2023-10-16 23:25:39

by Ira Weiny

Subject: [PATCH] cxl/pmu: Ensure put_device on pmu devices

The following kmemleaks were detected when removing the cxl module
stack:

unreferenced object 0xffff88822616b800 (size 1024):
...
backtrace:
[<00000000bedc6f83>] kmalloc_trace+0x26/0x90
[<00000000448d1afc>] devm_cxl_pmu_add+0x3a/0x110 [cxl_core]
[<00000000ca3bfe16>] 0xffffffffa105213b
[<00000000ba7f78dc>] local_pci_probe+0x41/0x90
[<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
...
unreferenced object 0xffff8882260abcc0 (size 16):
...
hex dump (first 16 bytes):
70 6d 75 5f 6d 65 6d 30 2e 30 00 26 82 88 ff ff pmu_mem0.0.&....
backtrace:
...
[<00000000152b5e98>] dev_set_name+0x43/0x50
[<00000000c228798b>] devm_cxl_pmu_add+0x102/0x110 [cxl_core]
[<00000000ca3bfe16>] 0xffffffffa105213b
[<00000000ba7f78dc>] local_pci_probe+0x41/0x90
[<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
...
unreferenced object 0xffff8882272af200 (size 256):
...
backtrace:
[<00000000bedc6f83>] kmalloc_trace+0x26/0x90
[<00000000a14d1813>] device_add+0x4ea/0x890
[<00000000a3f07b47>] devm_cxl_pmu_add+0xbe/0x110 [cxl_core]
[<00000000ca3bfe16>] 0xffffffffa105213b
[<00000000ba7f78dc>] local_pci_probe+0x41/0x90
[<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
...

devm_cxl_pmu_add() correctly registers a device remove function but it
only calls device_del() which is only part of device unregistration.

Properly call device_unregister() to free up the memory associated with
the device.

Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")
Cc: Jonathan Cameron <[email protected]>
Signed-off-by: Ira Weiny <[email protected]>
---
drivers/cxl/core/pmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cxl/core/pmu.c b/drivers/cxl/core/pmu.c
index 7684c843e5a5..5d8e06b0ba6e 100644
--- a/drivers/cxl/core/pmu.c
+++ b/drivers/cxl/core/pmu.c
@@ -23,7 +23,7 @@ const struct device_type cxl_pmu_type = {

static void remove_dev(void *dev)
{
- device_del(dev);
+ device_unregister(dev);
}

int devm_cxl_pmu_add(struct device *parent, struct cxl_pmu_regs *regs,

---
base-commit: 58720809f52779dc0f08e53e54b014209d13eebb
change-id: 20231016-pmu-unregister-fix-345480926a58

Best regards,
--
Ira Weiny <[email protected]>

2023-10-16 23:43:56

by Dave Jiang

Subject: Re: [PATCH] cxl/pmu: Ensure put_device on pmu devices

On 10/16/23 16:25, Ira Weiny wrote:
> The following kmemleaks were detected when removing the cxl module
> stack:
>
> unreferenced object 0xffff88822616b800 (size 1024):
> ...
> backtrace:
> [<00000000bedc6f83>] kmalloc_trace+0x26/0x90
> [<00000000448d1afc>] devm_cxl_pmu_add+0x3a/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
> unreferenced object 0xffff8882260abcc0 (size 16):
> ...
> hex dump (first 16 bytes):
> 70 6d 75 5f 6d 65 6d 30 2e 30 00 26 82 88 ff ff pmu_mem0.0.&....
> backtrace:
> ...
> [<00000000152b5e98>] dev_set_name+0x43/0x50
> [<00000000c228798b>] devm_cxl_pmu_add+0x102/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
> unreferenced object 0xffff8882272af200 (size 256):
> ...
> backtrace:
> [<00000000bedc6f83>] kmalloc_trace+0x26/0x90
> [<00000000a14d1813>] device_add+0x4ea/0x890
> [<00000000a3f07b47>] devm_cxl_pmu_add+0xbe/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
>
> devm_cxl_pmu_add() correctly registers a device remove function but it
> only calls device_del() which is only part of device unregistration.
>
> Properly call device_unregister() to free up the memory associated with
> the device.
>
> Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")
> Cc: Jonathan Cameron <[email protected]>
> Signed-off-by: Ira Weiny <[email protected]>

Reviewed-by: Dave Jiang <[email protected]>

Although I wonder if we can just give device_unregister() to devm_add_action_or_reset() directly.

