ACK: [PATCH 0/2][SRU][F] systemd mount units fail during boot, while file system is correctly mounted

[Tim Gardner]

On 8/10/23 11:04 AM, Heitor Alves de Siqueira wrote:
> BugLink: https://bugs.launchpad.net/bugs/1837227
> 
> Hi kernel-team,
> 
> Users have reported systemd mount failures causing their systems to boot into
> emergency mode, even though the file systems seem to be correctly mounted. This
> is fixed by the systemd commit mentioned below, but it has a hard-dependency on
> cursor support for /proc/mounts.
> 
> I've cherry-picked two kernel patches that are necessary for this to work: the
> list_for_each_continue() patch isn't a hard requirement, but including it makes
> the cursor patch apply cleanly with minimal offset changes. We've had affected
> users test these kernel commits independently of a fixed systemd package, and
> they haven't reported any issues on their own (i.e. these patches shouldn't
> break the kernel on non-patched systemd builds, and vice versa).
> 
> The kernel commits were introduced in v5.6 and v5.8, so releases newer than
> Focal are already fixed.
> 
> [Impact]
>   * systemd mount units fail during boot, and the system boots into emergency mode
>   * caused by systemd not handling mounts that are MOUNT_MOUNTING when receiving signals
> 
> [Fix]
>   * Fixed by systemd patch:
>     - 01400460ae16 core/mount: adjust deserialized state based on /proc/self/mountinfo
>   * Fixed by kernel patch:
>     - 9f6c61f96f2d proc/mounts: add cursor
> 
> [Test Case]
>    * Using rep-tmpfs.sh script from BugLink, no failures should be reported for all test variants
> 
> Miklos Szeredi (1):
>    proc/mounts: add cursor
> 
> Pavel Begunkov (1):
>    list: introduce list_for_each_continue()
> 
>   fs/mount.h            | 12 ++++--
>   fs/namespace.c        | 91 +++++++++++++++++++++++++++++++++++--------
>   fs/proc_namespace.c   |  4 +-
>   include/linux/list.h  | 10 +++++
>   include/linux/mount.h |  4 +-
>   5 files changed, 100 insertions(+), 21 deletions(-)
> 
Acked-by: Tim Gardner <tim.gardner at canonical.com>
-- 
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Tim Gardner
Canonical, Inc