nvmet-fcloop: call done callback even when remote port is gone

[PATCH] nvmet-fcloop: call done callback even when remote port is gone

Posted by Daniel Wagner 1 month ago

When the target port is gone, it's not possible to access any of the
request resources. The function should just silently drop the response.
The comment is misleading in this regard.

Though it's still necessary to call the driver via the ->done callback
so the driver is able to release all resources.

Reported-by: Yi Zhang <yi.zhang@redhat.com>
Closes: https://lore.kernel.org/all/CAHj4cs-OBA0WMt5f7R0dz+rR4HcEz19YLhnyGsj-MRV3jWDsPg@mail.gmail.com/
Fixes: 84eedced1c5b ("nvmet-fcloop: drop response if targetport is gone")
Signed-off-by: Daniel Wagner <wagi@kernel.org>
---
 drivers/nvme/target/fcloop.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index 257b497d515a892a39da82d2f96b3fa3c6e10cdd..5dffcc5becae86c79ef75a123647566b2dfc21f6 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -496,13 +496,15 @@ fcloop_t2h_xmt_ls_rsp(struct nvme_fc_local_port *localport,
 	if (!targetport) {
 		/*
 		 * The target port is gone. The target doesn't expect any
-		 * response anymore and the ->done call is not valid
-		 * because the resources have been freed by
-		 * nvmet_fc_free_pending_reqs.
+		 * response anymore and thus lsreq can't be accessed anymore.
 		 *
 		 * We end up here from delete association exchange:
 		 * nvmet_fc_xmt_disconnect_assoc sends an async request.
+		 *
+		 * Return success because this is what LLDDs do; silently
+		 * drop the response.
 		 */
+		lsrsp->done(lsrsp);
 		kmem_cache_free(lsreq_cache, tls_req);
 		return 0;
 	}

---
base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
change-id: 20250901-nvme-fc-fix-leaks-4a25ca3875ab

Best regards,
-- 
Daniel Wagner <wagi@kernel.org>

Re: [PATCH] nvmet-fcloop: call done callback even when remote port is gone

Posted by Yi Zhang 1 month ago

On Mon, Sep 1, 2025 at 11:58 PM Daniel Wagner <wagi@kernel.org> wrote:
>
> When the target port is gone, it's not possible to access any of the
> request resources. The function should just silently drop the response.
> The comment is misleading in this regard.
>
> Though it's still necessary to call the driver via the ->done callback
> so the driver is able to release all resources.
>
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Closes: https://lore.kernel.org/all/CAHj4cs-OBA0WMt5f7R0dz+rR4HcEz19YLhnyGsj-MRV3jWDsPg@mail.gmail.com/
> Fixes: 84eedced1c5b ("nvmet-fcloop: drop response if targetport is gone")
> Signed-off-by: Daniel Wagner <wagi@kernel.org>
> ---
>  drivers/nvme/target/fcloop.c | 8 +++++---
>  1 file changed, 5 insertions(+), 3 deletions(-)
>

Verified the kmemleak issue fixed with this patch:

Tested-by: Yi Zhang <yi.zhang@redhat.com>

> diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
> index 257b497d515a892a39da82d2f96b3fa3c6e10cdd..5dffcc5becae86c79ef75a123647566b2dfc21f6 100644
> --- a/drivers/nvme/target/fcloop.c
> +++ b/drivers/nvme/target/fcloop.c
> @@ -496,13 +496,15 @@ fcloop_t2h_xmt_ls_rsp(struct nvme_fc_local_port *localport,
>         if (!targetport) {
>                 /*
>                  * The target port is gone. The target doesn't expect any
> -                * response anymore and the ->done call is not valid
> -                * because the resources have been freed by
> -                * nvmet_fc_free_pending_reqs.
> +                * response anymore and thus lsreq can't be accessed anymore.
>                  *
>                  * We end up here from delete association exchange:
>                  * nvmet_fc_xmt_disconnect_assoc sends an async request.
> +                *
> +                * Return success because this is what LLDDs do; silently
> +                * drop the response.
>                  */
> +               lsrsp->done(lsrsp);
>                 kmem_cache_free(lsreq_cache, tls_req);
>                 return 0;
>         }
>
> ---
> base-commit: b320789d6883cc00ac78ce83bccbfe7ed58afcf0
> change-id: 20250901-nvme-fc-fix-leaks-4a25ca3875ab
>
> Best regards,
> --
> Daniel Wagner <wagi@kernel.org>
>


-- 
Best Regards,
  Yi Zhang

Re: [PATCH] nvmet-fcloop: call done callback even when remote port is gone

Posted by Hannes Reinecke 1 month ago

On 9/1/25 17:51, Daniel Wagner wrote:
> When the target port is gone, it's not possible to access any of the
> request resources. The function should just silently drop the response.
> The comment is misleading in this regard.
> 
> Though it's still necessary to call the driver via the ->done callback
> so the driver is able to release all resources.
> 
> Reported-by: Yi Zhang <yi.zhang@redhat.com>
> Closes: https://lore.kernel.org/all/CAHj4cs-OBA0WMt5f7R0dz+rR4HcEz19YLhnyGsj-MRV3jWDsPg@mail.gmail.com/
> Fixes: 84eedced1c5b ("nvmet-fcloop: drop response if targetport is gone")
> Signed-off-by: Daniel Wagner <wagi@kernel.org>
> ---
>   drivers/nvme/target/fcloop.c | 8 +++++---
>   1 file changed, 5 insertions(+), 3 deletions(-)
> 
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich