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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-97416

btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk()

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: btrfs: balance: fix potential bg lookup failure in btrfs_may_alloc_data_chunk() [BUG] Running btrfs balance can trigger a null-ptr-deref before relocating a data chunk when metadata corruption leaves a chunk in the chunk tree without a corresponding block group in the in-memory cache: KASAN: null-ptr-deref in range [0x0000000000000088-0x000000000000008f] RIP: 0010:btrfs_may_alloc_data_chunk+0x40/0x1c0 fs/btrfs/volumes.c:3601 Call Trace: __btrfs_balance fs/btrfs/volumes.c:4217 [inline] btrfs_balance+0x2516/0x42b0 fs/btrfs/volumes.c:4604 btrfs_ioctl_balance fs/btrfs/ioctl.c:3577 [inline] btrfs_ioctl+0x25cf/0x5b90 fs/btrfs/ioctl.c:5313 ... [CAUSE] __btrfs_balance() iterates the on-disk chunk tree and passes the chunk logical bytenr to btrfs_may_alloc_data_chunk() before relocating a data chunk. That helper then queries the in-memory block group cache: cache = btrfs_lookup_block_group(fs_info, chunk_offset); chunk_type = cache->flags; /* cache may be NULL */ A corrupt image can contain a chunk item whose matching block group item is missing, so no block group is ever inserted into the cache. In that case btrfs_lookup_block_group() returns NULL. The code only guards this with ASSERT(cache), which becomes a no-op when CONFIG_BTRFS_ASSERT is disabled. The subsequent dereference of cache->flags therefore crashes the kernel. [FIX] Add a NULL check after btrfs_lookup_block_group() in btrfs_may_alloc_data_chunk() and print and error message for clarity.

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

  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 9f37a6d6ae9e998232e2ba091ab4999cdf967e1baffected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < e479236a8f4d85c4fb6b3f7c2556c21f583e2bf2affected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 322f891b4d4fe64acb3351a0ffa62a7fa5ba7256affected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 81a664ed8b1a44c76b204c4bd0d751317a02c5cdaffected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 9740dd0c17a4be8cc47a06c5ca5293471a7e286eaffected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 59f75e0c8724d4adebc08c7dd3ff2358b80c21f7affected
  • a6f93c71d412ba8ed743152c3a54ad0b78dcd9c7 to < 18d32b0013efba19f7ad3e5b08d7aee813d604a6affected

Linux Linux

Default version status: affected

  • 4.16affected
  • 0 to < 4.16unaffected
  • 5.10.271 to ≤ 5.10.*unaffected
  • 5.15.222 to ≤ 5.15.*unaffected
  • 6.1.189 to ≤ 6.1.*unaffected
  • 6.6.158 to ≤ 6.6.*unaffected
  • 6.12.111 to ≤ 6.12.*unaffected
  • 6.18.53 to ≤ 6.18.*unaffected
  • 7.2 to ≤ *unaffected

References