Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751481AbaGBHAn (ORCPT ); Wed, 2 Jul 2014 03:00:43 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:59426 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205AbaGBHAk (ORCPT ); Wed, 2 Jul 2014 03:00:40 -0400 Subject: [PATCH v5 2/2] [BUGFIX] kprobes: Fix "Failed to find blacklist" error on ia64 and ppc64 From: Masami Hiramatsu To: Benjamin Herrenschmidt , Paul Mackerras , Tony Luck Cc: Jeremy Fitzhardinge , linux-ia64@vger.kernel.org, sparse@chrisli.org, "H. Peter Anvin" , Ingo Molnar , linux-tip-commits@vger.kernel.org, Michael Ellerman , akataria@vmware.com, anil.s.keshavamurthy@intel.com, "Suzuki K. Poulose" , Fenghua Yu , Arnd Bergmann , Rusty Russell , Chris Wright , yrl.pp-manager.tt@hitachi.com, Thomas Gleixner , Tony Luck , Kevin Hao , Ananth N Mavinakayanahalli , linuxppc-dev@lists.ozlabs.org, rdunlap@infradead.org, Linux Kernel Mailing List , dl9pf@gmx.de, Andrew Morton , Linus Torvalds , "David S. Miller" Date: Wed, 02 Jul 2014 07:00:29 +0000 Message-ID: <20140702070029.14689.18485.stgit@kbuild-fedora.novalocal> In-Reply-To: <1404276081.7254.1.camel@concordia> References: <1404276081.7254.1.camel@concordia> User-Agent: StGit/0.17-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On ia64 and ppc64, the function pointer does not point the entry address of the function, but the address of function discriptor (which contains the entry address and misc data.) Since the kprobes passes the function pointer stored by NOKPROBE_SYMBOL() to kallsyms_lookup_size_offset() for initalizing its blacklist, it fails and reports many errors as below. Failed to find blacklist 0001013168300000 Failed to find blacklist 0001013000f0a000 Failed to find blacklist 000101315f70a000 Failed to find blacklist 000101324c80a000 Failed to find blacklist 0001013063f0a000 Failed to find blacklist 000101327800a000 Failed to find blacklist 0001013277f0a000 Failed to find blacklist 000101315a70a000 Failed to find blacklist 0001013277e0a000 Failed to find blacklist 000101305a20a000 Failed to find blacklist 0001013277d0a000 Failed to find blacklist 00010130bdc0a000 Failed to find blacklist 00010130dc20a000 Failed to find blacklist 000101309a00a000 Failed to find blacklist 0001013277c0a000 Failed to find blacklist 0001013277b0a000 Failed to find blacklist 0001013277a0a000 Failed to find blacklist 000101327790a000 Failed to find blacklist 000101303140a000 Failed to find blacklist 0001013a3280a000 To fix this bug, this introduces function_entry() macro to retrieve the entry address from the given function pointer, and uses for kallsyms_lookup_size_offset() while initializing blacklist. Changes in v5: - Use arch_deref_entry_point() instead of function_entry(). Changes in v4: - Add kernel_text_address() check for verifying the address. - Moved on the latest linus tree. Changes in v3: - Fix a bug to get blacklist address based on function entry instead of function descriptor. (Suzuki's work, Thanks!) Changes in V2: - Use function_entry() macro when lookin up symbols instead of storing it. - Update for the latest -next. Signed-off-by: Masami Hiramatsu Reported-by: Tony Luck Tested-by: Tony Luck Cc: Michael Ellerman Cc: Suzuki K. Poulose Cc: Tony Luck Cc: Fenghua Yu Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Ananth N Mavinakayanahalli Cc: Kevin Hao Cc: linux-ia64@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org --- kernel/kprobes.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index 3214289..ec370cc 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -32,6 +32,7 @@ * added function-return probes. */ #include +#include #include #include #include @@ -2037,19 +2038,23 @@ static int __init populate_kprobe_blacklist(unsigned long *start, { unsigned long *iter; struct kprobe_blacklist_entry *ent; - unsigned long offset = 0, size = 0; + unsigned long entry, offset = 0, size = 0; for (iter = start; iter < end; iter++) { - if (!kallsyms_lookup_size_offset(*iter, &size, &offset)) { - pr_err("Failed to find blacklist %p\n", (void *)*iter); + entry = arch_deref_entry_point((void *)*iter); + + if (!kernel_text_address(entry) || + !kallsyms_lookup_size_offset(entry, &size, &offset)) { + pr_err("Failed to find blacklist at %p\n", + (void *)entry); continue; } ent = kmalloc(sizeof(*ent), GFP_KERNEL); if (!ent) return -ENOMEM; - ent->start_addr = *iter; - ent->end_addr = *iter + size; + ent->start_addr = entry; + ent->end_addr = entry + size; INIT_LIST_HEAD(&ent->list); list_add_tail(&ent->list, &kprobe_blacklist); } -- 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/