From patchwork Tue Aug 13 11:53:34 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jinjie Ruan X-Patchwork-Id: 13761874 Received: from szxga05-in.huawei.com (szxga05-in.huawei.com [45.249.212.191]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4CDBB1991D2; Tue, 13 Aug 2024 11:47:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.249.212.191 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723549622; cv=none; b=VXPR7RbeL91yljF5MnC1X4GKI/EavYTrQFqLsTC8/iw8c9rxYxrqLJEXhM5cM4ac096U+Oa9na0Dkdc9uoz2+ZmbYvE9wsX05LfyKy4LyLgAr3qhXBzE8AOWdP78UFBl/tBOeYbra2UcLtArlvB5mWKsUGAuwjsRoEkvJXH96PE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723549622; c=relaxed/simple; bh=DYwOX3bvc2I/Wodi76K+HqyzxK2YKkr2FDXmZ7RYW28=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=MhuoLdjO4/9uWoz5MLgAdUZLYV7EeimjPPbmaeG40LeEsF4lfUKZGj4V8ZkP19tLMbOMc8FaaeKQ7q05wNyYhym742di8Jb3EcGr+WBNQ6s4gIBzfPMB7tZEdDA9YigadAf04bdZSHWbZ0+XYQWOsrHC5kk3mwb+1IVX+IvlBsM= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.191 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.88.234]) by szxga05-in.huawei.com (SkyGuard) with ESMTP id 4WjqKJ6D1pz1HGQj; Tue, 13 Aug 2024 19:43:48 +0800 (CST) Received: from kwepemi100008.china.huawei.com (unknown [7.221.188.57]) by mail.maildlp.com (Postfix) with ESMTPS id 2DC9E140134; Tue, 13 Aug 2024 19:46:52 +0800 (CST) Received: from huawei.com (10.90.53.73) by kwepemi100008.china.huawei.com (7.221.188.57) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Tue, 13 Aug 2024 19:46:51 +0800 From: Jinjie Ruan To: , , , , , , , , CC: Subject: [PATCH 3/3] kprobes: Cleanup collect_one_slot() and __disable_kprobe() Date: Tue, 13 Aug 2024 19:53:34 +0800 Message-ID: <20240813115334.3922580-4-ruanjinjie@huawei.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240813115334.3922580-1-ruanjinjie@huawei.com> References: <20240813115334.3922580-1-ruanjinjie@huawei.com> Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: dggems701-chm.china.huawei.com (10.3.19.178) To kwepemi100008.china.huawei.com (7.221.188.57) If kip->nused is not zero, collect_one_slot() return false, otherwise do a lot of linked list operations, reverse the processing order to make the code if nesting more concise. __disable_kprobe() is the same as well. Signed-off-by: Jinjie Ruan --- kernel/kprobes.c | 79 ++++++++++++++++++++++++------------------------ 1 file changed, 40 insertions(+), 39 deletions(-) diff --git a/kernel/kprobes.c b/kernel/kprobes.c index ca3fa8652c49..98d71a5acb72 100644 --- a/kernel/kprobes.c +++ b/kernel/kprobes.c @@ -206,29 +206,29 @@ static bool collect_one_slot(struct kprobe_insn_page *kip, int idx) { kip->slot_used[idx] = SLOT_CLEAN; kip->nused--; - if (kip->nused == 0) { + if (kip->nused != 0) + return false; + + /* + * Page is no longer in use. Free it unless + * it's the last one. We keep the last one + * so as not to have to set it up again the + * next time somebody inserts a probe. + */ + if (!list_is_singular(&kip->list)) { /* - * Page is no longer in use. Free it unless - * it's the last one. We keep the last one - * so as not to have to set it up again the - * next time somebody inserts a probe. + * Record perf ksymbol unregister event before removing + * the page. */ - if (!list_is_singular(&kip->list)) { - /* - * Record perf ksymbol unregister event before removing - * the page. - */ - perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, - (unsigned long)kip->insns, PAGE_SIZE, true, - kip->cache->sym); - list_del_rcu(&kip->list); - synchronize_rcu(); - kip->cache->free(kip->insns); - kfree(kip); - } - return true; + perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, + (unsigned long)kip->insns, PAGE_SIZE, true, + kip->cache->sym); + list_del_rcu(&kip->list); + synchronize_rcu(); + kip->cache->free(kip->insns); + kfree(kip); } - return false; + return true; } static int collect_garbage_slots(struct kprobe_insn_cache *c) @@ -1725,28 +1725,29 @@ static struct kprobe *__disable_kprobe(struct kprobe *p) if (unlikely(orig_p == NULL)) return ERR_PTR(-EINVAL); - if (!kprobe_disabled(p)) { - /* Disable probe if it is a child probe */ - if (p != orig_p) - p->flags |= KPROBE_FLAG_DISABLED; + if (kprobe_disabled(p)) + return orig_p; - /* Try to disarm and disable this/parent probe */ - if (p == orig_p || aggr_kprobe_disabled(orig_p)) { - /* - * Don't be lazy here. Even if 'kprobes_all_disarmed' - * is false, 'orig_p' might not have been armed yet. - * Note arm_all_kprobes() __tries__ to arm all kprobes - * on the best effort basis. - */ - if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) { - ret = disarm_kprobe(orig_p, true); - if (ret) { - p->flags &= ~KPROBE_FLAG_DISABLED; - return ERR_PTR(ret); - } + /* Disable probe if it is a child probe */ + if (p != orig_p) + p->flags |= KPROBE_FLAG_DISABLED; + + /* Try to disarm and disable this/parent probe */ + if (p == orig_p || aggr_kprobe_disabled(orig_p)) { + /* + * Don't be lazy here. Even if 'kprobes_all_disarmed' + * is false, 'orig_p' might not have been armed yet. + * Note arm_all_kprobes() __tries__ to arm all kprobes + * on the best effort basis. + */ + if (!kprobes_all_disarmed && !kprobe_disabled(orig_p)) { + ret = disarm_kprobe(orig_p, true); + if (ret) { + p->flags &= ~KPROBE_FLAG_DISABLED; + return ERR_PTR(ret); } - orig_p->flags |= KPROBE_FLAG_DISABLED; } + orig_p->flags |= KPROBE_FLAG_DISABLED; } return orig_p;