From 2fbfac4e053861925fa3fffcdc327649b09af54c Mon Sep 17 00:00:00 2001
From: Hugh Dickins <hughd@google.com>
Date: Mon, 14 Mar 2011 01:08:47 -0700
Subject: [PATCH] thp+memcg-numa: fix BUG at include/linux/mm.h:370!
THP's collapse_huge_page() has an understandable but ugly difference
in when its huge page is allocated: inside if NUMA but outside if not.
It's hardly surprising that the memcg failure path forgot that, freeing
the page in the non-NUMA case, then hitting a VM_BUG_ON in get_page()
(or even worse, using the freed page).
Signed-off-by: Hugh Dickins <hughd@google.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
mm/huge_memory.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index dbe99a5f2073..113e35c47502 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1762,6 +1762,10 @@ static void collapse_huge_page(struct mm_struct *mm,
#ifndef CONFIG_NUMA
VM_BUG_ON(!*hpage);
new_page = *hpage;
+ if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
+ up_read(&mm->mmap_sem);
+ return;
+ }
#else
VM_BUG_ON(*hpage);
/*
@@ -1781,12 +1785,12 @@ static void collapse_huge_page(struct mm_struct *mm,
*hpage = ERR_PTR(-ENOMEM);
return;
}
-#endif
if (unlikely(mem_cgroup_newpage_charge(new_page, mm, GFP_KERNEL))) {
up_read(&mm->mmap_sem);
put_page(new_page);
return;
}
+#endif
/* after allocating the hugepage upgrade to mmap_sem write mode */
up_read(&mm->mmap_sem);
--
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