From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.4 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10CB2C352A3 for ; Tue, 11 Feb 2020 12:57:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8AA852082F for ; Tue, 11 Feb 2020 12:57:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=yandex-team.ru header.i=@yandex-team.ru header.b="gELgADqo" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728685AbgBKM5t (ORCPT ); Tue, 11 Feb 2020 07:57:49 -0500 Received: from forwardcorp1p.mail.yandex.net ([77.88.29.217]:44244 "EHLO forwardcorp1p.mail.yandex.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727567AbgBKM5t (ORCPT ); Tue, 11 Feb 2020 07:57:49 -0500 Received: from mxbackcorp1j.mail.yandex.net (mxbackcorp1j.mail.yandex.net [IPv6:2a02:6b8:0:1619::162]) by forwardcorp1p.mail.yandex.net (Yandex) with ESMTP id 146C92E1519; Tue, 11 Feb 2020 15:57:44 +0300 (MSK) Received: from iva8-88b7aa9dc799.qloud-c.yandex.net (iva8-88b7aa9dc799.qloud-c.yandex.net [2a02:6b8:c0c:77a0:0:640:88b7:aa9d]) by mxbackcorp1j.mail.yandex.net (mxbackcorp/Yandex) with ESMTP id pJkVXctvSi-vgH8b22C; Tue, 11 Feb 2020 15:57:44 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex-team.ru; s=default; t=1581425864; bh=NHH0wtXonm288LY4yrqGyPS2/VE8CjGul0VISCue9x4=; h=In-Reply-To:Message-ID:From:Date:References:To:Subject:Cc; b=gELgADqoLrkcq6kDQ9t+fS9PPRyMrm9o8U0sORmPdO5LRThEa9a499DSOcw1D2mcI 3Wvr8niyvf6hhXT8Vnbs8K5Q5HjlKL9van2W4yyxmBmh1OsNra4HtOVK7WgJhhNr7j yHqywRajC4jKW+A4RI+EpYJ+HRqkwZX0HQ4qSSII= Authentication-Results: mxbackcorp1j.mail.yandex.net; dkim=pass header.i=@yandex-team.ru Received: from dynamic-red.dhcp.yndx.net (dynamic-red.dhcp.yndx.net [2a02:6b8:0:40c:8448:fbcc:1dac:c863]) by iva8-88b7aa9dc799.qloud-c.yandex.net (smtpcorp/Yandex) with ESMTPSA id KbadN9TSsO-vgVGiSwv; Tue, 11 Feb 2020 15:57:42 +0300 (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (Client certificate not present) Subject: Re: [PATCH] lib/test_lockup: test module to generate lockups To: Kees Cook Cc: Andrew Morton , linux-kernel@vger.kernel.org, Sasha Levin , Petr Mladek , Peter Zijlstra , Greg Kroah-Hartman , Steven Rostedt , Sergey Senozhatsky , Dmitry Monakhov References: <158132859146.2797.525923171323227836.stgit@buzz> <202002101725.EE6D5A6@keescook> From: Konstantin Khlebnikov Message-ID: <5e5ee6b7-68a9-1bcc-66c5-814e40a627be@yandex-team.ru> Date: Tue, 11 Feb 2020 15:57:42 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <202002101725.EE6D5A6@keescook> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-CA Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/02/2020 04.26, Kees Cook wrote: > On Mon, Feb 10, 2020 at 12:56:31PM +0300, Konstantin Khlebnikov wrote: >> CONFIG_TEST_LOCKUP=m adds module "test_lockup" that helps to make sure >> that watchdogs and lockup detectors are working properly. > > Isn't this all already possible with CONFIG_LKDTM ? Yep, LKDTM covers some cases. But they are unrecoverable. It seems LKDTM is more like a fixed set of unit tests while test_lockup is a flexible tool for stress load. > > -Kees > >> >> Depending on module parameters test_lockup could emulate soft or hard >> lockup, "hung task", hold arbitrary lock, allocate bunch of pages. >> >> Also it could generate series of lockups with cooling-down periods, >> in this way it could be used as "ping" for locks or page allocator. >> Loop checks signals between iteration thus could be stopped by ^C. >> >> >> # modinfo