At 11/06/2012 10:05 PM, Dan Carpenter Wrote:
> On Tue, Nov 06, 2012 at 10:10:11AM +0800, Wen Congyang wrote:
>> At 11/06/2012 02:11 AM, Dan Carpenter Wrote:
>>> Hello Wen Congyang,
>>>
>>> The patch 306859f13dc1: "acpi_memhotplug.c: don't allow to eject the
>>> memory device if it is being used" from Nov 3, 2012, leads to the
>>> following Smatch warning:
>>> drivers/acpi/acpi_memhotplug.c:367 acpi_memory_remove_memory()
>>> warn: inconsistent returns mutex:&mem_device->list_lock:
>>> locked (357,361) unlocked (367)
>>
>> Thanks for pointing it out.
>>
>> The patch 306859f13dc1 is in akpm's tree, and it conflicts with another
>> patch in linux-pm's tree. So Andrew Morton drops them.
>>
>> I will resend them based on linux-pm's next tree.
>
> Ok. Today's linux-next version 85fcb3758c10e "ACPI / memory-hotplug:
> introduce a mutex lock to protect the list in acpi_memory_device"
> has a similar problem and should be fixed as well.
>
> 319 static int acpi_memory_remove_memory(struct acpi_memory_device *mem_device)
> 320 {
> 321 int result;
> 322 struct acpi_memory_info *info, *n;
> 323
> 324 mutex_lock(&mem_device->list_lock);
> 325 list_for_each_entry_safe(info, n, &mem_device->res_list, list) {
> 326 if (info->enabled) {
> 327 result = remove_memory(info->start_addr, info->length);
> 328 if (result)
> 329 return result;
> ^^^^^^^^^^^^^
> We are still holding the lock here.
Yes, I found this problem.
Thanks
Wen Congyang
>
> 330 }
> 331
> 332 list_del(&info->list);
> 333 kfree(info);
> 334 }
> 335 mutex_unlock(&mem_device->list_lock);
> 336
> 337 return 0;
> 338 }
>
> regards,
> dan carpenter
>
>
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