On Tue, Apr 04, 2017 at 10:47:27AM -0700, Thomas Garnier wrote: > diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S > index 43512d4d7df2..6d598e7051c3 100644 > --- a/arch/arm64/kernel/entry.S > +++ b/arch/arm64/kernel/entry.S > @@ -744,6 +744,10 @@ ENDPROC(cpu_switch_to) > ret_fast_syscall: > disable_irq // disable interrupts > str x0, [sp, #S_X0] // returned x0 > + ldr x2, [tsk, #TSK_TI_ADDR_LIMIT] // check addr limit change > + mov x1, #TASK_SIZE_64 > + cmp x2, x1 > + b.ne addr_limit_fail KERNEL_DS is set to the maximum address (-1UL), so it would be easier to check against this here and avoid a "mov". Even simpler if you'd check against bit 63 of the address for KERNEL_DS: ldr x1, [tsk, TSK_TI_ADDR_LIMIT] // check addr limit change tbnz x1, #63, addr_limit_fail // KERNEL_DS is -1UL > ldr x1, [tsk, #TSK_TI_FLAGS] // re-check for syscall tracing > and x2, x1, #_TIF_SYSCALL_WORK > cbnz x2, ret_fast_syscall_trace > @@ -771,6 +775,11 @@ work_pending: > */ > ret_to_user: > disable_irq // disable interrupts > + ldr x2, [tsk, #TSK_TI_ADDR_LIMIT] // check addr limit change > + mov x1, #TASK_SIZE_64 > + cmp x2, x1 > + b.ne addr_limit_fail Same here. > + > ldr x1, [tsk, #TSK_TI_FLAGS] > and x2, x1, #_TIF_WORK_MASK > cbnz x2, work_pending > @@ -779,6 +788,12 @@ finish_ret_to_user: > kernel_exit 0 > ENDPROC(ret_to_user) > > +addr_limit_fail: > + stp x0, lr, [sp,#-16]! > + bl asm_verify_pre_usermode_state > + ldp x0, lr, [sp],#16 > + ret lr Where is this supposed to return? What is the value of lr when branching to addr_limit_fail? -- Catalin -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
