This driver was directly calling __devm_request_region with a specific
resource on the stack as parameter. This is invalid as
__devm_request_region expects the given resource passed as parameter
to live longer than the call itself, as the pointer to the resource
will be stored inside the internal struct used by the devres
management.
In addition to this issue, a related bug has been found by kmemleak
with this trace :
unreferenced object 0xc0000001efc01880 (size 64):
comm "swapper/0", pid 1, jiffies 4294669078 (age 3620.536s)
hex dump (first 32 bytes):
00 00 00 0f fe 4a c0 00 00 00 00 0f fe 4a cf ff .....J.......J..
c0 00 00 00 00 ee 9d 98 00 00 00 00 80 00 02 00 ................
backtrace:
[<c000000000078874>] .alloc_resource+0xb8/0xe0
[<c000000000079b50>] .__request_region+0x70/0x1c4
[<c00000000007a010>] .__devm_request_region+0x8c/0x138
[<c0000000006e0dc8>] .fman_port_probe+0x170/0x420
[<c0000000005cecb8>] .platform_drv_probe+0x84/0x108
[<c0000000005cc620>] .driver_probe_device+0x2c4/0x394
[<c0000000005cc814>] .__driver_attach+0x124/0x128
[<c0000000005c9ad4>] .bus_for_each_dev+0xb4/0x110
[<c0000000005cca1c>] .driver_attach+0x34/0x4c
[<c0000000005ca9b0>] .bus_add_driver+0x264/0x2a4
[<c0000000005cd9e0>] .driver_register+0x94/0x160
[<c0000000005cfea4>] .__platform_driver_register+0x60/0x7c
[<c000000000f86a00>] .fman_port_load+0x28/0x64
[<c000000000f4106c>] .do_one_initcall+0xd4/0x1a8
[<c000000000f412fc>] .kernel_init_freeable+0x1bc/0x2a4
[<c00000000000180c>] .kernel_init+0x24/0x138
Indeed, the new resource (created in __request_region) will be linked
to the given resource living on the stack, which will end its lifetime
after the function calling __devm_request_region has finished.
Meaning the new resource allocated is no longer reachable.
Now that the main fman driver is no longer reserving the region
used by fman-port, this previous hack is no longer needed
and we can use the regular call to devm_request_mem_region instead,
solving those bugs at the same time.
Signed-off-by: Patrick Havelange <[email protected]>
---
drivers/net/ethernet/freescale/fman/fman_port.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/freescale/fman/fman_port.c b/drivers/net/ethernet/freescale/fman/fman_port.c
index d9baac0dbc7d..354974939d9d 100644
--- a/drivers/net/ethernet/freescale/fman/fman_port.c
+++ b/drivers/net/ethernet/freescale/fman/fman_port.c
@@ -1878,10 +1878,10 @@ static int fman_port_probe(struct platform_device *of_dev)
of_node_put(port_node);
- dev_res = __devm_request_region(port->dev, &res, res.start,
- resource_size(&res), "fman-port");
+ dev_res = devm_request_mem_region(port->dev, res.start,
+ resource_size(&res), "fman-port");
if (!dev_res) {
- dev_err(port->dev, "%s: __devm_request_region() failed\n",
+ dev_err(port->dev, "%s: devm_request_mem_region() failed\n",
__func__);
err = -EINVAL;
goto free_port;
--
2.17.1
> -----Original Message-----
> From: Patrick Havelange <[email protected]>
> Sent: 02 December 2020 18:16
> To: Madalin Bucur <[email protected]>; David S. Miller
> <[email protected]>; Jakub Kicinski <[email protected]>;
> [email protected]; [email protected]
> Cc: Patrick Havelange <[email protected]>
> Subject: [PATCH 2/4] net: freescale/fman-port: remove direct use of
> __devm_request_region
>
> This driver was directly calling __devm_request_region with a specific
> resource on the stack as parameter. This is invalid as
> __devm_request_region expects the given resource passed as parameter
> to live longer than the call itself, as the pointer to the resource
> will be stored inside the internal struct used by the devres
> management.
