diff options
| author | Juergen Gross | 2015-01-12 06:05:08 +0100 |
|---|---|---|
| committer | David Vrabel | 2015-01-12 10:09:40 +0000 |
| commit | f241b0b891c903da2465b7a98eaf650784e666da (patch) | |
| tree | ff0134e6a0dd55e5066719de73dac85d8ea972fe | |
| parent | 82c92ed1357bca22a5d637fbb93dab3eb18a8e8c (diff) | |
xen: correct race in alloc_p2m_pmd()
When allocating a new pmd for the linear mapped p2m list a check is
done for not introducing another pmd when this just happened on
another cpu. In this case the old pte pointer was returned which
points to the p2m_missing or p2m_identity page. The correct value
would be the pointer to the found new page.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
| -rw-r--r-- | arch/x86/xen/p2m.c | 9 |
1 files changed, 3 insertions, 6 deletions
diff --git a/arch/x86/xen/p2m.c b/arch/x86/xen/p2m.c index ff4ebd820603..70fb5075c901 100644 --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -439,10 +439,9 @@ EXPORT_SYMBOL_GPL(get_phys_to_machine); * a new pmd is to replace p2m_missing_pte or p2m_identity_pte by a individual * pmd. In case of PAE/x86-32 there are multiple pmds to allocate! */ -static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *ptep, pte_t *pte_pg) +static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *pte_pg) { pte_t *ptechk; - pte_t *pteret = ptep; pte_t *pte_newpg[PMDS_PER_MID_PAGE]; pmd_t *pmdp; unsigned int level; @@ -476,8 +475,6 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *ptep, pte_t *pte_pg) if (ptechk == pte_pg) { set_pmd(pmdp, __pmd(__pa(pte_newpg[i]) | _KERNPG_TABLE)); - if (vaddr == (addr & ~(PMD_SIZE - 1))) - pteret = pte_offset_kernel(pmdp, addr); pte_newpg[i] = NULL; } @@ -491,7 +488,7 @@ static pte_t *alloc_p2m_pmd(unsigned long addr, pte_t *ptep, pte_t *pte_pg) vaddr += PMD_SIZE; } - return pteret; + return lookup_address(addr, &level); } /* @@ -520,7 +517,7 @@ static bool alloc_p2m(unsigned long pfn) if (pte_pg == p2m_missing_pte || pte_pg == p2m_identity_pte) { /* PMD level is missing, allocate a new one */ - ptep = alloc_p2m_pmd(addr, ptep, pte_pg); + ptep = alloc_p2m_pmd(addr, pte_pg); if (!ptep) return false; } |