4.9-stable review patch. If anyone has any objections, please let me know.
------------------ From: Laurent Dufour <lduf...@linux.vnet.ibm.com> commit de0c799bba2610a8e1e9a50d76a28614520a4cd4 upstream. Seen while reading the code, in handle_mm_fault(), in the case arch_vma_access_permitted() is failing the call to mem_cgroup_oom_disable() is not made. To fix that, move the call to mem_cgroup_oom_enable() after calling arch_vma_access_permitted() as it should not have entered the memcg OOM. Link: http://lkml.kernel.org/r/1504625439-31313-1-git-send-email-lduf...@linux.vnet.ibm.com Fixes: bae473a423f6 ("mm: introduce fault_env") Signed-off-by: Laurent Dufour <lduf...@linux.vnet.ibm.com> Acked-by: Kirill A. Shutemov <kir...@shutemov.name> Acked-by: Michal Hocko <mho...@suse.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- mm/memory.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) --- a/mm/memory.c +++ b/mm/memory.c @@ -3596,6 +3596,11 @@ int handle_mm_fault(struct vm_area_struc /* do counter updates before entering really critical section. */ check_sync_rss_stat(current); + if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, + flags & FAULT_FLAG_INSTRUCTION, + flags & FAULT_FLAG_REMOTE)) + return VM_FAULT_SIGSEGV; + /* * Enable the memcg OOM handling for faults triggered in user * space. Kernel faults are handled more gracefully. @@ -3603,11 +3608,6 @@ int handle_mm_fault(struct vm_area_struc if (flags & FAULT_FLAG_USER) mem_cgroup_oom_enable(); - if (!arch_vma_access_permitted(vma, flags & FAULT_FLAG_WRITE, - flags & FAULT_FLAG_INSTRUCTION, - flags & FAULT_FLAG_REMOTE)) - return VM_FAULT_SIGSEGV; - if (unlikely(is_vm_hugetlb_page(vma))) ret = hugetlb_fault(vma->vm_mm, vma, address, flags); else
