From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+ExK7PWNGUYaykcB7X7om3l/jqzyIMlAlolVGBXXAy8LOPTTChyHMYO9y+erRiDhFht+4X ARC-Seal: i=1; a=rsa-sha256; t=1523393466; cv=none; d=google.com; s=arc-20160816; b=05J1oUdfcGcnECiprJ7DvevT1eozxkyGV8y3ETq6dGcFQgImjsQDC4uBTMoJ2k8IdT 7DJ86TR5hzP3gKbpWYpIWQ3ix5+W+O1+O7FwHg9sKi5EedzRBxT9JUXmog6hTkwCCfVf VA86RhyN00jEWmz6HwBUcbjymqYYSX848lmnmewEIxQenjmqVtZif69qz8kKp162VeAl BuXmhfUSwoPVfLxgJfFEwn5aTB/wwKbdkZiQ9eX+nBaQPy34BQy5NC4r5Fc8D3LMaxV3 JDlkdKF5XJlHMAJS0FihcAHxNr1Sd3vbJD8Jwo4j9F9uZtBQ3I6KDE/nu1O8k11/vcUc TZJw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding :content-language:in-reply-to:mime-version:user-agent:date :message-id:organization:from:references:cc:to:subject :arc-authentication-results; bh=T2svMJR48ChmquqpnyJEehQ58/FJ5EjX/fb0WXNoXEI=; b=QaiAwZf9kZczhsQlfWg9LsJYLQWzuapYh4/lutOztM3AOC+GZIbFCsagryrjdB+ixz WO5M+sSPikAzS7Jo1PejQe6cHbdxRGKK18SGFJkjsZ7rIYfZ9uF5n6yGFTwE7YW718Z7 9jdlfNWTcCqAPDFv9BwV9GqKNCj5ZM5iFn5QuvTjrukwgf9mrntJZSZ01mXV27AImHNB LC6IpPV4Fkx+n+KGZLeLqLe1s4V84fHfkJVR2lkI9lYGZbdZsTtOWE8sl/F38zXkgopo 3VFsnJrgsHpCEYyhylMvTcIUhXKuMa3rF4uPv0Q7M1bK1RGdsH3UjRtCGsuZOfK556aH sbYQ== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751770AbeDJUux (ORCPT ); Tue, 10 Apr 2018 16:50:53 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:49230 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751546AbeDJUuw (ORCPT ); Tue, 10 Apr 2018 16:50:52 -0400 Subject: Re: [PATCH v2] selftests/livepatch: introduce tests To: Josh Poimboeuf Cc: live-patching@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Jiri Kosina , Petr Mladek , Miroslav Benes , =?UTF-8?Q?Libor_Pech=c3=a1=c4=8dek?= , Nicolai Stange , Artem Savkov References: <1523373354-10801-1-git-send-email-joe.lawrence@redhat.com> <1523373354-10801-2-git-send-email-joe.lawrence@redhat.com> <20180410200059.loy3hw6tcwdi4m5z@treble> From: Joe Lawrence Organization: Red Hat Message-ID: Date: Tue, 10 Apr 2018 16:50:51 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: <20180410200059.loy3hw6tcwdi4m5z@treble> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kselftest-owner@vger.kernel.org X-Mailing-List: linux-kselftest@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597372767626625774?= X-GMAIL-MSGID: =?utf-8?q?1597393827813782407?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On 04/10/2018 04:00 PM, Josh Poimboeuf wrote: > On Tue, Apr 10, 2018 at 11:15:54AM -0400, Joe Lawrence wrote: >> +static void test_klp_shadow_vars_exit(void) >> +{ >> +} >> + >> +module_init(test_klp_shadow_vars_init); >> +module_init(test_klp_shadow_vars_exit); > > For this last line, s/module_init/module_exit/, though I think the exit > function can just be removed altogether? D'oh workspace / git user error, I posted an older version :( But the exit function seems to be required if an init function is provided. Here I omitted the exit function: % modprobe test_klp_shadow_vars % lsmod | grep test_klp_shadow_vars test_klp_shadow_vars 16384 0 % rmmod test_klp_shadow_vars rmmod: ERROR: could not remove 'test_klp_shadow_vars': Device or resource busy rmmod: ERROR: could not remove module test_klp_shadow_vars: Device or resource busy and from kernel/module.c SYSCALL_DEFINE2(delete_module, const char __user *, name_user, unsigned int, flags) ... /* If it has an init func, it must have an exit func to unload*/ if (mod->init && !mod->exit) { forced = try_force_unload(flags); if (!forced) { /* This module can't be removed */ ret = -EBUSY; goto