Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761970Ab3DCIb4 (ORCPT ); Wed, 3 Apr 2013 04:31:56 -0400 Received: from seldrel01.sonyericsson.com ([212.209.106.2]:8701 "EHLO seldrel01.sonyericsson.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761524Ab3DCI3P (ORCPT ); Wed, 3 Apr 2013 04:29:15 -0400 From: To: CC: , , , , , , , Toby Collett Subject: [PATCH 1/4] kprobes: delay blacklist symbol lookup until we actually need it Date: Wed, 3 Apr 2013 10:28:51 +0200 Message-ID: <1364977734-32267-2-git-send-email-oskar.andero@sonymobile.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1364977734-32267-1-git-send-email-oskar.andero@sonymobile.com> References: <1364977734-32267-1-git-send-email-oskar.andero@sonymobile.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4913 Lines: 158 From: Toby Collett The symbol lookup can take a long time and kprobes is initialised very early in boot, so delay symbol lookup until the blacklist is first used. Reviewed-by: Radovan Lekanovic Signed-off-by: Toby Collett Signed-off-by: Oskar Andero --- kernel/kprobes.c | 91 +++++++++++++++++++++++++++++++++----------------------- 1 file changed, 53 insertions(+), 38 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index e35be53..71a6bee 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -68,6 +68,7 @@ #endif static int kprobes_initialized; +static int kprobe_blacklist_initialized; static struct hlist_head kprobe_table[KPROBE_TABLE_SIZE]; static struct hlist_head kretprobe_inst_table[KPROBE_TABLE_SIZE]; @@ -102,6 +103,53 @@ static struct kprobe_blackpoint kprobe_blacklist[] = { {NULL} /* Terminator */ }; +/* it can take some time ( > 100ms ) to initialise the + * blacklist so we delay this until we actually need it + */ +static void init_kprobe_blacklist(void) +{ + int i; + unsigned long offset = 0, size = 0; + char *modname, namebuf[128]; + const char *symbol_name; + void *addr; + struct kprobe_blackpoint *kb; + + /* + * Lookup and populate the kprobe_blacklist. + * + * Unlike the kretprobe blacklist, we'll need to determine + * the range of addresses that belong to the said functions, + * since a kprobe need not necessarily be at the beginning + * of a function. + */ + for (kb = kprobe_blacklist; kb->name != NULL; kb++) { + kprobe_lookup_name(kb->name, addr); + if (!addr) + continue; + + kb->start_addr = (unsigned long)addr; + symbol_name = kallsyms_lookup(kb->start_addr, + &size, &offset, &modname, namebuf); + if (!symbol_name) + kb->range = 0; + else + kb->range = size; + } + + if (kretprobe_blacklist_size) { + /* lookup the function address from its name */ + for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { + kprobe_lookup_name(kretprobe_blacklist[i].name, + kretprobe_blacklist[i].addr); + if (!kretprobe_blacklist[i].addr) + printk("kretprobe: lookup failed: %s\n", + kretprobe_blacklist[i].name); + } + } + kprobe_blacklist_initialized = 1; +} + #ifdef __ARCH_WANT_KPROBES_INSN_SLOT /* * kprobe->ainsn.insn points to the copy of the instruction to be @@ -1331,6 +1379,9 @@ static int __kprobes in_kprobes_functions(unsigned long addr) if (addr >= (unsigned long)__kprobes_text_start && addr < (unsigned long)__kprobes_text_end) return -EINVAL; + + if (!kprobe_blacklist_initialized) + init_kprobe_blacklist(); /* * If there exists a kprobe_blacklist, verify and * fail any probe registration in the prohibited area @@ -1816,6 +1867,8 @@ int __kprobes register_kretprobe(struct kretprobe *rp) void *addr; if (kretprobe_blacklist_size) { + if (!kprobe_blacklist_initialized) + init_kprobe_blacklist(); addr = kprobe_addr(&rp->kp); if (IS_ERR(addr)) return PTR_ERR(addr); @@ -2065,11 +2118,6 @@ static struct notifier_block kprobe_module_nb = { static int __init init_kprobes(void) { int i, err = 0; - unsigned long offset = 0, size = 0; - char *modname, namebuf[128]; - const char *symbol_name; - void *addr; - struct kprobe_blackpoint *kb; /* FIXME allocate the probe table, currently defined statically */ /* initialize all list heads */ @@ -2079,39 +2127,6 @@ static int __init init_kprobes(void) raw_spin_lock_init(&(kretprobe_table_locks[i].lock)); } - /* - * Lookup and populate the kprobe_blacklist. - * - * Unlike the kretprobe blacklist, we'll need to determine - * the range of addresses that belong to the said functions, - * since a kprobe need not necessarily be at the beginning - * of a function. - */ - for (kb = kprobe_blacklist; kb->name != NULL; kb++) { - kprobe_lookup_name(kb->name, addr); - if (!addr) - continue; - - kb->start_addr = (unsigned long)addr; - symbol_name = kallsyms_lookup(kb->start_addr, - &size, &offset, &modname, namebuf); - if (!symbol_name) - kb->range = 0; - else - kb->range = size; - } - - if (kretprobe_blacklist_size) { - /* lookup the function address from its name */ - for (i = 0; kretprobe_blacklist[i].name != NULL; i++) { - kprobe_lookup_name(kretprobe_blacklist[i].name, - kretprobe_blacklist[i].addr); - if (!kretprobe_blacklist[i].addr) - printk("kretprobe: lookup failed: %s\n", - kretprobe_blacklist[i].name); - } - } - #if defined(CONFIG_OPTPROBES) #if defined(__ARCH_WANT_KPROBES_INSN_SLOT) /* Init kprobe_optinsn_slots */ -- 1.8.1.5 -- 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/