[dm-devel] [PATCH v2 0/4] multipath: fixes for invalid path device handling

[Martin Wilck]

On Wed, 2019-02-13 at 16:55 -0600, Benjamin Marzinski wrote:
> I recently got a bug from a user with a bad property
> blacklist_exceptions line, where multipath tried to use a zram
> device,
> which caused multipathd to crash. This patch set fixes that crash,
> and
> then adds some additional safeguards to prevent things like this
> happening in the future.
> 
> The first patch fixes the crash. This crash could be triggered by any
> path device that isn't part of a multipath device, and has it's
> checker
> fail to check the path correctly.
> 
> The second patch blacklists zram devices specifically. The third
> patch
> fixes up some code weirdness that doesn't really cause any problems,
> aside from the messages it prints.
> 
> The fourth patch changes how pathinfo works so that it now drops
> devices
> of an unknown type if they can't get a wwid.  The biggest reason to
> do
> this is so that multipath won't hold an open file descriptor for
> these
> devices, which are almost definitely not multipathable (and
> occasionally
> send them TUR ioctls, which are bound to fail, since they aren't scsi
> devices).
> 
> As an aside, is there a good reason why multipath uses a devnode
> blacklist to individually blacklist device types, instead of
> blacklisting all denodes, and adding exceptions for the device types
> that we do support?
> 
> Changes in v2:
> use Martin Wilck's version of PATCH 1/4
> 
> Benjamin Marzinski (3):
>   multipath: blacklist zram devices
>   multipathd: fix pp->initialized state ping-ponging
>   multipathd: don't resend change events for unknown devices
> 
> Martin Wilck (1):
>   multipathd: avoid null pointer dereference in LOG_MSG
> 
>  libmultipath/blacklist.c   |  2 +-
>  libmultipath/checkers.c    |  9 +--------
>  libmultipath/checkers.h    |  6 +++++-
>  libmultipath/discovery.c   | 10 +++++++---
>  libmultipath/structs.h     |  1 +
>  multipath/multipath.conf.5 |  2 +-
>  multipathd/main.c          | 10 +++++++---
>  7 files changed, 23 insertions(+), 17 deletions(-)
> 

For the set:
Reviewed-by: Martin Wilck <mwilck at suse.com>