test_lockup >> ... >> parm: time_secs:lockup time in seconds, default 0 (uint) >> parm: time_nsecs:nanoseconds part of lockup time, default 0 (uint) >> parm: cooldown_secs:cooldown time between iterations in seconds, default 0 (uint) >> parm: cooldown_nsecs:nanoseconds part of cooldown, default 0 (uint) >> parm: iterations:lockup iterations, default 1 (uint) >> parm: all_cpus:trigger lockup at all cpus at once (bool) >> parm: state:wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state (charp) >> parm: use_hrtimer:use high-resolution timer for sleeping (bool) >> parm: iowait:account sleep time as iowait (bool) >> parm: lock_read:lock read-write locks for read (bool) >> parm: lock_single:acquire locks only at one cpu (bool) >> parm: reacquire_locks:release and reacquire locks/irq/preempt between iterations (bool) >> parm: touch_softlockup:touch soft-lockup watchdog between iterations (bool) >> parm: touch_hardlockup:touch hard-lockup watchdog between iterations (bool) >> parm: call_cond_resched:call cond_resched() between iterations (bool) >> parm: measure_lock_wait:measure lock wait time (bool) >> parm: lock_wait_threshold:print lock wait time longer than this in nanoseconds, default off (ulong) >> parm: disable_irq:disable interrupts: generate hard-lockups (bool) >> parm: disable_softirq:disable bottom-half irq handlers (bool) >> parm: disable_preempt:disable preemption: generate soft-lockups (bool) >> parm: lock_rcu:grab rcu_read_lock: generate rcu stalls (bool) >> parm: lock_mmap_sem:lock mm->mmap_sem: block procfs interfaces (bool) >> parm: lock_rwsem_ptr:lock rw_semaphore at address (ulong) >> parm: lock_mutex_ptr:lock mutex at address (ulong) >> parm: lock_spinlock_ptr:lock spinlock at address (ulong) >> parm: lock_rwlock_ptr:lock rwlock at address (ulong) >> parm: alloc_pages_nr:allocate and free pages under locks (uint) >> parm: alloc_pages_order:page order to allocate (uint) >> parm: alloc_pages_gfp:allocate pages with this gfp_mask, default GFP_KERNEL (uint) >> parm: alloc_pages_atomic:allocate pages with GFP_ATOMIC (bool) >> parm: reallocate_pages:free and allocate pages between iterations (bool) >> >> >> Parameters for locking by address are unsafe and taints kernel. With >> CONFIG_DEBUG_SPINLOCK=y they at least check magics for embedded spinlocks. >> >> >> Examples: >> >> task hang in D-state: >> modprobe test_lockup time_secs=1 iterations=60 state=D >> >> task hang in io-wait D-state: >> modprobe test_lockup time_secs=1 iterations=60 state=D iowait >> >> softlockup: >> modprobe test_lockup time_secs=1 iterations=60 state=R >> >> hardlockup: >> modprobe test_lockup time_secs=1 iterations=60 state=R disable_irq >> >> system-wide hardlockup: >> modprobe test_lockup time_secs=1 iterations=60 state=R \ >> disable_irq all_cpus >> >> rcu stall: >> modprobe test_lockup time_secs=1 iterations=60 state=R \ >> lock_rcu touch_softlockup >> >> lock mmap_sem / block procfs interfaces: >> modprobe test_lockup time_secs=1 iterations=60 state=S lock_mmap_sem >> >> lock tasklist_lock for read / block forks: >> TASKLIST_LOCK=$(awk '$3 == "tasklist_lock" {print "0x"$1}' /proc/kallsyms) >> modprobe test_lockup time_secs=1 iterations=60 state=R \ >> disable_irq lock_read lock_rwlock_ptr=$TASKLIST_LOCK >> >> lock namespace_sem / block vfs mount operations: >> NAMESPACE_SEM=$(awk '$3 == "namespace_sem" {print "0x"$1}' /proc/kallsyms) >> modprobe test_lockup time_secs=1 