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| author | Hugh Dickins <hughd@google.com> | 2011-03-14 01:08:47 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-03-14 08:29:50 -0700 |
| commit | 2fbfac4e053861925fa3fffcdc327649b09af54c (patch) | |
| tree | 36d9da87f5a42d61cd8be2fd02bab666cb8ac145 /mm | |
| parent | c44ed965be7a84afaa07543c04eb97a5dfe93422 (diff) | |
| download | lwn-2fbfac4e053861925fa3fffcdc327649b09af54c.tar.gz lwn-2fbfac4e053861925fa3fffcdc327649b09af54c.zip | |
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>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/huge_memory.c | 6 |
1 files changed, 5 insertions, 1 deletions
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); |