From patchwork Wed Aug 15 20:30:19 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Rick Edgecombe X-Patchwork-Id: 10566813 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 781F414E1 for ; Wed, 15 Aug 2018 20:35:09 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3A4612ACA9 for ; Wed, 15 Aug 2018 20:35:09 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2DC0F2AD66; Wed, 15 Aug 2018 20:35:09 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.2 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from mother.openwall.net (mother.openwall.net [195.42.179.200]) by mail.wl.linuxfoundation.org (Postfix) with SMTP id 394962ACA9 for ; Wed, 15 Aug 2018 20:35:08 +0000 (UTC) Received: (qmail 15731 invoked by uid 550); 15 Aug 2018 20:34:43 -0000 Mailing-List: contact kernel-hardening-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Delivered-To: mailing list kernel-hardening@lists.openwall.com Received: (qmail 15629 invoked from network); 15 Aug 2018 20:34:36 -0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,244,1531810800"; d="scan'208";a="224930399" From: Rick Edgecombe To: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-hardening@lists.openwall.com, daniel@iogearbox.net, jannh@google.com, keescook@chromium.org Cc: kristen@linux.intel.com, dave.hansen@intel.com, arjan@linux.intel.com, Rick Edgecombe Subject: [PATCH v3 3/3] vmalloc: Add debugfs modfraginfo Date: Wed, 15 Aug 2018 13:30:19 -0700 Message-Id: <1534365020-18943-4-git-send-email-rick.p.edgecombe@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1534365020-18943-1-git-send-email-rick.p.edgecombe@intel.com> References: <1534365020-18943-1-git-send-email-rick.p.edgecombe@intel.com> X-Virus-Scanned: ClamAV using ClamSMTP Add debugfs file "modfraginfo" for providing info on module space fragmentation. This can be used for determining if loadable module randomization is causing any problems for extreme module loading situations, like huge numbers of modules or extremely large modules. Sample output when KASLR is enabled and X86_64 is configured: Largest free space: 897912 kB Total free space: 1025424 kB Allocations in backup area: 0 Sample output when just X86_64: Largest free space: 897912 kB Total free space: 1025424 kB Signed-off-by: Rick Edgecombe --- mm/vmalloc.c | 89 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 88 insertions(+), 1 deletion(-) diff --git a/mm/vmalloc.c b/mm/vmalloc.c index fb85ec9..cb55138 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -18,6 +18,7 @@ #include #include #include +#include #include #include #include @@ -33,6 +34,7 @@ #include #include +#include #include #include @@ -2925,7 +2927,92 @@ static int __init proc_vmalloc_init(void) proc_create_seq("vmallocinfo", 0400, NULL, &vmalloc_op); return 0; } -module_init(proc_vmalloc_init); +#else +static int __init proc_vmalloc_init(void) +{ + return 0; +} +#endif + +#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64) +static int modulefraginfo_debug_show(struct seq_file *m, void *v) +{ + unsigned long last_end = MODULES_VADDR; + unsigned long total_free = 0; + unsigned long largest_free = 0; + unsigned long backup_cnt = 0; + unsigned long gap; + struct vmap_area *prev, *cur = NULL; + + spin_lock(&vmap_area_lock); + + if (!pvm_find_next_prev(MODULES_VADDR, &cur, &prev) || !cur) + goto done; + + for (; cur->va_end <= MODULES_END; cur = list_next_entry(cur, list)) { + /* Don't count areas that are marked to be lazily freed */ + if ((cur->flags & VM_LAZY_FREE)) + continue; + + if (cur->va_start >= MODULES_VADDR + MODULES_RAND_LEN) + backup_cnt++; + gap = cur->va_start - last_end; + if (gap > largest_free) + largest_free = gap; + total_free += gap; + last_end = cur->va_end; + + if (list_is_last(&cur->list, &vmap_area_list)) + break; + } + +done: + gap = (MODULES_END - last_end); + if (gap > largest_free) + largest_free = gap; + total_free += gap; + + spin_unlock(&vmap_area_lock); + seq_printf(m, "\tLargest free space:\t%lu kB\n", largest_free / 1024); + seq_printf(m, "\t Total free space:\t%lu kB\n", total_free / 1024); + + if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled()) + seq_printf(m, "Allocations in backup area:\t%lu\n", backup_cnt); + + return 0; +} + +static int proc_module_frag_debug_open(struct inode *inode, struct file *file) +{ + return single_open(file, modulefraginfo_debug_show, NULL); +} + +static const struct file_operations debug_module_frag_operations = { + .open = proc_module_frag_debug_open, + .read = seq_read, + .llseek = seq_lseek, + .release = single_release, +}; + +static void __init debug_modfrag_init(void) +{ + debugfs_create_file("modfraginfo", 0400, NULL, NULL, + &debug_module_frag_operations); +} +#else /* defined(CONFIG_DEBUG_FS) && defined(CONFIG_X86_64) */ +static void __init debug_modfrag_init(void) +{ +} #endif +#if defined(CONFIG_DEBUG_FS) || defined(CONFIG_PROC_FS) +static int __init info_vmalloc_init(void) +{ + proc_vmalloc_init(); + debug_modfrag_init(); + return 0; +} + +module_init(info_vmalloc_init); +#endif