Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752270AbbKSFli (ORCPT ); Thu, 19 Nov 2015 00:41:38 -0500 Received: from mail-wm0-f41.google.com ([74.125.82.41]:37330 "EHLO mail-wm0-f41.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750972AbbKSFlh (ORCPT ); Thu, 19 Nov 2015 00:41:37 -0500 MIME-Version: 1.0 In-Reply-To: References: Date: Wed, 18 Nov 2015 22:41:36 -0700 Message-ID: Subject: Re: Linux 4.3 kallsyms_lookup_name not returning per_cpu symbol values From: Jeffrey Merkey To: linux-kernel Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2298 Lines: 71 Take that back, I just reproduced it again. Seems to affect random symbols not just per cpu. I'll research some more. On 11/18/15, Jeffrey Merkey wrote: > I tracked this down and it turns out to be a page mapping problem with > one of the sound drivers on the system trashing memory. It's a bug, > but a bug in a vendor supplied driver. > > Jeff > > On 11/18/15, Jeffrey Merkey wrote: >> kallsyms_lookup_name is not returning per_cpu symbols when called. >> The symbols show up when you run something with the kallsyms_iter >> struct but not through the regular interface. I have looked through >> the code and I am not able to determine with certainty if its designed >> this way or just busted. Any help with this would be appreciated. >> >> The following code does display the per_cpu symbols, they just don't >> seem to show up when called from kallsyms_lookup_name. >> >> >> struct kallsym_iter mdb_iter; >> int mdb_kallsyms(char *str, int (*print)(char *s, ...)) >> { >> register loff_t pos = 0; >> register struct kallsym_iter *iter = &mdb_iter; >> >> if (!print) >> return 0; >> >> // set to beginning of the kallsyms list >> reset_iter(iter, 0); >> while (1) >> { >> // search the kallsyms list >> if (!update_iter(iter, pos++)) >> break; >> >> if (!iter->name[0]) >> continue; >> >> // if an exclusion search was specified, skip non-matching entries >> if (str && *str && !strstr(iter->name, str)) >> continue; >> >> if (iter->module_name[0]) >> { >> if (print("%0*lx %c %s [%s]\n", (int)(2*sizeof(void*)), >> iter->value, iter->type, iter->name, >> iter->module_name)) >> return 1; >> } >> else >> { >> if (print("%0*lx %c %s\n", (int)(2*sizeof(void*)), >> iter->value, iter->type, iter->name)) >> return 1; >> } >> } >> return 0; >> } >> EXPORT_SYMBOL_GPL(mdb_kallsyms); >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/