[PATCH] acpi: fix for memory leak in i2c_acpi_install_space_handler

[PATCH] acpi: fix for memory leak in i2c_acpi_install_space_handler

[Vamshi K Sthambamkadi]

kmemleak reported backtrace:
    [<bbee0454>] kmem_cache_alloc_trace+0x128/0x260
    [<6677f215>] i2c_acpi_install_space_handler+0x4b/0xe0
    [<1180f4fc>] i2c_register_adapter+0x186/0x400
    [<6083baf7>] i2c_add_adapter+0x4e/0x70
    [<a3ddf966>] intel_gmbus_setup+0x1a2/0x2c0 [i915]
    [<84cb69ae>] i915_driver_probe+0x8d8/0x13a0 [i915]
    [<81911d4b>] i915_pci_probe+0x48/0x160 [i915]
    [<4b159af1>] pci_device_probe+0xdc/0x160
    [<b3c64704>] really_probe+0x1ee/0x450
    [<bc029f5a>] driver_probe_device+0x142/0x1b0
    [<d8829d20>] device_driver_attach+0x49/0x50
    [<de71f045>] __driver_attach+0xc9/0x150
    [<df33ac83>] bus_for_each_dev+0x56/0xa0
    [<80089bba>] driver_attach+0x19/0x20
    [<cc73f583>] bus_add_driver+0x177/0x220
    [<7b29d8c7>] driver_register+0x56/0xf0
In i2c_acpi_remove_space_handler function, leak occurs whenever "data"
parameter is initialized to 0 in call to acpi_bus_get_private_data().
This is because the parameter validity check in acpi_bus_get_private_data
(condition->if(!*data)) returns EINVAL and as a consequence, memory is
never freed in i2c_acpi_remove_space_handler function. Fix/Correct the
parameter validity check in acpi_bus_get_private_data() as that of
similarly done in acpi_get_data_full().

Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
---
 drivers/acpi/bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index 48bc96d..5400267 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -153,7 +153,7 @@ int acpi_bus_get_private_data(acpi_handle handle, void **data)
 {
 	acpi_status status;
 
-	if (!*data)
+	if (!data)
 		return -EINVAL;
 
 	status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
-- 
2.7.4

Re: [PATCH] acpi: fix for memory leak in i2c_acpi_install_space_handler

[Rafael J. Wysocki]

On Thursday, November 28, 2019 11:28:29 AM CET Vamshi K Sthambamkadi wrote:
> kmemleak reported backtrace:
>     [<bbee0454>] kmem_cache_alloc_trace+0x128/0x260
>     [<6677f215>] i2c_acpi_install_space_handler+0x4b/0xe0
>     [<1180f4fc>] i2c_register_adapter+0x186/0x400
>     [<6083baf7>] i2c_add_adapter+0x4e/0x70
>     [<a3ddf966>] intel_gmbus_setup+0x1a2/0x2c0 [i915]
>     [<84cb69ae>] i915_driver_probe+0x8d8/0x13a0 [i915]
>     [<81911d4b>] i915_pci_probe+0x48/0x160 [i915]
>     [<4b159af1>] pci_device_probe+0xdc/0x160
>     [<b3c64704>] really_probe+0x1ee/0x450
>     [<bc029f5a>] driver_probe_device+0x142/0x1b0
>     [<d8829d20>] device_driver_attach+0x49/0x50
>     [<de71f045>] __driver_attach+0xc9/0x150
>     [<df33ac83>] bus_for_each_dev+0x56/0xa0
>     [<80089bba>] driver_attach+0x19/0x20
>     [<cc73f583>] bus_add_driver+0x177/0x220
>     [<7b29d8c7>] driver_register+0x56/0xf0
> In i2c_acpi_remove_space_handler function, leak occurs whenever "data"
> parameter is initialized to 0 in call to acpi_bus_get_private_data().
> This is because the parameter validity check in acpi_bus_get_private_data
> (condition->if(!*data)) returns EINVAL and as a consequence, memory is
> never freed in i2c_acpi_remove_space_handler function. Fix/Correct the
> parameter validity check in acpi_bus_get_private_data() as that of
> similarly done in acpi_get_data_full().
> 
> Signed-off-by: Vamshi K Sthambamkadi <vamshi.k.sthambamkadi@gmail.com>
> ---
>  drivers/acpi/bus.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> index 48bc96d..5400267 100644
> --- a/drivers/acpi/bus.c
> +++ b/drivers/acpi/bus.c
> @@ -153,7 +153,7 @@ int acpi_bus_get_private_data(acpi_handle handle, void **data)
>  {
>  	acpi_status status;
>  
> -	if (!*data)
> +	if (!data)
>  		return -EINVAL;
>  
>  	status = acpi_get_data(handle, acpi_bus_private_data_handler, data);
> 

Applying as a stable-candidate fix for 5.5 with rewritten subject and changelog.

Thanks!