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CVE PROGRAM SOURCE RECORD7.8 High

CVE-2025-37856

btrfs: harden block_group::bg_list against list_del() races

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: harden block_group::bg_list against list_del() races As far as I can tell, these calls of list_del_init() on bg_list cannot run concurrently with btrfs_mark_bg_unused() or btrfs_mark_bg_to_reclaim(), as they are in transaction error paths and situations where the block group is readonly. However, if there is any chance at all of racing with mark_bg_unused(), or a different future user of bg_list, better to be safe than sorry. Otherwise we risk the following interleaving (bg_list refcount in parens) T1 (some random op) T2 (btrfs_mark_bg_unused) !list_empty(&bg->bg_list); (1) list_del_init(&bg->bg_list); (1) list_move_tail (1) btrfs_put_block_group (0) btrfs_delete_unused_bgs bg = list_first_entry list_del_init(&bg->bg_list); btrfs_put_block_group(bg); (-1) Ultimately, this results in a broken ref count that hits zero one deref early and the real final deref underflows the refcount, resulting in a WARNING.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • 01eca70ef8cf499d0cb6d1bbd691558e7792cf17 to < ccb20413e7c82e4429c81f10d0e36cd9c0c643cdaffected
  • a9f189716cf15913c453299d72f69c51a9b0f86b to < 9039afe6240ae01d6caf2fa731590ac74fb8a69baffected
  • a9f189716cf15913c453299d72f69c51a9b0f86b to < bf089c4d1141b27332c092b1dcca5022c415a3b6affected
  • a9f189716cf15913c453299d72f69c51a9b0f86b to < 909e60fb469d4101c6b08cf6e622efb062bb24a1affected
  • a9f189716cf15913c453299d72f69c51a9b0f86b to < 185fd73e5ac06027c4be9a129e59193f6a3ef202affected
  • a9f189716cf15913c453299d72f69c51a9b0f86b to < 7511e29cf1355b2c47d0effb39e463119913e2f6affected
  • edf3b5aadb2515c808200b904baa5b70a727f0acaffected
  • 5d19abcffd8404078dfa7d7118cec357b5e7bc58affected
  • 6.1.47 to < 6.1.191affected
  • 5.15.128 to < 5.16affected
  • 6.4.12 to < 6.5affected

Linux Linux

Default version status: affected

  • 6.5affected
  • 0 to < 6.5unaffected
  • 6.1.191 to ≤ 6.1.*unaffected
  • 6.6.160 to ≤ 6.6.*unaffected
  • 6.12.24 to ≤ 6.12.*unaffected
  • 6.13.12 to ≤ 6.13.*unaffected
  • 6.14.3 to ≤ 6.14.*unaffected
  • 6.15 to ≤ *unaffected

References