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Fencer Vulns
high 7.8

CVE-2021-47412 json

block: don't call rq_qos_ops->done_bio if the bio isn't tracked

published 2024-05-21 2 y ago modified 2026-08-05 3 mo ago also EUVD-2021-34417

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 14%
public exploits
0
none known

Summary

In the Linux kernel, the following vulnerability has been resolved:

block: don't call rq_qos_ops->done_bio if the bio isn't tracked

rq_qos framework is only applied on request based driver, so:

1) rq_qos_done_bio() needn't to be called for bio based driver

2) rq_qos_done_bio() needn't to be called for bio which isn't tracked, such as bios ended from error handling code.

Especially in bio_endio():

1) request queue is referred via bio->bi_bdev->bd_disk->queue, which may be gone since request queue refcount may not be held in above two cases

2) q->rq_qos may be freed in blk_cleanup_queue() when calling into __rq_qos_done_bio()

Fix the potential kernel panic by not calling rq_qos_ops->done_bio if the bio isn't tracked. This way is safe because both ioc_rqos_done_bio() and blkcg_iolatency_done_bio() are nop if the bio isn't tracked.

Patch / fix

  • Linux Linux 5.10.241, 5.14.11, 5.15
  • linux Debian 14, Debian 13, Debian 12 5.14.12-1

debian advisories DEBIAN-CVE-2021-47412

  • kernel RHEL 8 4.18.0-553.22.1.el8_10
  • perf RHEL 8 4.18.0-553.22.1.el8_10
  • bpftool RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-core RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-tools RHEL 8 4.18.0-553.22.1.el8_10
  • python3-perf RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-modules RHEL 8 4.18.0-553.22.1.el8_10
  • kernel-zfcpdump RHEL 8 4.18.0-553.22.1.el8_10

red hat advisories RHSA-2024:7000RHSA-2024:7001

  • dtb-aarch64 openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-64kb SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-syms SLE Module for Development Tools 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-obs-qa openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-source SLE Module for Development Tools 15 SP5, SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-default SLE Workstation Extension 15 SP5, SLE Module for Legacy 15 SP5, SLE Module for Basesystem 15 SP5 +4 more 5.14.21-150500.55.68.1
  • kernel-kvmsmall openSUSE Leap 15.5 5.14.21-150500.55.68.1
  • kernel-zfcpdump SLE Module for Basesystem 15 SP5, openSUSE Leap 15.5 5.14.21-150500.55.68.1

suse advisories SUSE-SU-2024:2190-1SUSE-SU-2024:2189-1SUSE-SU-2024:2019-1SUSE-SU-2024:2011-1SUSE-SU-2024:2008-1

  • kernel AlmaLinux 8 4.18.0-553.22.1.el8_10
  • perf AlmaLinux 8 4.18.0-553.22.1.el8_10
  • bpftool AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-core AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-tools AlmaLinux 8 4.18.0-553.22.1.el8_10
  • python3-perf AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-modules AlmaLinux 8 4.18.0-553.22.1.el8_10
  • kernel-zfcpdump AlmaLinux 8 4.18.0-553.22.1.el8_10

almalinux advisories ALSA-2024:7000ALSA-2024:7001

  • kernel Rocky Linux 8 4.18.0-553.22.1.el8_10
  • kernel-rt Rocky Linux 8 4.18.0-553.22.1.rt7.363.el8_10

rocky linux advisories RLSA-2024:7000RLSA-2024:7001

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-47412 updated cvss 4.7

kernel: block: don't call rq_qos_ops->done_bio if the bio isn't tracked

  • Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-553.22.1.el8_10, kernel 4.18.0-553.22.1.el8_10, bpftool 4.18.0-553.22.1.el8_10, kernel-core 4.18.0-553.22.1.el8_10, kernel-tools 4.18.0-553.22.1.el8_10, python3-perf 4.18.0-553.22.1.el8_10, +15 more Red Hat Enterprise Linux CRB (v. 8) kernel-debuginfo-common-x86_64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-aarch64 4.18.0-553.22.1.el8_10, kernel-debuginfo-common-ppc64le 4.18.0-553.22.1.el8_10
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.” RHSA-2024:7000
  • Red Hat Enterprise Linux NFV (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-kvm 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, +4 more Red Hat Enterprise Linux RT (v. 8) kernel-rt 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-core 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-debug-modules 4.18.0-553.22.1.rt7.363.el8_10, kernel-rt-modules-extra 4.18.0-553.22.1.rt7.363.el8_10, +2 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.” RHSA-2024:7001
  • Red Hat OpenShift AI 8 rhoai/odh-rhel8-operator v2.13.1-2, rhoai/odh-dashboard-rhel8 v2.13.1-1, rhoai/odh-modelmesh-rhel8 v2.13.1-1, rhoai/odh-operator-bundle v2.13.1-2, rhoai/odh-rhel8-operator v2.14.0-24, rhoai/odh-dashboard-rhel8 v2.14.0-11, +56 more
    fixed: vendor fix “Red Hat has investigated whether a possible mitigation exists for this issue, and has not been able to identify a practical example. Please update the affected package as soon as possible.” RHBA-2024:8413
  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
2 y ago

Exploit prediction

0.23% chance of exploitation in the next 30 days, higher than 14% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.