From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 10 Apr 2019 20:44:01 -0400 From: Steven Rostedt Subject: Re: [PATCH v3 3/3] module: Make __tracepoints_ptrs as read-only Message-ID: <20190410204401.62f928ca@gandalf.local.home> In-Reply-To: <20190410202902.GA167446@google.com> References: <20190410195708.162185-1-joel@joelfernandes.org> <20190410195708.162185-3-joel@joelfernandes.org> <20190410161112.540017d9@gandalf.local.home> <20190410202902.GA167446@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit To: Joel Fernandes Cc: linux-kernel@vger.kernel.org, paulmck@linux.vnet.ibm.com, keescook@chromium.org, mathieu.desnoyers@efficios.com, Jessica Yu , kernel-hardening@lists.openwall.com, kernel-team@android.com, rcu@vger.kernel.org List-ID: On Wed, 10 Apr 2019 16:29:02 -0400 Joel Fernandes wrote: > The srcu structure pointer array is modified at module load time because the > array is fixed up by the module loader at load-time with the final locations > of the tracepoints right? Basically relocation fixups. At compile time, I > believe it is not know what the values in the ptr array are. I believe same > is true for the tracepoint ptrs array. > > Also it needs to be in a separate __tracepoint_ptrs so that this code works: > > > #ifdef CONFIG_TRACEPOINTS > mod->tracepoints_ptrs = section_objs(info, "__tracepoints_ptrs", > sizeof(*mod->tracepoints_ptrs), > &mod->num_tracepoints); > #endif > > Did I miss some point? Thanks, But there's a lot of others too. Hmm, does this mean that the RO data sections that are in modules are not set to RO? There's a bunch of separate sections that are RO. Just look in include/asm-generic/vmlinux.lds.h under the RO_DATA_SECTION() macro. A lot of the sections saved in module.c:find_module_sections() are in that RO_DATA when compiled as a builtin. Are they not RO when loaded via a module? If this is the case, there probably is going to be a lot more sections added to your list. -- Steve