Reference page — cumulative record through Wednesday, August 19, 2026 UTC. Reference pages update as the archive grows; only dated daily editions are immutable pages of record.
Linux Linux — ocfs2: fix race between searching chunks and release journal_head from buffer_head
AV AC PR UI S C I A CVSS EPSS %ile KEV
L H L N U N N H 4.7 .0017 7.0 —
AFFECTED
Product Versions Fixed
Linux ccd979bdbce9fba8412beb3f1de68a9d0171b12c – —
Linux 2.6.16 – 5.10.77
TIMELINE
May 22 Reserved by Linux
May 22 Published (CNA: Linux)
Aug 4 RESCORED — CVE-2021-47493 (Linux). CVSS 7.8 → 4.7 (NVD).
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.
Lifecycle
Complete event history — 3 events, chronological
| Date | Event | Detail |
| May 22, 2024 | Reserved | Reserved by Linux |
| May 22, 2024 | Published | Published (CNA: Linux) |
| August 4, 2026 | RESCORED | RESCORED — CVE-2021-47493 (Linux). CVSS 7.8 → 4.7 (NVD). |
Affected
Affected products and packages — 2 rows
| Vendor | Product / Package | Ecosystem | Version introduced | Fixed |
| Linux | Linux | — | ccd979bdbce9fba8412beb3f1de68a9d0171b12c | — |
| Linux | Linux | — | 2.6.16 | 5.10.77 |
About this page
This is a reference page, not a dated page of record. It assembles the complete lifecycle of CVE-2021-47493 from the CVE Program record, NVD enrichment, the CISA KEV catalog, EPSS, and OSV advisories. The box score's numbers (CVSS, EPSS, KEV status) are current as of Wednesday, August 19, 2026 UTC and are re-derived as the archive grows; only dated daily editions are immutable pages of record. The authoritative source for this identifier is cve.org.