>
> In addition to this issue, a related bug has been found by kmemleak
> with this trace :
> unreferenced object 0xc0000001efc01880 (size 64):
> comm "swapper/0", pid 1, jiffies 4294669078 (age 3620.536s)
> hex dump (first 32 bytes):
> 00 00 00 0f fe 4a c0 00 00 00 00 0f fe 4a cf ff .....J.......J..
> c0 00 00 00 00 ee 9d 98 00 00 00 00 80 00 02 00 ................
> backtrace:
> [<c000000000078874>] .alloc_resource+0xb8/0xe0
> [<c000000000079b50>] .__request_region+0x70/0x1c4
> [<c00000000007a010>] .__devm_request_region+0x8c/0x138
> [<c0000000006e0dc8>] .fman_port_probe+0x170/0x420
> [<c0000000005cecb8>] .platform_drv_probe+0x84/0x108
> [<c0000000005cc620>] .driver_probe_device+0x2c4/0x394
> [<c0000000005cc814>] .__driver_attach+0x124/0x128
> [<c0000000005c9ad4>] .bus_for_each_dev+0xb4/0x110
> [<c0000000005cca1c>] .driver_attach+0x34/0x4c
> [<c0000000005ca9b0>] .bus_add_driver+0x264/0x2a4
> [<c0000000005cd9e0>] .driver_register+0x94/0x160
> [<c0000000005cfea4>] .__platform_driver_register+0x60/0x7c
> [<c000000000f86a00>] .fman_port_load+0x28/0x64
> [<c000000000f4106c>] .do_one_initcall+0xd4/0x1a8
> [<c000000000f412fc>] .kernel_init_freeable+0x1bc/0x2a4
> [<c00000000000180c>] .kernel_init+0x24/0x138
>
> Indeed, the new resource (created in __request_region) will be linked
> to the given resource living on the stack, which will end its lifetime
> after the function calling __devm_request_region has finished.
> Meaning the new resource allocated is no longer reachable.
>
> Now that the main fman driver is no longer reserving the region
> used by fman-port, this previous hack is no longer needed
> and we can use the regular call to devm_request_mem_region instead,
> solving those bugs at the same time.
>
> Signed-off-by: Patrick Havelange <[email protected]>
> ---
> drivers/net/ethernet/freescale/fman/fman_port.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/fman/fman_port.c
> b/drivers/net/ethernet/freescale/fman/fman_port.c
> index d9baac0dbc7d..354974939d9d 100644
> --- a/drivers/net/ethernet/freescale/fman/fman_port.c
> +++ b/drivers/net/ethernet/freescale/fman/fman_port.c
> @@ -1878,10 +1878,10 @@ static int fman_port_probe(struct platform_device
> *of_dev)
>
> of_node_put(port_node);
>
> - dev_res = __devm_request_region(port->dev, &res, res.start,
> - resource_size(&res), "fman-port");
> + dev_res = devm_request_mem_region(port->dev, res.start,
> + resource_size(&res), "fman-port");
> if (!dev_res) {
> - dev_err(port->dev, "%s: __devm_request_region() failed\n",
> + dev_err(port->dev, "%s: devm_request_mem_region() failed\n",
> __func__);
> err = -EINVAL;
> goto free_port;
> --
> 2.17.1
Hi Patrick,
please send a fix for the issue, targeting the net tree, separate from the
other change you are trying to introduce. We need a better explanation for
the latter and it should go through the net-next tree, if accepted.
Madalin
On 2020-12-03 09:44, Madalin Bucur wrote:
>> -----Original Message-----
>> From: Patrick Havelange <[email protected]>
>> Sent: 02 December 2020 18:16
>> To: Madalin Bucur <[email protected]>; David S. Miller
>> <[email protected]>; Jakub Kicinski <[email protected]>;
>> [email protected]; [email protected]
>> Cc: Patrick Havelange <[email protected]>
>> Subject: [PATCH 2/4] net: freescale/fman-port: remove direct use of
>> __devm_request_region
>>
>> This driver was directly calling __devm_request_region with a specific
>> resource on the stack as parameter. This is invalid as
>> __devm_request_region expects the given resource passed as parameter
>> to live longer than the call itself, as the pointer to the resource
>> will be stored inside the internal struct used by the devres
>> management.
