U.S. flag   An official website of the United States government
Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Https

Secure .gov websites use HTTPS
A lock (Dot gov) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.

Vulnerability Change Records for CVE-2021-47493

Change History

New CVE Received by NIST 5/22/2024 5:15:11 AM

Action Type Old Value New Value
Added 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.
Added Reference

								
							
							
						
kernel.org https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2 [No types assigned]
Added Reference

								
							
							
						
kernel.org https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7 [No types assigned]
Added Reference

								
							
							
						
kernel.org https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558 [No types assigned]