iterations=60 state=S \ >> lock_rwsem_ptr=$NAMESPACE_SEM >> >> lock cgroup mutex / block cgroup operations: >> CGROUP_MUTEX=$(awk '$3 == "cgroup_mutex" {print "0x"$1}' /proc/kallsyms) >> modprobe test_lockup time_secs=1 iterations=60 state=S \ >> lock_mutex_ptr=$CGROUP_MUTEX >> >> ping cgroup_mutex every second and measure maximum lock wait time: >> modprobe test_lockup cooldown_secs=1 iterations=60 state=S \ >> lock_mutex_ptr=$CGROUP_MUTEX reacquire_locks measure_lock_wait >> >> Signed-off-by: Konstantin Khlebnikov >> --- >> lib/Kconfig.debug | 12 + >> lib/Makefile | 1 >> lib/test_lockup.c | 554 +++++++++++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 567 insertions(+) >> create mode 100644 lib/test_lockup.c >> >> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug >> index 69def4a9df00..8feaf71dab15 100644 >> --- a/lib/Kconfig.debug >> +++ b/lib/Kconfig.debug >> @@ -978,6 +978,18 @@ config WQ_WATCHDOG >> state. This can be configured through kernel parameter >> "workqueue.watchdog_thresh" and its sysfs counterpart. >> >> +config TEST_LOCKUP >> + tristate "Test module to generate lockups" >> + help >> + This builds the "test_lockup" module that helps to make sure >> + that watchdogs and lockup detectors are working properly. >> + >> + Depending on module parameters it could emulate soft or hard >> + lockup, "hung task", or locking arbitrary lock for a long time. >> + Also it could generate series of lockups with cooling-down periods. >> + >> + If unsure, say N. >> + >> endmenu # "Debug lockups and hangs" >> >> menu "Scheduler Debugging" >> diff --git a/lib/Makefile b/lib/Makefile >> index 5d64890d6b6a..b5372a83ebe2 100644 >> --- a/lib/Makefile >> +++ b/lib/Makefile >> @@ -89,6 +89,7 @@ obj-$(CONFIG_TEST_OBJAGG) += test_objagg.o >> obj-$(CONFIG_TEST_STACKINIT) += test_stackinit.o >> obj-$(CONFIG_TEST_BLACKHOLE_DEV) += test_blackhole_dev.o >> obj-$(CONFIG_TEST_MEMINIT) += test_meminit.o >> +obj-$(CONFIG_TEST_LOCKUP) += test_lockup.o >> >> obj-$(CONFIG_TEST_LIVEPATCH) += livepatch/ >> >> diff --git a/lib/test_lockup.c b/lib/test_lockup.c >> new file mode 100644 >> index 000000000000..f91cd44ad75a >> --- /dev/null >> +++ b/lib/test_lockup.c >> @@ -0,0 +1,554 @@ >> +// SPDX-License-Identifier: GPL-2.0 >> +/* >> + * Test module to generate lockups >> + */ >> +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt >> + >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> +#include >> + >> +static unsigned int time_secs; >> +module_param(time_secs, uint, 0600); >> +MODULE_PARM_DESC(time_secs, "lockup time in seconds, default 0"); >> + >> +static unsigned int time_nsecs; >> +module_param(time_nsecs, uint, 0600); >> +MODULE_PARM_DESC(time_nsecs, "nanoseconds part of lockup time, default 0"); >> + >> +static unsigned int cooldown_secs; >> +module_param(cooldown_secs, uint, 0600); >> +MODULE_PARM_DESC(cooldown_secs, "cooldown time between iterations in seconds, default 0"); >> + >> +static unsigned int cooldown_nsecs; >> +module_param(cooldown_nsecs, uint, 0600); >> +MODULE_PARM_DESC(cooldown_nsecs, "nanoseconds part of cooldown, default 0"); >> + >> +static unsigned int iterations = 1; >> +module_param(iterations, uint, 0600); >> +MODULE_PARM_DESC(iterations, "lockup iterations, default 1"); >> + >> +static bool all_cpus; >> +module_param(all_cpus, bool, 0400); >> +MODULE_PARM_DESC(all_cpus, "trigger lockup at all cpus at once"); >> + >> +static int wait_state; >> +static