[patch net] sefltests: netdevsim: wait for devlink instance after netns removal

[patch net] sefltests: netdevsim: wait for devlink instance after netns removal

[Jiri Pirko]

From: Jiri Pirko <jiri@nvidia.com>

When devlink instance is put into network namespace and that network
namespace gets deleted, devlink instance is moved back into init_ns.
This is done as a part of cleanup_net() routine. Since cleanup_net()
is called asynchronously from workqueue, there is no guarantee that
the devlink instance move is done after "ip netns del" returns.

So fix this race by making sure that the devlink instance is present
before any other operation.

Reported-by: Amir Tzin <amirtz@nvidia.com>
Fixes: b74c37fd35a2 ("selftests: netdevsim: add tests for devlink reload with resources")
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
---
 .../selftests/drivers/net/netdevsim/devlink.sh | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
index a08c02abde12..7f7d20f22207 100755
--- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
+++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
@@ -17,6 +17,18 @@ SYSFS_NET_DIR=/sys/bus/netdevsim/devices/$DEV_NAME/net/
 DEBUGFS_DIR=/sys/kernel/debug/netdevsim/$DEV_NAME/
 DL_HANDLE=netdevsim/$DEV_NAME
 
+wait_for_devlink()
+{
+	"$@" | grep -q $DL_HANDLE
+}
+
+devlink_wait()
+{
+	local timeout=$1
+
+	busywait "$timeout" wait_for_devlink devlink dev
+}
+
 fw_flash_test()
 {
 	RET=0
@@ -256,6 +268,9 @@ netns_reload_test()
 	ip netns del testns2
 	ip netns del testns1
 
+	# Wait until netns async cleanup is done.
+	devlink_wait 2000
+
 	log_test "netns reload test"
 }
 
@@ -348,6 +363,9 @@ resource_test()
 	ip netns del testns2
 	ip netns del testns1
 
+	# Wait until netns async cleanup is done.
+	devlink_wait 2000
+
 	log_test "resource test"
 }
 
-- 
2.39.0

Re: [patch net] sefltests: netdevsim: wait for devlink instance after netns removal

[Pavan Chebbi]

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On Mon, Feb 20, 2023 at 6:54 PM Jiri Pirko <jiri@resnulli.us> wrote:
>
> From: Jiri Pirko <jiri@nvidia.com>
>
> When devlink instance is put into network namespace and that network
> namespace gets deleted, devlink instance is moved back into init_ns.
> This is done as a part of cleanup_net() routine. Since cleanup_net()
> is called asynchronously from workqueue, there is no guarantee that
> the devlink instance move is done after "ip netns del" returns.
>
> So fix this race by making sure that the devlink instance is present
> before any other operation.
>
> Reported-by: Amir Tzin <amirtz@nvidia.com>
> Fixes: b74c37fd35a2 ("selftests: netdevsim: add tests for devlink reload with resources")
> Signed-off-by: Jiri Pirko <jiri@nvidia.com>
> ---
>  .../selftests/drivers/net/netdevsim/devlink.sh | 18 ++++++++++++++++++
>  1 file changed, 18 insertions(+)
>
> diff --git a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
> index a08c02abde12..7f7d20f22207 100755
> --- a/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
> +++ b/tools/testing/selftests/drivers/net/netdevsim/devlink.sh
> @@ -17,6 +17,18 @@ SYSFS_NET_DIR=/sys/bus/netdevsim/devices/$DEV_NAME/net/
>  DEBUGFS_DIR=/sys/kernel/debug/netdevsim/$DEV_NAME/
>  DL_HANDLE=netdevsim/$DEV_NAME
>
> +wait_for_devlink()
> +{
> +       "$@" | grep -q $DL_HANDLE
> +}
> +
> +devlink_wait()
> +{
> +       local timeout=$1
> +
> +       busywait "$timeout" wait_for_devlink devlink dev
> +}
> +
>  fw_flash_test()
>  {
>         RET=0
> @@ -256,6 +268,9 @@ netns_reload_test()
>         ip netns del testns2
>         ip netns del testns1
>
> +       # Wait until netns async cleanup is done.
> +       devlink_wait 2000
> +
>         log_test "netns reload test"
>  }
>
> @@ -348,6 +363,9 @@ resource_test()
>         ip netns del testns2
>         ip netns del testns1
>
> +       # Wait until netns async cleanup is done.
> +       devlink_wait 2000
> +
>         log_test "resource test"
>  }
>
> --
> 2.39.0
>

Looks good to me.
Reviewed-by: Pavan Chebbi <pavan.chebbi@broadcom.com>

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Re: [patch net] sefltests: netdevsim: wait for devlink instance after netns removal

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (master)
by Paolo Abeni <pabeni@redhat.com>:

On Mon, 20 Feb 2023 14:23:36 +0100 you wrote:
> From: Jiri Pirko <jiri@nvidia.com>
> 
> When devlink instance is put into network namespace and that network
> namespace gets deleted, devlink instance is moved back into init_ns.
> This is done as a part of cleanup_net() routine. Since cleanup_net()
> is called asynchronously from workqueue, there is no guarantee that
> the devlink instance move is done after "ip netns del" returns.
> 
> [...]

Here is the summary with links:
  - [net] sefltests: netdevsim: wait for devlink instance after netns removal
    https://git.kernel.org/netdev/net/c/f922c7b1c1c4

You are awesome, thank you!
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