On Mon, Oct 19, 2015 at 03:54:29PM -0700, Andi Kleen wrote: > @@ -2307,7 +2312,13 @@ perf_callchain_user(struct perf_callchain_entry > *entry, struct pt_regs *regs) > frame.next_frame = NULL; > frame.return_address = 0; > > - bytes = copy_from_user_nmi(&frame, fp, sizeof(frame)); > + if (!access_ok(VERIFY_READ, fp, 16)) > + break; > + > + bytes = __copy_from_user_nmi(&frame.next_frame, fp, 8); > + if (bytes != 0) > + break; > + bytes = __copy_from_user_nmi(&frame.return_address, fp+8, 8); > if (bytes != 0) > break; >
The previous patch that introduces this function states that any caller must have pagefault_disable() or be from interrupt context. Perf can call this function from !interrupt context (imagine a tracepoint or other software event), should we therefore not add a pagefault_disable()/enable() pair around the entire while() loop? -- 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/
