On Wed, Sep 26, 2018 at 08:48:58AM +0530, Aneesh Kumar K.V wrote: > We clear the pte temporarily during read/modify/write update of the pte. If we > take a page fault while the pte is cleared, the application can get SIGBUS. One > such case is with remap_pfn_range without a backing vm_ops->fault callback. > do_fault will return SIGBUS in that case. > > cpu 0 cpu1 > mprotect() > ptep_modify_prot_start()/pte cleared. > . > . page fault. > . > . > prep_modify_prot_commit() > > Fix this by taking page table lock and rechecking for pte_none. > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxx> > --- > V1: > * update commit message. You choosed to stick with VM_FAULT_NOPAGE, that's fine. Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Should it be in stable? -- Kirill A. Shutemov
