[PATCH] mlxsw: core: Fix an error handling path in 'mlxsw_core_bus_device_register()'

[PATCH] mlxsw: core: Fix an error handling path in 'mlxsw_core_bus_device_register()'

[Christophe JAILLET]

Resources are not freed in the reverse order of the allocation.
Labels are also mixed-up.

Fix it and reorder code and labels in the error handling path of
'mlxsw_core_bus_device_register()'

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
Please review carefully. This patch is proposed because it triggers one of
my coccinelle scripts. I'm not 100% sure if correct.

The script tries to spot wrongly ordered error handling path. It is:
@@
identifier l1, l2;
@@

   if (...) {
      ...
*     goto l1;
   }
   ...
   if (...) {
      ...
*     goto l2;
   }
   ...
*l1:
   ...
*l2:
   ...
---
 drivers/net/ethernet/mellanox/mlxsw/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/core.c b/drivers/net/ethernet/mellanox/mlxsw/core.c
index 93ea56620a24..e13ac3b8dff7 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/core.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/core.c
@@ -1100,11 +1100,11 @@ int mlxsw_core_bus_device_register(const struct mlxsw_bus_info *mlxsw_bus_info,
 err_alloc_lag_mapping:
 	mlxsw_ports_fini(mlxsw_core);
 err_ports_init:
-	mlxsw_bus->fini(bus_priv);
-err_bus_init:
 	if (!reload)
 		devlink_resources_unregister(devlink, NULL);
 err_register_resources:
+	mlxsw_bus->fini(bus_priv);
+err_bus_init:
 	if (!reload)
 		devlink_free(devlink);
 err_devlink_alloc:
-- 
2.17.0

Re: [PATCH] mlxsw: core: Fix an error handling path in 'mlxsw_core_bus_device_register()'

[Ido Schimmel]

On Thu, May 10, 2018 at 01:26:16PM +0200, Christophe JAILLET wrote:
> Resources are not freed in the reverse order of the allocation.
> Labels are also mixed-up.
> 
> Fix it and reorder code and labels in the error handling path of
> 'mlxsw_core_bus_device_register()'
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>

For net:

Fixes: ef3116e5403e ("mlxsw: spectrum: Register KVD resources with devlink")
Reviewed-by: Ido Schimmel <idosch@mellanox.com>

Next time, please indicate the tree you're targeting as explained here:
https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt

And include a Fixes line as explained here:
https://www.kernel.org/doc/Documentation/process/submitting-patches.rst

Thanks!

Re: [PATCH] mlxsw: core: Fix an error handling path in 'mlxsw_core_bus_device_register()'

[David Miller]

From: Ido Schimmel <idosch@idosch.org>
Date: Thu, 10 May 2018 14:58:21 +0300

> On Thu, May 10, 2018 at 01:26:16PM +0200, Christophe JAILLET wrote:
>> Resources are not freed in the reverse order of the allocation.
>> Labels are also mixed-up.
>> 
>> Fix it and reorder code and labels in the error handling path of
>> 'mlxsw_core_bus_device_register()'
>> 
>> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> 
> For net:
> 
> Fixes: ef3116e5403e ("mlxsw: spectrum: Register KVD resources with devlink")
> Reviewed-by: Ido Schimmel <idosch@mellanox.com>

Applied and queued up for -stable, thanks.

Re: [PATCH] mlxsw: core: Fix an error handling path in 'mlxsw_core_bus_device_register()'

[Dan Carpenter]

On Thu, May 10, 2018 at 01:26:16PM +0200, Christophe JAILLET wrote:
> Resources are not freed in the reverse order of the allocation.
> Labels are also mixed-up.
> 
> Fix it and reorder code and labels in the error handling path of
> 'mlxsw_core_bus_device_register()'
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> Please review carefully. This patch is proposed because it triggers one of
> my coccinelle scripts. I'm not 100% sure if correct.
> 

Looks correct.

The err = mlxsw_driver->resources_register(mlxsw_core); pointer is a
pointer to mlxsw_sp_resources_register().  That function doesn't clean
up after itself on failure.  Ideally, you'd want a matching
mlxsw_driver->resources_unregister as well pointer instead of hard
coding devlink_resources_unregister().

The error handling would be easier to review if the gotos told you what
the did.  Right now they're written in "come from" style so the tell you
what happened on the line before.

	if (!foo)
		goto allocating_foo_failed;

Hopefully if someone fixes mlxsw_sp_resources_register() they'll choose
better label names.

regards,
dan carpenter