flex_proportions: make fprop_new_period() hardirq safe (Linux Linux)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.13 % · percentile 3 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- Linux
- NVD status
- Analyzed
Description
In the Linux kernel, the following vulnerability has been resolved: flex_proportions: make fprop_new_period() hardirq safe Bernd has reported a lockdep splat from flexible proportions code that is essentially complaining about the following race: <timer fires> run_timer_softirq - we are in softirq context call_timer_fn writeout_period fprop_new_period write_seqcount_begin(&p->sequence); <hardirq is raised> ... blk_mq_end_request() blk_update_request() ext4_end_bio() folio_end_writeback() __wb_writeout_add() __fprop_add_percpu_max() if (unlikely(max_frac < FPROP_FRAC_BASE)) { fprop_fraction_percpu() seq = read_seqcount_begin(&p->sequence); - sees odd sequence so loops indefinitely Note that a deadlock like this is only possible if the bdi has configured maximum fraction of writeout throughput which is very rare in general but frequent for example for FUSE bdis. To fix this problem we have to make sure write section of the sequence counter is irqsafe.
References
- https://git.kernel.org/stable/c/0acc9ba7a1b5ba4d998c5753e709be904e179b75
- https://git.kernel.org/stable/c/884b2590ffcc7222cbbd6298051f4c243cc36f5d
- https://git.kernel.org/stable/c/78ede9ebd679dadf480dce6f7b798e3603f88348
- https://git.kernel.org/stable/c/b91a84299d72ae0e05551e851e47cd3008bd025b
- https://git.kernel.org/stable/c/dd9e2f5b38f1fdd49b1ab6d3a85f81c14369eacc
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H | NVD · nvd@nist.gov (Primary) |
European references
- ENISA EUVD · EUVD-2026-5870
- GCVE · GCVE-0-2026-23168
CERT-FR advisories
- CERTFR-2026-AVI-1093 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0954 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0928 — Multiples vulnérabilités dans le noyau Linux de Red Hat · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0926 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0831 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0787 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0746 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0697 — Multiples vulnérabilités dans le noyau Linux de SUSE · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0663 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0638 — Multiples vulnérabilités dans le noyau Linux d'Ubuntu · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.0 < 6.1.162cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.2 < 6.6.123cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.7 < 6.12.69cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*≥ 6.13 < 6.18.9cpe:2.3:o:linux:linux_kernel:6.19:rc1:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc2:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc3:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc4:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc5:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc6:*:*:*:*:*:*cpe:2.3:o:linux:linux_kernel:6.19:rc7:*:*:*:*:*:*
Affected products
| Product | Versions |
|---|---|
| Linux · Linux | affected a91befde350375b1ff954635acdde14dc92cd9a8 < 0acc9ba7a1b5ba4d998c5753e709be904e179b75 ; affected a91befde350375b1ff954635acdde14dc92cd9a8 < 884b2590ffcc7222cbbd6298051f4c243cc36f5d ; affected a91befde350375b1ff954635acdde14dc92cd9a8 < 78ede9ebd679dadf480dce6f7b798e3603f88348 ; affected a91befde350375b1ff954635acdde14dc92cd9a8 < b91a84299d72ae0e05551e851e47cd3008bd025b ; affected a91befde350375b1ff954635acdde14dc92cd9a8 < dd9e2f5b38f1fdd49b1ab6d3a85f81c14369eacc |
| Linux · Linux | affected 6.0 ; unaffected 0 < 6.0 ; unaffected 6.1.162 ≤ 6.1.* ; unaffected 6.6.123 ≤ 6.6.* ; unaffected 6.12.69 ≤ 6.12.* ; unaffected 6.18.9 ≤ 6.18.* |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |