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PUBLISHED

CVE-2021-47493

ocfs2: fix race between searching chunks and release journal_head from buffer_head

Assigner:Linux (416baaa9-dc9f-4396-8d5f-8c081fb06d67)
Reserved:2024-05-22
Published:2024-05-22
Updated:2024-06-06

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.

Product status

Default status
unaffected

1da177e4c3f4 before 5043fbd294f5
affected

1da177e4c3f4 before 2e382600e885
affected

1da177e4c3f4 before 6f1b228529ae
affected

Default status
affected

5.10.77
unaffected

5.14.16
unaffected

5.15
unaffected

References

https://git.kernel.org/stable/c/5043fbd294f5909a080ade0f04b70a4da9e122b7

https://git.kernel.org/stable/c/2e382600e8856ea654677b5134ee66e03ea72bc2

https://git.kernel.org/stable/c/6f1b228529ae49b0f85ab89bcdb6c365df401558

cve.org CVE-2021-47493

nvd.nist.gov CVE-2021-47493

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