On Sun, Jan 26, 2020 at 05:47:57PM +0300, Dmitry Osipenko wrote:

18.01.2020 02:22, Wei Yang пишет:

quoted

Use the general helper instead of do it by hand.

Signed-off-by: Wei Yang <redacted>
---
 mm/mremap.c | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/mm/mremap.c b/mm/mremap.c
index c2af8ba4ba43..a258914f3ee1 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c

@@ -253,11 +253,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 
 	for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
 		cond_resched();
-		next = (old_addr + PMD_SIZE) & PMD_MASK;
-		/* even if next overflowed, extent below will be ok */
+		next = pmd_addr_end(old_addr, old_end);
 		extent = next - old_addr;
-		if (extent > old_end - old_addr)
-			extent = old_end - old_addr;
 		old_pmd = get_old_pmd(vma->vm_mm, old_addr);
 		if (!old_pmd)
 			continue;

@@ -301,7 +298,7 @@ unsigned long move_page_tables(struct vm_area_struct *vma,
 
 		if (pte_alloc(new_vma->vm_mm, new_pmd))
 			break;
-		next = (new_addr + PMD_SIZE) & PMD_MASK;
+		next = pmd_addr_end(new_addr, new_addr + len);
 		if (extent > next - new_addr)
 			extent = next - new_addr;
 		move_ptes(vma, old_pmd, old_addr, old_addr + extent, new_vma,

Hello Wei,

Starting with next-20200122, I'm seeing the following in KMSG on NVIDIA
Tegra (ARM32):

 BUG: Bad rss-counter state mm:(ptrval) type:MM_ANONPAGES val:190

Thanks.

Would you mind letting me know which case you are testing? Or the special
thing is 32-bit platform?

and eventually kernel hangs.

Git's bisection points to this patch and reverting it helps. Please fix,
thanks in advance.

-- 
Wei Yang
Help you, Help me

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