>>
>> In addition to this issue, a related bug has been found by kmemleak
>> with this trace :
>> unreferenced object 0xc0000001efc01880 (size 64):
>> comm "swapper/0", pid 1, jiffies 4294669078 (age 3620.536s)
>> hex dump (first 32 bytes):
>> 00 00 00 0f fe 4a c0 00 00 00 00 0f fe 4a cf ff .....J.......J..
>> c0 00 00 00 00 ee 9d 98 00 00 00 00 80 00 02 00 ................
>> backtrace:
>> [<c000000000078874>] .alloc_resource+0xb8/0xe0
>> [<c000000000079b50>] .__request_region+0x70/0x1c4
>> [<c00000000007a010>] .__devm_request_region+0x8c/0x138
>> [<c0000000006e0dc8>] .fman_port_probe+0x170/0x420
>> [<c0000000005cecb8>] .platform_drv_probe+0x84/0x108
>> [<c0000000005cc620>] .driver_probe_device+0x2c4/0x394
>> [<c0000000005cc814>] .__driver_attach+0x124/0x128
>> [<c0000000005c9ad4>] .bus_for_each_dev+0xb4/0x110
>> [<c0000000005cca1c>] .driver_attach+0x34/0x4c
>> [<c0000000005ca9b0>] .bus_add_driver+0x264/0x2a4
>> [<c0000000005cd9e0>] .driver_register+0x94/0x160
>> [<c0000000005cfea4>] .__platform_driver_register+0x60/0x7c
>> [<c000000000f86a00>] .fman_port_load+0x28/0x64
>> [<c000000000f4106c>] .do_one_initcall+0xd4/0x1a8
>> [<c000000000f412fc>] .kernel_init_freeable+0x1bc/0x2a4
>> [<c00000000000180c>] .kernel_init+0x24/0x138
>>
>> Indeed, the new resource (created in __request_region) will be linked
>> to the given resource living on the stack, which will end its lifetime
>> after the function calling __devm_request_region has finished.
>> Meaning the new resource allocated is no longer reachable.
>>
>> Now that the main fman driver is no longer reserving the region
>> used by fman-port, this previous hack is no longer needed
>> and we can use the regular call to devm_request_mem_region instead,
>> solving those bugs at the same time.
>>
>> Signed-off-by: Patrick Havelange <[email protected]>
>> ---
>> drivers/net/ethernet/freescale/fman/fman_port.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/fman/fman_port.c
>> b/drivers/net/ethernet/freescale/fman/fman_port.c
>> index d9baac0dbc7d..354974939d9d 100644
>> --- a/drivers/net/ethernet/freescale/fman/fman_port.c
>> +++ b/drivers/net/ethernet/freescale/fman/fman_port.c
>> @@ -1878,10 +1878,10 @@ static int fman_port_probe(struct platform_device
>> *of_dev)
>>
>> of_node_put(port_node);
>>
>> - dev_res = __devm_request_region(port->dev, &res, res.start,
>> - resource_size(&res), "fman-port");
>> + dev_res = devm_request_mem_region(port->dev, res.start,
>> + resource_size(&res), "fman-port");
>> if (!dev_res) {
>> - dev_err(port->dev, "%s: __devm_request_region() failed\n",
>> + dev_err(port->dev, "%s: devm_request_mem_region() failed\n",
>> __func__);
>> err = -EINVAL;
>> goto free_port;
>> --
>> 2.17.1
>
> Hi Patrick,
>
> please send a fix for the issue, targeting the net tree, separate from the
> other change you are trying to introduce. We need a better explanation for
> the latter and it should go through the net-next tree, if accepted.
Hello,
I've resent the series with a cover letter having a bit more
explanations. I think all the patches should be applied on net, as they
are linked to the same issue/resolution, and are not independent.
BR,
Patrick H.