On Fri, Feb 28, 2014 at 02:32:02PM +0530, Aneesh Kumar K.V wrote: > From: Liu Ping Fan <pingf...@linux.vnet.ibm.com> > > When doing some numa tests on powerpc, I triggered an oops bug. I find > it is caused by using page->_last_cpupid. It should be initialized as > "-1 & LAST_CPUPID_MASK", but not "-1". Otherwise, in task_numa_fault(), > we will miss the checking (last_cpupid == (-1 & LAST_CPUPID_MASK)). > And finally cause an oops bug in task_numa_group(), since the online cpu is > less than possible cpu. This happen with CONFIG_SPARSE_VMEMMAP disabled > > Signed-off-by: Liu Ping Fan <pingf...@linux.vnet.ibm.com> > Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <pet...@infradead.org> > --- > > include/linux/mm.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/mm.h b/include/linux/mm.h > index f28f46eade6a..86245839c9fa 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -757,7 +757,7 @@ static inline bool __cpupid_match_pid(pid_t task_pid, int > cpupid) > #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS > static inline int page_cpupid_xchg_last(struct page *page, int cpupid) > { > - return xchg(&page->_last_cpupid, cpupid); > + return xchg(&page->_last_cpupid, cpupid & LAST_CPUPID_MASK); > } > > static inline int page_cpupid_last(struct page *page) > @@ -766,7 +766,7 @@ static inline int page_cpupid_last(struct page *page) > } > static inline void page_cpupid_reset_last(struct page *page) > { > - page->_last_cpupid = -1; > + page->_last_cpupid = -1 & LAST_CPUPID_MASK; > } > #else > static inline int page_cpupid_last(struct page *page) > -- > 1.8.3.2 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/