[dm-devel] [PATCH] kobj_uevent: Ignore if some listeners cannot handle message

[Eric W. Biederman]

Milan Broz <mbroz at redhat.com> writes:

> kobject_uevent() uses a multicast socket and should ignore
> if one of listeners cannot handle messages or nobody is
> listening at all.
>
> Easily reproducible when a process in system is cloned
> with CLONE_NEWNET flag.
>
> (See also
> http://article.gmane.org/gmane.linux.kernel.device-mapper.dm-crypt/5256)

I am fine with the patch below.

However if you are fine with the patch below let's just remove the
return code from code from kobject_uevent_env.  We are now explicitly
ignoring all of the possible return codes from
netlink_broadcast_filtered.  

Ignoring all of the return codes from netlink_broadcast_filtered ignores
all of the expected errors from kobject_uevent_env, short of programmer
error.

So why have an error code on kobject_uevent_env?

> Signed-off-by: Milan Broz <mbroz at redhat.com>
> ---
>  lib/kobject_uevent.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c
> index 70af0a7..ad72a03 100644
> --- a/lib/kobject_uevent.c
> +++ b/lib/kobject_uevent.c
> @@ -282,7 +282,7 @@ int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
>  							    kobj_bcast_filter,
>  							    kobj);
>  			/* ENOBUFS should be handled in userspace */
> -			if (retval == -ENOBUFS)
> +			if (retval == -ENOBUFS || retval == -ESRCH)
>  				retval = 0;
>  		} else
>  			retval = -ENOMEM;