{
   "containers": {
      "cna": {
         "providerMetadata": {
            "orgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038"
         },
         "descriptions": [
            {
               "lang": "en",
               "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ncgroup: Fix memory leak caused by missing cgroup_bpf_offline\n\nWhen enabling CONFIG_CGROUP_BPF, kmemleak can be observed by running\nthe command as below:\n\n    $mount -t cgroup -o none,name=foo cgroup cgroup/\n    $umount cgroup/\n\nunreferenced object 0xc3585c40 (size 64):\n  comm \"mount\", pid 425, jiffies 4294959825 (age 31.990s)\n  hex dump (first 32 bytes):\n    01 00 00 80 84 8c 28 c0 00 00 00 00 00 00 00 00  ......(.........\n    00 00 00 00 00 00 00 00 6c 43 a0 c3 00 00 00 00  ........lC......\n  backtrace:\n    [<e95a2f9e>] cgroup_bpf_inherit+0x44/0x24c\n    [<1f03679c>] cgroup_setup_root+0x174/0x37c\n    [<ed4b0ac5>] cgroup1_get_tree+0x2c0/0x4a0\n    [<f85b12fd>] vfs_get_tree+0x24/0x108\n    [<f55aec5c>] path_mount+0x384/0x988\n    [<e2d5e9cd>] do_mount+0x64/0x9c\n    [<208c9cfe>] sys_mount+0xfc/0x1f4\n    [<06dd06e0>] ret_fast_syscall+0x0/0x48\n    [<a8308cb3>] 0xbeb4daa8\n\nThis is because that since the commit 2b0d3d3e4fcf (\"percpu_ref: reduce\nmemory footprint of percpu_ref in fast path\") root_cgrp->bpf.refcnt.data\nis allocated by the function percpu_ref_init in cgroup_bpf_inherit which\nis called by cgroup_setup_root when mounting, but not freed along with\nroot_cgrp when umounting. Adding cgroup_bpf_offline which calls\npercpu_ref_kill to cgroup_kill_sb can free root_cgrp->bpf.refcnt.data in\numount path.\n\nThis patch also fixes the commit 4bfc0bb2c60e (\"bpf: decouple the lifetime\nof cgroup_bpf from cgroup itself\"). A cgroup_bpf_offline is needed to do a\ncleanup that frees the resources which are allocated by cgroup_bpf_inherit\nin cgroup_setup_root.\n\nAnd inside cgroup_bpf_offline, cgroup_get() is at the beginning and\ncgroup_put is at the end of cgroup_bpf_release which is called by\ncgroup_bpf_offline. So cgroup_bpf_offline can keep the balance of\ncgroup's refcount."
            }
         ],
         "affected": [
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "unaffected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/cgroup/cgroup.c"
               ],
               "versions": [
                  {
                     "version": "4bfc0bb2c60e",
                     "lessThan": "01599bf7cc2b",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "4bfc0bb2c60e",
                     "lessThan": "b529f88d9388",
                     "status": "affected",
                     "versionType": "git"
                  },
                  {
                     "version": "4bfc0bb2c60e",
                     "lessThan": "04f8ef5643bc",
                     "status": "affected",
                     "versionType": "git"
                  }
               ]
            },
            {
               "product": "Linux",
               "vendor": "Linux",
               "defaultStatus": "affected",
               "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
               "programFiles": [
                  "kernel/cgroup/cgroup.c"
               ],
               "versions": [
                  {
                     "version": "5.3",
                     "status": "affected"
                  },
                  {
                     "version": "0",
                     "lessThan": "5.3",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.10.77",
                     "lessThanOrEqual": "5.10.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.14.16",
                     "lessThanOrEqual": "5.14.*",
                     "status": "unaffected",
                     "versionType": "custom"
                  },
                  {
                     "version": "5.15",
                     "lessThanOrEqual": "*",
                     "status": "unaffected",
                     "versionType": "original_commit_for_fix"
                  }
               ]
            }
         ],
         "references": [
            {
               "url": "https://git.kernel.org/stable/c/01599bf7cc2b49c3d2be886cb438647dc25446ed"
            },
            {
               "url": "https://git.kernel.org/stable/c/b529f88d93884cf8ccafda793ee3d27b82fa578d"
            },
            {
               "url": "https://git.kernel.org/stable/c/04f8ef5643bcd8bcde25dfdebef998aea480b2ba"
            }
         ],
         "title": "cgroup: Fix memory leak caused by missing cgroup_bpf_offline",
         "x_generator": {
            "engine": "bippy-a5840b7849dd"
         }
      }
   },
   "cveMetadata": {
      "assignerOrgId": "f4215fc3-5b6b-47ff-a258-f7189bd81038",
      "cveID": "CVE-2021-47488",
      "requesterUserId": "gregkh@kernel.org",
      "serial": "1",
      "state": "PUBLISHED"
   },
   "dataType": "CVE_RECORD",
   "dataVersion": "5.0"
}