Re: [regression 6.1.67] dlm: cannot start dlm midcomms -97 after backport of e9cdebbe23f1 ("dlm: use kernel_connect() and kernel_bind()")

[Jordan Rife]

On Wed, Feb 7, 2024 at 2:39 AM Salvatore Bonaccorso <carnil@xxxxxxxxxx> wrote:
>
> Hi Valentin, hi all
>
> [This is about a regression reported in Debian for 6.1.67]
>
> On Tue, Feb 06, 2024 at 01:00:11PM +0100, Valentin Kleibel wrote:
> > Package: linux-image-amd64
> > Version: 6.1.76+1
> > Source: linux
> > Source-Version: 6.1.76+1
> > Severity: important
> > Control: notfound -1 6.6.15-2
> >
> > Dear Maintainers,
> >
> > We discovered a bug affecting dlm that prevents any tcp communications by
> > dlm when booted with debian kernel 6.1.76-1.
> >
> > Dlm startup works (corosync-cpgtool shows the dlm:controld group with all
> > expected nodes) but as soon as we try to add a lockspace dmesg shows:
> > ```
> > dlm: Using TCP for communications
> > dlm: cannot start dlm midcomms -97
> > ```
> >
> > It seems that commit "dlm: use kernel_connect() and kernel_bind()"
> > (e9cdebbe) was merged to 6.1.
> >
> > Checking the code it seems that the changed function dlm_tcp_listen_bind()
> > fails with exit code 97 (EAFNOSUPPORT)
> > It is called from
> >
> > dlm/lockspace.c: threads_start() -> dlm_midcomms_start()
> > dlm/midcomms.c: dlm_midcomms_start() -> dlm_lowcomms_start()
> > dlm/lowcomms.c: dlm_lowcomms_start() -> dlm_listen_for_all() ->
> > dlm_proto_ops->listen_bind() = dlm_tcp_listen_bind()
> >
> > The error code is returned all the way to threads_start() where the error
> > message is emmitted.
> >
> > Booting with the unsigned kernel from testing (6.6.15-2), which also
> > contains this commit, works without issues.
> >
> > I'm not sure what additional changes are required to get this working or if
> > rolling back this change is an option.
> >
> > We'd be happy to test patches that might fix this issue.
>
> Thanks for your report. So we have a 6.1.76 specific regression for
> the backport of e9cdebbe23f1 ("dlm: use kernel_connect() and
> kernel_bind()") .
>
> Let's loop in the upstream regression list for tracking and people
> involved for the subsystem to see if the issue can be identified. As
> it is working for 6.6.15 which includes the commit backport as well it
> might be very well that a prerequisite is missing.
>
> # annotate regression with 6.1.y specific commit
> #regzbot ^introduced e11dea8f503341507018b60906c4a9e7332f3663
> #regzbot link: https://bugs.debian.org/1063338
>
> Any ideas?
>
> Regards,
> Salvatore


Just a quick look comparing dlm_tcp_listen_bind between the latest 6.1
and 6.6 stable branches,
it looks like there is a mismatch here with the dlm_local_addr[0] parameter.

6.1
----

static int dlm_tcp_listen_bind(struct socket *sock)
{
int addr_len;

/* Bind to our port */
make_sockaddr(dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0],
   addr_len);
}

6.6
----
static int dlm_tcp_listen_bind(struct socket *sock)
{
int addr_len;

/* Bind to our port */
make_sockaddr(&dlm_local_addr[0], dlm_config.ci_tcp_port, &addr_len);
return kernel_bind(sock, (struct sockaddr *)&dlm_local_addr[0],
   addr_len);
}

6.6 contains commit c51c9cd8 (fs: dlm: don't put dlm_local_addrs on heap) which
changed

static struct sockaddr_storage *dlm_local_addr[DLM_MAX_ADDR_COUNT];

to

static struct sockaddr_storage dlm_local_addr[DLM_MAX_ADDR_COUNT];

It looks like kernel_bind() in 6.1 needs to be modified to match.


-Jordan