CVE-2021-47493

  1. OpenCVE
  2. Vulnerabilities (CVE)
  3. CVE-2021-47493
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.

4.7 /10

CVSS v3 : MEDIUM

V3 Legend

Vector :

Exploitability : 1.0 / Impact : 3.6

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References
Link Resource
https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 Patch
https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 Patch
https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 Patch
https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 Patch
https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 Patch
https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 Patch
Configurations

Configuration 1 (hide)

OR cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:*
History

24 Sep 2025, 19:11

Type Values Removed Values Added
CVSS v2 : unknown
v3 : unknown 		v2 : unknown
v3 : 4.7
CWE CWE-362
CPE cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
References () https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 - () https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 - Patch
References () https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 - () https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 - Patch
References () https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 - () https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 - Patch
First Time Linux
Linux linux Kernel

21 Nov 2024, 06:36

Type Values Removed Values Added
References () https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 - () https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 -
References () https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 - () https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 -
References () https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 - () https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 -
Summary
  • (es) En el kernel de Linux, se resolvió la siguiente vulnerabilidad: ocfs2: corrige la ejecución entre fragmentos de búsqueda y libera journal_head de buffer_head Se encontró una ejecución entre ocfs2_test_bg_bit_allocatable() y jbd2_journal_put_journal_head() que resultó en el siguiente vmcore. PID: 106879 TAREA: ffff880244ba9c00 CPU: 2 COMANDO: "loop3" Rastreo de llamadas: pánico oops_end no_context __bad_area_nosemaphore bad_area_nosemaphore __do_page_fault do_page_fault page_fault [excepción RIP: ocfs2_block_group_find_clear_bits+316] 2_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] 2_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 Cuando ocfs2_test_bg_bit_allocatable () llamado bh2jh(bg_bh), el bg_bh->b_private NULL como jbd2_journal_put_journal_head() corrió y liberó el encabezado del diario del encabezado del búfer. Era necesario bloquear el bit 'BH_JournalHead' para solucionar esta ejecución.

22 May 2024, 09:15

Type Values Removed Values Added
New CVE
Information

Published : 2024-05-22 09:15

Updated : 2025-09-24 19:11

NVD link : CVE-2021-47493

Mitre link : CVE-2021-47493

CVE.ORG link : CVE-2021-47493

JSON object : View

Products Affected

linux

  • linux_kernel
CWE
CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')