{
  "threat_severity" : "Moderate",
  "public_date" : "2024-05-22T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: mm, thp: bail out early in collapse_file for writeback page",
    "id" : "2282924",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2282924"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-372",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nmm, thp: bail out early in collapse_file for writeback page\nCurrently collapse_file does not explicitly check PG_writeback, instead,\npage_has_private and try_to_release_page are used to filter writeback\npages.  This does not work for xfs with blocksize equal to or larger\nthan pagesize, because in such case xfs has no page->private.\nThis makes collapse_file bail out early for writeback page.  Otherwise,\nxfs end_page_writeback will panic as follows.\npage:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32\naops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:\"libtest.so\"\nflags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback)\nraw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8\nraw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000\npage dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u))\npage->mem_cgroup:ffff0000c3e9a000\n------------[ cut here ]------------\nkernel BUG at include/linux/mm.h:1212!\nInternal error: Oops - BUG: 0 [#1] SMP\nModules linked in:\nBUG: Bad page state in process khugepaged  pfn:84ef32\nxfs(E)\npage:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32\nlibcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ...\nCPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ...\npstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--)\nCall trace:\nend_page_writeback+0x1c0/0x214\niomap_finish_page_writeback+0x13c/0x204\niomap_finish_ioend+0xe8/0x19c\niomap_writepage_end_bio+0x38/0x50\nbio_endio+0x168/0x1ec\nblk_update_request+0x278/0x3f0\nblk_mq_end_request+0x34/0x15c\nvirtblk_request_done+0x38/0x74 [virtio_blk]\nblk_done_softirq+0xc4/0x110\n__do_softirq+0x128/0x38c\n__irq_exit_rcu+0x118/0x150\nirq_exit+0x1c/0x30\n__handle_domain_irq+0x8c/0xf0\ngic_handle_irq+0x84/0x108\nel1_irq+0xcc/0x180\narch_cpu_idle+0x18/0x40\ndefault_idle_call+0x4c/0x1a0\ncpuidle_idle_call+0x168/0x1e0\ndo_idle+0xb4/0x104\ncpu_startup_entry+0x30/0x9c\nsecondary_start_kernel+0x104/0x180\nCode: d4210000 b0006161 910c8021 94013f4d (d4210000)\n---[ end trace 4a88c6a074082f8c ]---\nKernel panic - not syncing: Oops - BUG: Fatal exception in interrupt" ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support",
    "release_date" : "2024-09-18T00:00:00Z",
    "advisory" : "RHSA-2024:6753",
    "cpe" : "cpe:/o:redhat:rhel_aus:8.6",
    "package" : "kernel-0:4.18.0-372.123.1.el8_6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.6 Telecommunications Update Service",
    "release_date" : "2024-09-18T00:00:00Z",
    "advisory" : "RHSA-2024:6753",
    "cpe" : "cpe:/o:redhat:rhel_tus:8.6",
    "package" : "kernel-0:4.18.0-372.123.1.el8_6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions",
    "release_date" : "2024-09-18T00:00:00Z",
    "advisory" : "RHSA-2024:6753",
    "cpe" : "cpe:/o:redhat:rhel_e4s:8.6",
    "package" : "kernel-0:4.18.0-372.123.1.el8_6"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2021-47492\nhttps://nvd.nist.gov/vuln/detail/CVE-2021-47492\nhttps://lore.kernel.org/linux-cve-announce/2024052241-CVE-2021-47492-ee88@gregkh/T" ],
  "name" : "CVE-2021-47492",
  "csaw" : false
}