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CVE-2026-99173

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: eventfs: Free the eventfs_inode after an rcu grace period too tracefs_d_revalidate() reads ->is_freed of the eventfs_inode that dentry->d_fsdata points to, and ->d_revalidate() is called in rcu pathwalk mode with nothing but rcu_read_lock() held. The dentry itself stays around for such a walker, but tracefs_d_release() drops its reference to the eventfs_inode when the dentry is killed, and release_ei() then frees it after a grace period of eventfs_srcu. An SRCU grace period doesn't wait for rcu_read_lock() sections, so the walker can read an eventfs_inode that is already gone. With a pathwalk held up in tracefs_d_revalidate() while the dentry goes away: BUG: KASAN: slab-use-after-free in tracefs_d_revalidate+0x76/0x90 Read of size 1 at addr ff1100010152d8d0 by task walker/97 Call Trace: <TASK> tracefs_d_revalidate+0x76/0x90 lookup_fast+0x320/0x640 path_lookupat+0x160/0xb00 filename_lookup+0x1f1/0x5b0 vfs_statx+0xd7/0x3b0 vfs_fstatat+0x4d/0x90 __do_sys_newfstatat+0xa0/0x100 do_syscall_64+0x10e/0x5e0 entry_SYSCALL_64_after_hwframe+0x77/0x7f [...] Allocated by task 1: __kmalloc_cache_noprof+0x249/0x560 eventfs_create_dir+0x7a/0x590 event_create_dir+0x2fb/0xcf0 trace_add_event_call+0xbf/0x150 [...] Freed by task 11: kfree+0x1db/0x5b0 srcu_invoke_callbacks+0x3a3/0x620 process_one_work+0x937/0x1810 worker_thread+0x4f1/0xd60 Before commit 8e556432477e ("eventfs: Use SRCU for freeing eventfs_inodes") release_ei() used call_rcu(), which covered the walker, while eventfs_iterate() needs the SRCU grace period. Wait for both and chain call_rcu() from the SRCU callback.

Severity
Not scored
CVSS score
Not available
Vulnerability status
Received
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2026-10-28 11:17:37.900000
Last modified
2026-10-28 11:17:37.900000
View original CVE JSON
{
  "id": "CVE-2026-99173",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-10-28T11:17:37.900",
  "lastModified": "2026-10-28T11:17:37.900",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\neventfs: Free the eventfs_inode after an rcu grace period too\n\ntracefs_d_revalidate() reads ->is_freed of the eventfs_inode that\ndentry->d_fsdata points to, and ->d_revalidate() is called in rcu\npathwalk mode with nothing but rcu_read_lock() held. The dentry itself\nstays around for such a walker, but tracefs_d_release() drops its\nreference to the eventfs_inode when the dentry is killed, and\nrelease_ei() then frees it after a grace period of eventfs_srcu. An\nSRCU grace period doesn't wait for rcu_read_lock() sections, so the\nwalker can read an eventfs_inode that is already gone.\n\nWith a pathwalk held up in tracefs_d_revalidate() while the dentry goes\naway:\n\n  BUG: KASAN: slab-use-after-free in tracefs_d_revalidate+0x76/0x90\n  Read of size 1 at addr ff1100010152d8d0 by task walker/97\n  Call Trace:\n   <TASK>\n   tracefs_d_revalidate+0x76/0x90\n   lookup_fast+0x320/0x640\n   path_lookupat+0x160/0xb00\n   filename_lookup+0x1f1/0x5b0\n   vfs_statx+0xd7/0x3b0\n   vfs_fstatat+0x4d/0x90\n   __do_sys_newfstatat+0xa0/0x100\n   do_syscall_64+0x10e/0x5e0\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  [...]\n  Allocated by task 1:\n   __kmalloc_cache_noprof+0x249/0x560\n   eventfs_create_dir+0x7a/0x590\n   event_create_dir+0x2fb/0xcf0\n   trace_add_event_call+0xbf/0x150\n  [...]\n  Freed by task 11:\n   kfree+0x1db/0x5b0\n   srcu_invoke_callbacks+0x3a3/0x620\n   process_one_work+0x937/0x1810\n   worker_thread+0x4f1/0xd60\n\nBefore commit 8e556432477e (\"eventfs: Use SRCU for freeing\neventfs_inodes\") release_ei() used call_rcu(), which covered the walker,\nwhile eventfs_iterate() needs the SRCU grace period. Wait for both and\nchain call_rcu() from the SRCU callback."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "fs/tracefs/event_inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "8e556432477e97ad6179c61b61a32bf5f1af2355",
              "lessThan": "4586ef24ce390e8becb9f3e5852d5d3978b01c33",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "8e556432477e97ad6179c61b61a32bf5f1af2355",
              "lessThan": "45fcfd5d9c10e0aa977ed5b9bd445707e01bb107",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "8e556432477e97ad6179c61b61a32bf5f1af2355",
              "lessThan": "2cd88c498ecff8e22bf4c397b8eb226db70ac343",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "2ef3d120d19faba3dec35b10a025b00db0284373",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "384f383c5aa7bfd619d9f56a513a36e533428186",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "6.6.46",
              "lessThan": "6.7",
              "versionType": "semver",
              "status": "affected"
            },
            {
              "version": "6.10.5",
              "lessThan": "6.11",
              "versionType": "semver",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "fs/tracefs/event_inode.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.11",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.11",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.59",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.13",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/2cd88c498ecff8e22bf4c397b8eb226db70ac343",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4586ef24ce390e8becb9f3e5852d5d3978b01c33",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/45fcfd5d9c10e0aa977ed5b9bd445707e01bb107",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}