3.19-stable review patch. If anyone has any objections, please let me know.
------------------ From: Christian Borntraeger <[email protected]> commit 1760f1eb7ec485197bd3a8a9c13e4160bb740275 upstream. ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the p2m code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger <[email protected]> Reviewed-by: Juergen Gross <[email protected]> Acked-by: David Vrabel <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- arch/x86/xen/p2m.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/xen/p2m.c +++ b/arch/x86/xen/p2m.c @@ -554,7 +554,7 @@ static bool alloc_p2m(unsigned long pfn) mid_mfn = NULL; } - p2m_pfn = pte_pfn(ACCESS_ONCE(*ptep)); + p2m_pfn = pte_pfn(READ_ONCE(*ptep)); if (p2m_pfn == PFN_DOWN(__pa(p2m_identity)) || p2m_pfn == PFN_DOWN(__pa(p2m_missing))) { /* p2m leaf page is missing */ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
