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TI-2021-22143 Aliases CVE-2021-47492GHSA-qm36-7xcx-862v

mm, thp: bail out early in collapse_file for writeback page

Priority LOW 33Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
High · High · High
Fix status
Partial Red Hat: 3 fixed, 3 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.

Summary

In the Linux kernel, the following vulnerability has been resolved: mm, thp: bail out early in collapse_file for writeback page Currently collapse_file does not explicitly check PG_writeback, instead, page_has_private and try_to_release_page are used to filter writeback pages. This does not work for xfs with blocksize equal to or larger than pagesize, because in such case xfs has no page->private. This makes collapse_file bail out early for writeback page. Otherwise, xfs end_page_writeback will panic as follows. page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:ffff0003f88c86a8 index:0x0 pfn:0x84ef32 aops:xfs_address_space_operations [xfs] ino:30000b7 dentry name:"libtest.so" flags: 0x57fffe0000008027(locked|referenced|uptodate|active|writeback) raw: 57fffe0000008027 ffff80001b48bc28 ffff80001b48bc28 ffff0003f88c86a8 raw: 0000000000000000 0000000000000000 00000000ffffffff ffff0000c3e9a000 page dumped because: VM_BUG_ON_PAGE(((unsigned int) page_ref_count(page) + 127u <= 127u)) page->mem_cgroup:ffff0000c3e9a000 ------------[ cut here ]------------ kernel BUG at include/linux/mm.h:1212! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: BUG: Bad page state in process khugepaged pfn:84ef32 xfs(E) page:fffffe00201bcc80 refcount:0 mapcount:0 mapping:0 index:0x0 pfn:0x84ef32 libcrc32c(E) rfkill(E) aes_ce_blk(E) crypto_simd(E) ... CPU: 25 PID: 0 Comm: swapper/25 Kdump: loaded Tainted: ... pstate: 60400005 (nZCv daif +PAN -UAO -TCO BTYPE=--) Call trace: end_page_writeback+0x1c0/0x214 iomap_finish_page_writeback+0x13c/0x204 iomap_finish_ioend+0xe8/0x19c iomap_writepage_end_bio+0x38/0x50 bio_endio+0x168/0x1ec blk_update_request+0x278/0x3f0 blk_mq_end_request+0x34/0x15c virtblk_request_done+0x38/0x74 [virtio_blk] blk_done_softirq+0xc4/0x110 __do_softirq+0x128/0x38c __irq_exit_rcu+0x118/0x150 irq_exit+0x1c/0x30 __handle_domain_irq+0x8c/0xf0 gic_handle_irq+0x84/0x108 el1_irq+0xcc/0x180 arch_cpu_idle+0x18/0x40 default_idle_call+0x4c/0x1a0 cpuidle_idle_call+0x168/0x1e0 do_idle+0xb4/0x104 cpu_startup_entry+0x30/0x9c secondary_start_kernel+0x104/0x180 Code: d4210000 b0006161 910c8021 94013f4d (d4210000) ---[ end trace 4a88c6a074082f8c ]--- Kernel panic - not syncing: Oops - BUG: Fatal exception in interrupt

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00218 12th percentileScored 2026-11-07
Fix Partial Linux (Linux): 5.10.77, 5.14.16, 5.15Red Hat: 1 advisoryRed Hat: 3 fixed, 3 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
LinuxLinux5.4 and later5.10.77, 5.14.16, 5.15Patch availableCNA
  • Linux VendorLinux Affected 5.4 and later Fixed in 5.10.77, 5.14.16, 5.15 Patch available CNA

CPE configurations NVD · 8

CPEVersionsRoleVendor
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*5.4 to before 5.10.77; 5.11 to before 5.14.16VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*5.15 rc1VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*5.15 rc2VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*5.15 rc3VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*5.15 rc4VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*5.15 rc5VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:*5.15 rc6VulnerableLinux
cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:*5.15 rc7VulnerableLinux
  • cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.4 to before 5.10.77; 5.11 to before 5.14.16 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:* Versions 5.15 rc1 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:* Versions 5.15 rc2 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:* Versions 5.15 rc3 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:* Versions 5.15 rc4 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:* Versions 5.15 rc5 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:* Versions 5.15 rc6 Vulnerable ·Linux
  • cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:* Versions 5.15 rc7 Vulnerable ·Linux

Remediation

  • Fix · CNA Linux (Linux) Fixed in 5.10.77, 5.14.16, 5.15

Red Hat 1 advisory

  • RHSA-2024:6753 Released 2024-09-18 · Red Hat rating Moderate
    kernel security update
    • Red Hat Enterprise Linux BaseOS AUS (v.8.6) bpftool-4.18.0-372.123.1.el8_6, kernel-4.18.0-372.123.1.el8_6, kernel-abi-stablelists-4.18.0-372.123.1.el8_6 +14
    • Red Hat Enterprise Linux BaseOS E4S (v.8.6) bpftool-4.18.0-372.123.1.el8_6, kernel-4.18.0-372.123.1.el8_6, kernel-abi-stablelists-4.18.0-372.123.1.el8_6 +19
    • Red Hat Enterprise Linux BaseOS TUS (v.8.6) bpftool-4.18.0-372.123.1.el8_6, kernel-4.18.0-372.123.1.el8_6, kernel-abi-stablelists-4.18.0-372.123.1.el8_6 +14

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 6AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 7AffectedNo fix planned: Out of support scope
Red Hat Enterprise Linux 8AffectedNo fix yet
Red Hat Enterprise Linux BaseOS AUS (v.8.6)Fixed RHSA-2024:6753
Red Hat Enterprise Linux BaseOS E4S (v.8.6)Fixed RHSA-2024:6753
Red Hat Enterprise Linux BaseOS TUS (v.8.6)Fixed RHSA-2024:6753
Not affected: 1 product
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2021-47492
  2. 2026-10-03 Alias added: GHSA-qm36-7xcx-862v

References

Patch 3

  • TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
  • TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
  • TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
  • TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
  • TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
See all 15278 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences