees it.\n   returns success.\n4. debug_lockres_release() later\n   calls dlm_put(dl-\u003edl_ctxt).\n\nValidation reproduced this kernel report:\nKASAN slab-use-after-free in dlm_put+0x82/0x200\nRIP: 0033:0x7f4d349bc9e0\nThe buggy address belongs to the object at ffff888103a3c000 which belongs\nto the cache kmalloc-2k of size 2048\nThe buggy address is located 816 bytes inside of freed 2048-byte region\n[ffff888103a3c000, ffff888103a3c800)\nWrite of size 4\nCall trace:\n  dump_stack_lvl+0x66/0xa0 (?:?)\n  print_report+0xd0/0x630 (?:?)\n  dlm_put+0x82/0x200 (?:?)\n  srso_alias_return_thunk+0x5/0xfbef5 (?:?)\n  __virt_addr_valid+0x188/0x2f0 (?:?)\n  kasan_report+0xe4/0x120 (?:?)\n  kasan_check_range+0x105/0x1b0 (?:?)\n  debug_lockres_release+0x53/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)\n  dlm_put+0x9/0x200 (?:?)\n  debug_lockres_release+0x5c/0x80 (fs/ocfs2/dlm/dlmdebug.c:587)\n  full_proxy_release+0x67/0x90 (?:?)\n  __fput+0x1df/0x4b0 (?:?)\n  do_raw_spin_lock+0x10f/0x1b0 (?:?)\n  fput_close_sync+0xd2/0x170 (?:?)\n  __x64_sys_close+0x55/0x90 (?:?)\n  do_syscall_64+0x10c/0x640 (arch/x86/entry/syscall_64.c:87)\n  irqentry_exit+0xac/0x6e0 (?:?)\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)\nFreed by task stack:\n  kasan_save_stack+0x33/0x60 (?:?)\n  kasan_save_track+0x14/0x30 (?:?)\n  kasan_save_free_info+0x3b/0x60 (?:?)\n  __kasan_slab_free+0x5f/0x80 (?:?)\n  kfree+0x30f/0x580 (?:?)\n  dlm_put+0x1ce/0x200 (?:?)\n  dlm_unregister_domain+0xf6/0xb30 (?:?)\n  o2cb_cluster_disconnect+0x6b/0x90 (?:?)\n  ocfs2_cluster_disconnect+0x41/0x70 (?:?)\n  ocfs2_dlm_shutdown+0x1c4/0x220 (?:?)\n  ocfs2_dismount_volume+0x38a/0x550 (?:?)\n  generic_shutdown_super+0xc3/0x220 (?:?)\n  kill_block_super+0x29/0x60 (?:?)\n  deactivate_locked_super+0x66/0xe0 (?:?)\n  cleanup_mnt+0x13d/0x210 (?:?)\n  task_work_run+0xfa/0x170 (?:?)\n  exit_to_user_mode_loop+0xd6/0x430 (?:?)\n  do_syscall_64+0x3cb/0x640 (arch/x86/entry/syscall_64.c:87)\n  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)"
    }
  ],
  "id": "CVE-2026-74348",
  "lastModified": "2026-08-17T06:19:29.400",
  "metrics": {},
  "published": "2026-08-15T06:22:35.970",
  "references": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/03ad858ce8064861ea580021976dc19b7aabb549"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/5bee5d5f67aedd26d2b72e00e49dd93331fbcc30"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/6cc93dea4078cbcddee63fa2234e382a76600464"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/90a6512425414098a63fc97b77bed089c75d106b"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/9c81c1a61a52b6ecf0d14f1dbd95f154a7a9e92a"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a087b2d3411e7f9df71ba3293596923ee2c70d65"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/a09831214912a1f270663d935613910fafd8d883"
    },
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "url": "https://git.kernel.org/stable/c/aa7883b6a3c76301a3299deb34de948e73bb6a08"
    }
  ],
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Received"
}



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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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