out; } } ... > > Also I get the following bug (run on latest Linus master + Petr's two > patch sets): > > [ 106.302072] % modprobe test_klp_shadow_vars > [ 106.311165] test_klp_shadow_vars: klp_shadow_get(obj=PTR5, id=0x1234) = PTR0 > [ 106.313080] test_klp_shadow_vars: got expected NULL result > [ 106.314811] BUG: sleeping function called from invalid context at mm/slab.h:421 > [ 106.316518] in_atomic(): 1, irqs_disabled(): 1, pid: 2254, name: modprobe > [ 106.318107] 1 lock held by modprobe/2254: > [ 106.319332] #0: 00000000d0851080 (klp_shadow_lock){....}, at: __klp_shadow_get_or_alloc+0x88/0x1b0 > [ 106.321220] irq event stamp: 4408 > [ 106.322176] hardirqs last enabled at (4407): [] console_unlock+0x44e/0x680 > [ 106.323598] hardirqs last disabled at (4408): [] _raw_spin_lock_irqsave+0x27/0x90 > [ 106.325041] softirqs last enabled at (4404): [] __do_softirq+0x39b/0x4fc > [ 106.326469] softirqs last disabled at (4367): [] irq_exit+0xe0/0xf0 > [ 106.327901] Preemption disabled at: > [ 106.327905] [] __klp_shadow_get_or_alloc+0x88/0x1b0 > [ 106.330117] CPU: 7 PID: 2254 Comm: modprobe Tainted: G K 4.16.0+ #60 > [ 106.331565] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-2.fc27 04/01/2014 > [ 106.333143] Call Trace: > [ 106.334011] dump_stack+0x8e/0xd5 > [ 106.334962] ___might_sleep+0x185/0x260 > [ 106.335997] ? shadow_dtor+0x40/0x40 [test_klp_shadow_vars] > [ 106.337170] __might_sleep+0x4a/0x80 > [ 106.338137] kmem_cache_alloc_trace+0x20b/0x300 > [ 106.339183] ? ptr_id+0x5c/0xd0 [test_klp_shadow_vars] > [ 106.340341] ? shadow_dtor+0x40/0x40 [test_klp_shadow_vars] > [ 106.341506] ptr_id+0x5c/0xd0 [test_klp_shadow_vars] > [ 106.342725] shadow_ctor+0x20/0x40 [test_klp_shadow_vars] > [ 106.343998] __klp_shadow_get_or_alloc+0xc4/0x1b0 > [ 106.345184] ? shadow_dtor+0x40/0x40 [test_klp_shadow_vars] > [ 106.346494] klp_shadow_alloc+0x10/0x20 > [ 106.347583] shadow_alloc+0x28/0xa0 [test_klp_shadow_vars] > [ 106.348871] ? shadow_free_all+0x40/0x40 [test_klp_shadow_vars] > [ 106.350200] test_klp_shadow_vars_init+0x96/0x400 [test_klp_shadow_vars] > [ 106.351646] ? shadow_free_all+0x40/0x40 [test_klp_shadow_vars] > [ 106.352949] do_one_initcall+0x61/0x37f > [ 106.353963] ? rcu_read_lock_sched_held+0x79/0x80 > [ 106.355040] ? kmem_cache_alloc_trace+0x29d/0x300 > [ 106.356098] ? do_init_module+0x27/0x213 > [ 106.357090] do_init_module+0x5f/0x213 > [ 106.358047] load_module+0x2815/0x2e70 > [ 106.358992] ? vfs_read+0x12d/0x150 > [ 106.359920] SYSC_finit_module+0xfc/0x120 > [ 106.360870] ? SYSC_finit_module+0xfc/0x120 > [ 106.361839] SyS_finit_module+0xe/0x10 > [ 106.362753] do_syscall_64+0x7e/0x240 > [ 106.363645] entry_SYSCALL_64_after_hwframe+0x42/0xb7 > [ 106.364711] RIP: 0033:0x7f26d0d40b19 > [ 106.365799] RSP: 002b:00007ffee1de19a8 EFLAGS: 00000246 ORIG_RAX: 0000000000000139 > [ 106.367306] RAX: ffffffffffffffda RBX: 00005636550d54b0 RCX: 00007f26d0d40b19 > [ 106.368573] RDX: 0000000000000000 RSI: 0000563654134186 RDI: 0000000000000003 > [ 106.369950] RBP: 0000563654134186 R08: 0000000000000000 R09: 00005636550d4270 > [ 106.371164] R10: 0000000000000003 R11: 0000000000000246 R12: 0000000000000000 > [ 106.372422] R13: 00005636550d53b0 R14: 0000000000040000 R15: 00005636550d54b0 I missed Petr's commit msg note "that the constructor is called under klp_shadow_lock." I'll convert the test to use GFP_ATOMIC for this allocation. I'll also add CONFIG_PM_SLEEP_DEBUG=y to my test VM kernel .config. Any other debug option suggestions? -- Joe