Messages in this thread Patch in this message | | | Subject | Re: [PATCH] arm/mach-at91/pm: Do not double put the device node | From | Claudiu Beznea <> | Date | Thu, 16 Aug 2018 12:32:57 +0300 |
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Hi Alexandre,
On 14.08.2018 15:59, Alexandre Belloni wrote: > On 14/08/2018 09:54:56+0800, zhong jiang wrote: >> Device node iterators put the previous value of the index variable, >> so an explicit put causes a double put. >> > > While for_each_matching_node_and_match will get and put the node > properly, there is also a call to of_find_device_by_node that will get a > reference to the node. >
Looking through of_find_device_by_node() it seems that a put_device() on the struct device member of the returned struct platform_device has to be called instead of of_node_put().
of_find_device_by_node() calls bus_find_device():
dev = bus_find_device(&platform_bus_type, NULL, np, of_dev_node_match);
the match function, of_dev_node_match(), is just as follows:
static int of_dev_node_match(struct device *dev, void *data) { return dev->of_node == data; }
but bus_find_device() takes a reference to the struct device returned in case it founds a match, via get_device():
struct device *bus_find_device(struct bus_type *bus, struct device *start, void *data, int (*match)(struct device *dev, void*data)) { struct klist_iter i; struct device *dev; if (!bus || !bus->p) return NULL; klist_iter_init_node(&bus->p->klist_devices, &i, (start ? &start->p->knode_bus : NULL)); while ((dev = next_device(&i))) if (match(dev, data) && get_device(dev)) break; klist_iter_exit(&i); return dev; }
So, I think a put_device(&pdev->dev) has to be called in at91_pm_config_ws() instead of of_node_put(np). My bad!
Thank you, Claudiu Beznea
>> I detect the issue with the help of Coccinelle. >> >> Signed-off-by: zhong jiang <zhongjiang@huawei.com> >> --- >> arch/arm/mach-at91/pm.c | 5 +---- >> 1 file changed, 1 insertion(+), 4 deletions(-) >> >> diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c >> index 32fae4d..a5ec35f 100644 >> --- a/arch/arm/mach-at91/pm.c >> +++ b/arch/arm/mach-at91/pm.c >> @@ -143,15 +143,12 @@ static int at91_pm_config_ws(unsigned int pm_mode, bool set) >> >> /* Check if enabled on SHDWC. */ >> if (wsi->shdwc_mr_bit && !(val & wsi->shdwc_mr_bit)) >> - goto put_node; >> + continue; >> >> mode |= wsi->pmc_fsmr_bit; >> if (wsi->set_polarity) >> polarity |= wsi->pmc_fsmr_bit; >> } >> - >> -put_node: >> - of_node_put(np); >> } >> >> if (mode) { >> -- >> 1.7.12.4 >> >
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