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.
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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