char *state = "R"; >> +module_param(state, charp, 0400); >> +MODULE_PARM_DESC(state, "wait in 'R' running (default), 'D' uninterruptible, 'K' killable, 'S' interruptible state"); >> + >> +static bool use_hrtimer; >> +module_param(use_hrtimer, bool, 0400); >> +MODULE_PARM_DESC(use_hrtimer, "use high-resolution timer for sleeping"); >> + >> +static bool iowait; >> +module_param(iowait, bool, 0400); >> +MODULE_PARM_DESC(iowait, "account sleep time as iowait"); >> + >> +static bool lock_read; >> +module_param(lock_read, bool, 0400); >> +MODULE_PARM_DESC(lock_read, "lock read-write locks for read"); >> + >> +static bool lock_single; >> +module_param(lock_single, bool, 0400); >> +MODULE_PARM_DESC(lock_single, "acquire locks only at one cpu"); >> + >> +static bool reacquire_locks; >> +module_param(reacquire_locks, bool, 0400); >> +MODULE_PARM_DESC(reacquire_locks, "release and reacquire locks/irq/preempt between iterations"); >> + >> +static bool touch_softlockup; >> +module_param(touch_softlockup, bool, 0600); >> +MODULE_PARM_DESC(touch_softlockup, "touch soft-lockup watchdog between iterations"); >> + >> +static bool touch_hardlockup; >> +module_param(touch_hardlockup, bool, 0600); >> +MODULE_PARM_DESC(touch_hardlockup, "touch hard-lockup watchdog between iterations"); >> + >> +static bool call_cond_resched; >> +module_param(call_cond_resched, bool, 0600); >> +MODULE_PARM_DESC(call_cond_resched, "call cond_resched() between iterations"); >> + >> +static bool measure_lock_wait; >> +module_param(measure_lock_wait, bool, 0400); >> +MODULE_PARM_DESC(measure_lock_wait, "measure lock wait time"); >> + >> +static unsigned long lock_wait_threshold = ULONG_MAX; >> +module_param(lock_wait_threshold, ulong, 0400); >> +MODULE_PARM_DESC(lock_wait_threshold, "print lock wait time longer than this in nanoseconds, default off"); >> + >> +static bool disable_irq; >> +module_param(disable_irq, bool, 0400); >> +MODULE_PARM_DESC(disable_irq, "disable interrupts: generate hard-lockups"); >> + >> +static bool disable_softirq; >> +module_param(disable_softirq, bool, 0400); >> +MODULE_PARM_DESC(disable_softirq, "disable bottom-half irq handlers"); >> + >> +static bool disable_preempt; >> +module_param(disable_preempt, bool, 0400); >> +MODULE_PARM_DESC(disable_preempt, "disable preemption: generate soft-lockups"); >> + >> +static bool lock_rcu; >> +module_param(lock_rcu, bool, 0400); >> +MODULE_PARM_DESC(lock_rcu, "grab rcu_read_lock: generate rcu stalls"); >> + >> +static bool lock_mmap_sem; >> +module_param(lock_mmap_sem, bool, 0400); >> +MODULE_PARM_DESC(lock_mmap_sem, "lock mm->mmap_sem: block procfs interfaces"); >> + >> +static unsigned long lock_rwsem_ptr; >> +module_param_unsafe(lock_rwsem_ptr, ulong, 0400); >> +MODULE_PARM_DESC(lock_rwsem_ptr, "lock rw_semaphore at address"); >> + >> +static unsigned long lock_mutex_ptr; >> +module_param_unsafe(lock_mutex_ptr, ulong, 0400); >> +MODULE_PARM_DESC(lock_mutex_ptr, "lock mutex at address"); >> + >> +static unsigned long lock_spinlock_ptr; >> +module_param_unsafe(lock_spinlock_ptr, ulong, 0400); >> +MODULE_PARM_DESC(lock_spinlock_ptr, "lock spinlock at address"); >> + >> +static unsigned long lock_rwlock_ptr; >> +module_param_unsafe(lock_rwlock_ptr, ulong, 0400); >> +MODULE_PARM_DESC(lock_rwlock_ptr, "lock rwlock at address"); >> + >> +static unsigned int alloc_pages_nr; >> +module_param_unsafe(alloc_pages_nr, uint, 0600); >> +MODULE_PARM_DESC(alloc_pages_nr, "allocate