CVE-2022-49761

In the Linux kernel, the following vulnerability has been resolved:

btrfs: always report error in run_one_delayed_ref()

Currently we have a btrfs_debug() for run_one_delayed_ref() failure, but if end users hit such problem, there will be no chance that btrfs_debug() is enabled. This can lead to very little useful info for debugging.

This patch will:

• Add extra info for error reporting Including:

  • logical bytenr
  • num_bytes
  • type
  • action
  • ref_mod

• Replace the btrfs_debug() with btrfs_err()

• Move the error reporting into run_one_delayed_ref() This is to avoid use-after-free, the @node can be freed in the caller.

This error should only be triggered at most once.

As if run_one_delayed_ref() failed, we trigger the error message, then causing the call chain to error out:

btrfs_run_delayed_refs() - btrfs_run_delayed_refs() - btrfs_run_delayed_refs_for_head() `- run_one_delayed_ref()

And we will abort the current transaction in btrfs_run_delayed_refs(). If we have to run delayed refs for the abort transaction, run_one_delayed_ref() will just cleanup the refs and do nothing, thus no new error messages would be output.