# CVE-2021-47493: linux: In the Linux kernel, the following vulnerability has been resolved:  ocfs2: fix race between searching chunks and rel...

CVE-2021-47493 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47493, released May 22, 2024. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2021-47493
- Priority: Routine
- CVSS: 4.7 (medium)
- EPSS: 0.0017
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: May 22, 2024

## Description

In the Linux kernel, the following vulnerability has been resolved:  ocfs2: fix race between searching chunks and release journal_head from buffer_head  Encountered a race between ocfs2_test_bg_bit_allocatable() and jbd2_journal_put_journal_head() resulting in the below vmcore.    PID: 106879  TASK: ffff880244ba9c00  CPU: 2   COMMAND: "loop3"   Call trace:     panic     oops_end     no_context     __bad_area_nosemaphore     bad_area_nosemaphore     __do_page_fault     do_page_fault     page_fault       [exception RIP: ocfs2_block_group_find_clear_bits+316]     ocfs2_block_group_find_clear_bits [ocfs2]     ocfs2_cluster_group_search [ocfs2]     ocfs2_search_chain [ocfs2]     ocfs2_claim_suballoc_bits [ocfs2]     __ocfs2_claim_clusters [ocfs2]     ocfs2_claim_clusters [ocfs2]     ocfs2_local_alloc_slide_window [ocfs2]     ocfs2_reserve_local_alloc_bits [ocfs2]     ocfs2_reserve_clusters_with_limit [ocfs2]     ocfs2_reserve_clusters [ocfs2]     ocfs2_lock_refcount_allocators [ocfs2]     ocfs2_make_clusters_writable [ocfs2]     ocfs2_replace_cow [ocfs2]     ocfs2_refcount_cow [ocfs2]     ocfs2_file_write_iter [ocfs2]     lo_rw_aio     loop_queue_work     kthread_worker_fn     kthread     ret_from_fork  When ocfs2_test_bg_bit_allocatable() called bh2jh(bg_bh), the bg_bh->b_private NULL as jbd2_journal_put_journal_head() raced and released the jounal head from the buffer head.  Needed to take bit lock for the bit 'BH_JournalHead' to fix this race.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 12.15 (bookworm) | 5.15.3-1 | [DEBIAN-CVE-2021-47493](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47493.md) | May 22, 2024 |
| Linux | linux Debian 13.5 (trixie) | 5.15.3-1 | [DEBIAN-CVE-2021-47493](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47493.md) | May 22, 2024 |
| Linux | linux Debian 14 | 5.15.3-1 | [DEBIAN-CVE-2021-47493](https://patchblox.com/security/data/fix/linux/debian-cve-2021-47493.md) | May 22, 2024 |

---

Data as of 2026-11-09T13:31:49Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.