Re: [PATCH] dm-cache: fix NULL pointer dereference on open failure

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential
issue to consider:
- [Low] dm-cache: Fixes trailer cites c6b4fcbad044 instead of
  9b1cc9f251af
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commit 9e9ca29bfbdfdcf14064f5312fa72be5b8ba53a8
Author: Mikulas Patocka <mpatocka@redhat.com>

> dm-cache: fix NULL pointer dereference on open failure
>
> When __begin_transaction_flags in metadata_open fails,
> dm_cache_metadata_close is called. dm_cache_metadata_close attempts to
> execute list_del(&cmd->list);, but the "cmd" object is not on any list
> yet, thus it crashes with NULL pointer dereference.
>
> Fix this by initializing cmd->list after cmd is allocated.
>
> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
> Assisted-by: Claude:claude-opus-5
> Cc: stable@vger.kernel.org
> Fixes: c6b4fcbad044 ("dm: add cache target")

[Severity: Low]
Should the Fixes: tag reference 9b1cc9f251af ("dm cache: share
cache-metadata object across inactive and active DM tables") instead?

In c6b4fcbad044 ("dm: add cache target"), struct dm_cache_metadata did not
have a list member and dm_cache_metadata_close() did not call list_del().
Commit 9b1cc9f251af ("dm cache: share cache-metadata object across
inactive and active DM tables") added cmd->list, deferred list_add() to
lookup_or_open() after metadata_open() succeeds, and added
list_del(&cmd->list) to dm_cache_metadata_close().

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Sashiko AI review · https://sashiko.dev/#/patchset/05b79ec2-42f7-ffe3-20e6-1dc499e60cf5@redhat.com?part=1