Subject: Re: [PATCH ipsec-next v5 7/8] xfrm: add error messages to state migration

From: Sabrina Dubroca <[email-masked]>
Date: Fri, 30 Jan 2026 13:14:39 +0100

2026-01-27, 11:43:42 +0100, Antony Antony wrote:
> Add descriptive(extack) error messages for all error paths
> in state migration. This improves diagnostics by
> providing clear feedback when migration fails.
> 
> Signed-off-by: Antony Antony <[email-masked]>
> ---
> v4->v5: - added this patch
> ---
>  net/xfrm/xfrm_state.c | 13 ++++++++++---
>  1 file changed, 10 insertions(+), 3 deletions(-)
> 
> diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c
> index 88a362e46972..2e03871ae872 100644
> --- a/net/xfrm/xfrm_state.c
> +++ b/net/xfrm/xfrm_state.c
> @@ -2129,15 +2129,21 @@ struct xfrm_state *xfrm_state_migrate_create(struct xfrm_state *x,
>  	struct xfrm_state *xc;
> 
>  	xc = xfrm_state_clone_and_setup(x, encap, m);
> -	if (!xc)
> +	if (!xc) {
> +		NL_SET_ERR_MSG(extack, "Failed to clone and setup state");

When xfrm_state_clone_and_setup fails it's because some allocation
failed and the user won't be able to do much about this, right? I
don't feel extack in those situations is super helpful.

>  		return NULL;
> +	}
> 
> -	if (xfrm_init_state(xc) < 0)
> +	if (xfrm_init_state(xc) < 0) {
> +		NL_SET_ERR_MSG(extack, "Failed to initialize migrated state");

xfrm_init_state itself doesn't handle extack, but it's just a wrapper
around functions that do. Maybe better to make xfrm_init_state
propagate extack?

>  		goto error;
> +	}
> 
>  	/* configure the hardware if offload is requested */
> -	if (xuo && xfrm_dev_state_add(net, xc, xuo, extack))
> +	if (xuo && xfrm_dev_state_add(net, xc, xuo, extack)) {
> +		NL_SET_ERR_MSG(extack, "Failed to initialize state offload");

We already set an extack in xfrm_dev_state_add, this chunk should be
dropped to avoid overwriting the more specific info we got.

>  		goto error;
> +	}
> 
>  	return xc;
>  error:
> @@ -2161,6 +2167,7 @@ int xfrm_state_migrate_install(const struct xfrm_state *x,
>  		xfrm_state_insert(xc);
>  	} else {
>  		if (xfrm_state_add(xc) < 0) {
> +			NL_SET_ERR_MSG(extack, "Failed to add migrated state");

Not a strong objection, but this case would be the EEXIST situation
from xfrm_state_add, and there's not much the user can do about this?

>  			if (xuo)
>  				xfrm_dev_state_delete(xc);
>  			xc->km.state = XFRM_STATE_DEAD;

-- 
Sabrina