This is a note to let you know that I've just added the patch titled
usb: cdns3: imx: fix can't create core device the second time issue
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 2ef02b846ee2526249a562a66d6dcb25fcbca9d8 Mon Sep 17 00:00:00 2001
From: Peter Chen <peter.chen(a)nxp.com>
Date: Thu, 10 Dec 2020 21:31:37 +0800
Subject: usb: cdns3: imx: fix can't create core device the second time issue
The cdns3 core device is populated by calling of_platform_populate,
the flag OF_POPULATED is set for core device node, if this flag
is not cleared, when calling of_platform_populate the second time
after loading parent module again, the OF code will not try to create
platform device for core device.
To fix it, it uses of_platform_depopulate to depopulate the core
device which the parent created, and the flag OF_POPULATED for
core device node will be cleared accordingly.
Cc: <stable(a)vger.kernel.org>
Fixes: 1e056efab993 ("usb: cdns3: add NXP imx8qm glue layer")
Signed-off-by: Peter Chen <peter.chen(a)nxp.com>
---
drivers/usb/cdns3/cdns3-imx.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
diff --git a/drivers/usb/cdns3/cdns3-imx.c b/drivers/usb/cdns3/cdns3-imx.c
index 4d3fedc86753..6b358e8be579 100644
--- a/drivers/usb/cdns3/cdns3-imx.c
+++ b/drivers/usb/cdns3/cdns3-imx.c
@@ -218,20 +218,11 @@ static int cdns_imx_probe(struct platform_device *pdev)
return ret;
}
-static int cdns_imx_remove_core(struct device *dev, void *data)
-{
- struct platform_device *pdev = to_platform_device(dev);
-
- platform_device_unregister(pdev);
-
- return 0;
-}
-
static int cdns_imx_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
- device_for_each_child(dev, NULL, cdns_imx_remove_core);
+ of_platform_depopulate(dev);
platform_set_drvdata(pdev, NULL);
return 0;
--
2.30.0
There is a race condition between __free_huge_page()
and dissolve_free_huge_page().
CPU0: CPU1:
// page_count(page) == 1
put_page(page)
__free_huge_page(page)
dissolve_free_huge_page(page)
spin_lock(&hugetlb_lock)
// PageHuge(page) && !page_count(page)
update_and_free_page(page)
// page is freed to the buddy
spin_unlock(&hugetlb_lock)
spin_lock(&hugetlb_lock)
clear_page_huge_active(page)
enqueue_huge_page(page)
// It is wrong, the page is already freed
spin_unlock(&hugetlb_lock)
The race windows is between put_page() and dissolve_free_huge_page().
We should make sure that the page is already on the free list
when it is dissolved.
Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Muchun Song <songmuchun(a)bytedance.com>
Cc: stable(a)vger.kernel.org
---
mm/hugetlb.c | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 4741d60f8955..4a9011e12175 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -79,6 +79,21 @@ DEFINE_SPINLOCK(hugetlb_lock);
static int num_fault_mutexes;
struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp;
+static inline bool PageHugeFreed(struct page *head)
+{
+ return page_private(head + 4) == -1UL;
+}
+
+static inline void SetPageHugeFreed(struct page *head)
+{
+ set_page_private(head + 4, -1UL);
+}
+
+static inline void ClearPageHugeFreed(struct page *head)
+{
+ set_page_private(head + 4, 0);
+}
+
/* Forward declaration */
static int hugetlb_acct_memory(struct hstate *h, long delta);
@@ -1028,6 +1043,7 @@ static void enqueue_huge_page(struct hstate *h, struct page *page)
list_move(&page->lru, &h->hugepage_freelists[nid]);
h->free_huge_pages++;
h->free_huge_pages_node[nid]++;
+ SetPageHugeFreed(page);
}
static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
@@ -1044,6 +1060,7 @@ static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid)
list_move(&page->lru, &h->hugepage_activelist);
set_page_refcounted(page);
+ ClearPageHugeFreed(page);
h->free_huge_pages--;
h->free_huge_pages_node[nid]--;
return page;
@@ -1504,6 +1521,7 @@ static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
spin_lock(&hugetlb_lock);
h->nr_huge_pages++;
h->nr_huge_pages_node[nid]++;
+ ClearPageHugeFreed(page);
spin_unlock(&hugetlb_lock);
}
@@ -1770,6 +1788,14 @@ int dissolve_free_huge_page(struct page *page)
int nid = page_to_nid(head);
if (h->free_huge_pages - h->resv_huge_pages == 0)
goto out;
+
+ /*
+ * We should make sure that the page is already on the free list
+ * when it is dissolved.
+ */
+ if (unlikely(!PageHugeFreed(head)))
+ goto out;
+
/*
* Move PageHWPoison flag from head page to the raw error page,
* which makes any subpages rather than the error page reusable.
--
2.11.0