diff mbox

[PATCHv9-rebased2,03/37] mm, thp: fix locking inconsistency in collapse_huge_page

Message ID 1466021202-61880-4-git-send-email-kirill.shutemov@linux.intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Kirill A . Shutemov June 15, 2016, 8:06 p.m. UTC 
From: Ebru Akagunduz <ebru.akagunduz@gmail.com>

After creating revalidate vma function, locking inconsistency occured
due to directing the code path to wrong label. This patch directs
to correct label and fix the inconsistency.

Related commit that caused inconsistency:
http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=da4360877094368f6dfe75bbe804b0f0a5d575b0

Link: http://lkml.kernel.org/r/1464956884-4644-1-git-send-email-ebru.akagunduz@gmail.com
Signed-off-by: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/huge_memory.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

Comments

Sergey Senozhatsky June 16, 2016, 12:43 a.m. UTC | #1 
Hello,

On (06/15/16 23:06), Kirill A. Shutemov wrote:
[..]
> After creating revalidate vma function, locking inconsistency occured
> due to directing the code path to wrong label. This patch directs
> to correct label and fix the inconsistency.
> 
> Related commit that caused inconsistency:
> http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=da4360877094368f6dfe75bbe804b0f0a5d575b0


as far as I remember, Vlastimil had "one more thing" to ask
http://marc.info/?l=linux-mm&m=146521832732210&w=2

or is it safe?


	-ss
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Kirill A. Shutemov June 16, 2016, 8:02 a.m. UTC | #2 
On Thu, Jun 16, 2016 at 09:43:07AM +0900, Sergey Senozhatsky wrote:
> Hello,
> 
> On (06/15/16 23:06), Kirill A. Shutemov wrote:
> [..]
> > After creating revalidate vma function, locking inconsistency occured
> > due to directing the code path to wrong label. This patch directs
> > to correct label and fix the inconsistency.
> > 
> > Related commit that caused inconsistency:
> > http://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git/commit/?id=da4360877094368f6dfe75bbe804b0f0a5d575b0
> 
> 
> as far as I remember, Vlastimil had "one more thing" to ask
> http://marc.info/?l=linux-mm&m=146521832732210&w=2
> 
> or is it safe?

As I mentioned in cover letter, 05/37 address the issue.

I didn't fold it in. It's up to Andrew.
diff mbox

Patch

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 7bb30e853335..1777b806de96 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2487,13 +2487,18 @@  static void collapse_huge_page(struct mm_struct *mm,
 
 	down_read(&mm->mmap_sem);
 	result = hugepage_vma_revalidate(mm, address);
-	if (result)
-		goto out;
+	if (result) {
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		up_read(&mm->mmap_sem);
+		goto out_nolock;
+	}
 
 	pmd = mm_find_pmd(mm, address);
 	if (!pmd) {
 		result = SCAN_PMD_NULL;
-		goto out;
+		mem_cgroup_cancel_charge(new_page, memcg, true);
+		up_read(&mm->mmap_sem);
+		goto out_nolock;
 	}
 
 	/*
@@ -2502,8 +2507,9 @@  static void collapse_huge_page(struct mm_struct *mm,
 	 * label out. Continuing to collapse causes inconsistency.
 	 */
 	if (!__collapse_huge_page_swapin(mm, vma, address, pmd)) {
+		mem_cgroup_cancel_charge(new_page, memcg, true);
 		up_read(&mm->mmap_sem);
-		goto out;
+		goto out_nolock;
 	}
 
 	up_read(&mm->mmap_sem);