> ---
> drivers/cxl/core/pmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/core/pmu.c b/drivers/cxl/core/pmu.c
> index 7684c843e5a5..5d8e06b0ba6e 100644
> --- a/drivers/cxl/core/pmu.c
> +++ b/drivers/cxl/core/pmu.c
> @@ -23,7 +23,7 @@ const struct device_type cxl_pmu_type = {
>
> static void remove_dev(void *dev)
> {
> - device_del(dev);
> + device_unregister(dev);
> }
>
> int devm_cxl_pmu_add(struct device *parent, struct cxl_pmu_regs *regs,
>
> ---
> base-commit: 58720809f52779dc0f08e53e54b014209d13eebb
> change-id: 20231016-pmu-unregister-fix-345480926a58
>
> Best regards,

2023-10-17 15:35:48

by Ira Weiny

Subject: Re: [PATCH] cxl/pmu: Ensure put_device on pmu devices

Dave Jiang wrote:
>
>

[snip]

> >
> > Properly call device_unregister() to free up the memory associated with
> > the device.
> >
> > Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")
> > Cc: Jonathan Cameron <[email protected]>
> > Signed-off-by: Ira Weiny <[email protected]>
>
> Reviewed-by: Dave Jiang <[email protected]>
>
> Although I wonder if we can just give device_unregister() to devm_add_action_or_reset() directly.
>

No because the action callback takes void * and device_unregister() takes
a struct device *.

Ira

[snip]

2023-10-17 16:22:34

by Dave Jiang

Subject: Re: [PATCH] cxl/pmu: Ensure put_device on pmu devices

On 10/17/23 08:35, Ira Weiny wrote:
> Dave Jiang wrote:
>>
>>
>
> [snip]
>
>>>
>>> Properly call device_unregister() to free up the memory associated with
>>> the device.
>>>
>>> Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")
>>> Cc: Jonathan Cameron <[email protected]>
>>> Signed-off-by: Ira Weiny <[email protected]>
>>
>> Reviewed-by: Dave Jiang <[email protected]>
>>
>> Although I wonder if we can just give device_unregister() to devm_add_action_or_reset() directly.
>>
>
> No because the action callback takes void * and device_unregister() takes
> a struct device *.

Ah right! I knew there was a reason for the wrapper....
>
> Ira
>
> [snip]

2023-10-18 10:51:02

by Jonathan Cameron

Subject: Re: [PATCH] cxl/pmu: Ensure put_device on pmu devices

On Mon, 16 Oct 2023 16:25:05 -0700
Ira Weiny <[email protected]> wrote:

> The following kmemleaks were detected when removing the cxl module
> stack:
>
> unreferenced object 0xffff88822616b800 (size 1024):
> ...
> backtrace:
> [<00000000bedc6f83>] kmalloc_trace+0x26/0x90
> [<00000000448d1afc>] devm_cxl_pmu_add+0x3a/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
> unreferenced object 0xffff8882260abcc0 (size 16):
> ...
> hex dump (first 16 bytes):
> 70 6d 75 5f 6d 65 6d 30 2e 30 00 26 82 88 ff ff pmu_mem0.0.&....
> backtrace:
> ...
> [<00000000152b5e98>] dev_set_name+0x43/0x50
> [<00000000c228798b>] devm_cxl_pmu_add+0x102/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
> unreferenced object 0xffff8882272af200 (size 256):
> ...
> backtrace:
> [<00000000bedc6f83>] kmalloc_trace+0x26/0x90
> [<00000000a14d1813>] device_add+0x4ea/0x890
> [<00000000a3f07b47>] devm_cxl_pmu_add+0xbe/0x110 [cxl_core]
> [<00000000ca3bfe16>] 0xffffffffa105213b
> [<00000000ba7f78dc>] local_pci_probe+0x41/0x90
> [<000000005bb027ac>] pci_device_probe+0xb0/0x1c0
> ...
>
> devm_cxl_pmu_add() correctly registers a device remove function but it
> only calls device_del() which is only part of device unregistration.
>
> Properly call device_unregister() to free up the memory associated with
> the device.
>
> Fixes: 1ad3f701c399 ("cxl/pci: Find and register CXL PMU devices")
> Cc: Jonathan Cameron <[email protected]>
> Signed-off-by: Ira Weiny <[email protected]>
Oops.

Reviewed-by: Jonathan Cameron <[email protected]>

> ---
> drivers/cxl/core/pmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/cxl/core/pmu.c b/drivers/cxl/core/pmu.c
> index 7684c843e5a5..5d8e06b0ba6e 100644
> --- a/drivers/cxl/core/pmu.c
> +++ b/drivers/cxl/core/pmu.c
> @@ -23,7 +23,7 @@ const struct device_type cxl_pmu_type = {
>
> static void remove_dev(void *dev)
> {
> - device_del(dev);
> + device_unregister(dev);
> }
>
> int devm_cxl_pmu_add(struct device *parent, struct cxl_pmu_regs *regs,
>
> ---
> base-commit: 58720809f52779dc0f08e53e54b014209d13eebb
> change-id: 20231016-pmu-unregister-fix-345480926a58
>
> Best regards,