and free pages under locks"); >> + >> +static unsigned int alloc_pages_order; >> +module_param(alloc_pages_order, uint, 0400); >> +MODULE_PARM_DESC(alloc_pages_order, "page order to allocate"); >> + >> +static gfp_t alloc_pages_gfp = GFP_KERNEL; >> +module_param_unsafe(alloc_pages_gfp, uint, 0400); >> +MODULE_PARM_DESC(alloc_pages_gfp, "allocate pages with this gfp_mask, default GFP_KERNEL"); >> + >> +static bool alloc_pages_atomic; >> +module_param(alloc_pages_atomic, bool, 0400); >> +MODULE_PARM_DESC(alloc_pages_atomic, "allocate pages with GFP_ATOMIC"); >> + >> +static bool reallocate_pages; >> +module_param(reallocate_pages, bool, 0400); >> +MODULE_PARM_DESC(reallocate_pages, "free and allocate pages between iterations"); >> + >> +static atomic_t alloc_pages_failed = ATOMIC_INIT(0); >> + >> +static atomic64_t max_lock_wait = ATOMIC64_INIT(0); >> + >> +static struct task_struct *main_task; >> +static int master_cpu; >> + >> +static void test_lock(bool master, bool verbose) >> +{ >> + u64 uninitialized_var(wait_start); >> + >> + if (measure_lock_wait) >> + wait_start = local_clock(); >> + >> + if (lock_mutex_ptr && master) { >> + if (verbose) >> + pr_notice("lock mutex %ps\n", (void *)lock_mutex_ptr); >> + mutex_lock((struct mutex *)lock_mutex_ptr); >> + } >> + >> + if (lock_rwsem_ptr && master) { >> + if (verbose) >> + pr_notice("lock rw_semaphore %ps\n", >> + (void *)lock_rwsem_ptr); >> + if (lock_read) >> + down_read((struct rw_semaphore *)lock_rwsem_ptr); >> + else >> + down_write((struct rw_semaphore *)lock_rwsem_ptr); >> + } >> + >> + if (lock_mmap_sem && master) { >> + if (verbose) >> + pr_notice("lock mmap_sem pid=%d\n", main_task->pid); >> + if (lock_read) >> + down_read(&main_task->mm->mmap_sem); >> + else >> + down_write(&main_task->mm->mmap_sem); >> + } >> + >> + if (disable_irq) >> + local_irq_disable(); >> + >> + if (disable_softirq) >> + local_bh_disable(); >> + >> + if (disable_preempt) >> + preempt_disable(); >> + >> + if (lock_rcu) >> + rcu_read_lock(); >> + >> + if (lock_spinlock_ptr && master) { >> + if (verbose) >> + pr_notice("lock spinlock %ps\n", >> + (void *)lock_spinlock_ptr); >> + spin_lock((spinlock_t *)lock_spinlock_ptr); >> + } >> + >> + if (lock_rwlock_ptr && master) { >> + if (verbose) >> + pr_notice("lock rwlock %ps\n", >> + (void *)lock_rwlock_ptr); >> + if (lock_read) >> + read_lock((rwlock_t *)lock_rwlock_ptr); >> + else >> + write_lock((rwlock_t *)lock_rwlock_ptr); >> + } >> + >> + if (measure_lock_wait) { >> + s64 cur_wait = local_clock() - wait_start; >> + s64 max_wait = atomic64_read(&max_lock_wait); >> + >> + do { >> + if (cur_wait < max_wait) >> + break; >> + max_wait = atomic64_cmpxchg(&max_lock_wait, >> + max_wait, cur_wait); >> + } while (max_wait != cur_wait); >> + >> + if (cur_wait > lock_wait_threshold) >> + pr_notice_ratelimited("lock wait %lld ns\n", cur_wait); >> + } >> +} >> + >> +static void test_unlock(bool master, bool verbose) >> +{ >> + if (lock_rwlock_ptr && master) { >> + if (lock_read) >> + read_unlock((rwlock_t *)lock_rwlock_ptr); >> + else >> + write_unlock((rwlock_t *)lock_rwlock_ptr); >> + if (verbose) >> + pr_notice("unlock rwlock %ps\n", >> + (void *)lock_rwlock_ptr); >> + } >> + >> + if (lock_spinlock_ptr && master) { >> + spin_unlock((spinlock_t *)lock_spinlock_ptr); >> + if (verbose) >> + pr_notice("unlock spinlock %ps\n", >> + (void *)lock_spinlock_ptr); >> + } >> + >> + if (lock_rcu) >> + rcu_read_unlock(); >> + >> + if (disable_preempt) >> + preempt_enable(); >> + >> + if (disable_softirq) >> + local_bh_enable(); >> + >> + if (disable_irq) >> + local_irq_enable(); >> + >> + if (lock_mmap_sem && master) { >> + if (lock_read) >> + up_read(&main_task->mm->mmap_sem); >> + else >> + up_write(&main_task->mm->mmap_sem); >> + if (verbose) >> + pr_notice("unlock mmap_sem pid=%d\n", main_task->pid); >> + } >> + >> + if (lock_rwsem_ptr && master) { >> + if (lock_read) >> + up_read((struct rw_semaphore *)lock_rwsem_ptr); >> + else >> + up_write((struct rw_semaphore *)lock_rwsem_ptr); >> + if (verbose) >> + pr_notice("unlock rw_semaphore %ps\n", >> + (void *)lock_rwsem_ptr); >> + } >> + >> + if (lock_mutex_ptr && master) { >> + mutex_unlock((struct mutex *)lock_mutex_ptr); >> + if (verbose) >> + pr_notice("unlock mutex %ps\n", >> + (void *)lock_mutex_ptr); >> + } >> +} >> + >> +static void test_alloc_pages(struct list_head *pages) >> +{ >> + struct page *page; >> + unsigned int i; >> + >> + for (i = 0; i < alloc_pages_nr; i++) { >> + page = alloc_pages(alloc_pages_gfp, alloc_pages_order); >> + if (!page) { >> + atomic_inc(&alloc_pages_failed); >> + break; >> + } >> + list_add(&page->lru, pages); >> + } >> +} >> + >> +static void test_free_pages(struct list_head *pages) >> +{ >> + struct page *page, *next; >> + >> + list_for_each_entry_safe(page, next, pages, lru) >> + __free_pages(page, alloc_pages_order); >> + INIT_LIST_HEAD(pages); >> +} >> + >> +static void test_wait(unsigned int secs, unsigned int nsecs) >> +{ >> + if (wait_state == TASK_RUNNING) { >> + if (secs) >> + mdelay(secs * MSEC_PER_SEC); >> + if (nsecs) >> + ndelay(nsecs); >> + return; >> + } >> + >> + __set_current_state(wait_state); >> + if (use_hrtimer) { >> + ktime_t time; >> + >> + time = ns_to_ktime((u64)secs * NSEC_PER_SEC + nsecs); >> + schedule_hrtimeout(&time, HRTIMER_MODE_REL); >> + } else { >> + schedule_timeout(secs * HZ + nsecs_to_jiffies(nsecs)); >> + } >> +} >> + >> +static void test_lockup(bool master) >> +{ >> + u64 lockup_start = local_clock(); >> + unsigned int iter = 0; >> + LIST_HEAD(pages); >> + >> + pr_notice("Start on CPU%d\n", raw_smp_processor_id()); >> + >> + test_lock(master, true); >> + >> + test_alloc_pages(&pages); >> + >> + while (iter++ < iterations && !signal_pending(main_task)) { >> + >> + if (iowait) >> + current->in_iowait = 1; >> + >> + test_wait(time_secs, time_nsecs); >> + >> + if (iowait) >> + current->in_iowait = 0; >> + >> + if (reallocate_pages) >> + test_free_pages(&pages); >> + >> + if (reacquire_locks) >> + test_unlock(master, false); >> + >> + if (touch_softlockup) >> + touch_softlockup_watchdog(); >> + >> + if (touch_hardlockup) >> + touch_nmi_watchdog(); >> + >> + if (call_cond_resched) >> + cond_resched(); >> + >> + test_wait(cooldown_secs, cooldown_nsecs); >> + >> + if (reacquire_locks) >> + test_lock(master, false); >> + >> + if (reallocate_pages) >> + test_alloc_pages(&pages); >> + } >> + >> + pr_notice("Finish on CPU%d in %lld ns\n", raw_smp_processor_id(), >> + local_clock() - lockup_start); >> + >> + test_free_pages(&pages); >> + >> + test_unlock(master, true); >> +} >> + >> +DEFINE_PER_CPU(struct work_struct, test_works); >> + >> +static void test_work_fn(struct work_struct *work) >> +{ >> + test_lockup(!lock_single || >> + work == per_cpu_ptr(&test_works, master_cpu)); >> +} >> + >> +static bool test_kernel_ptr(unsigned long addr, int size) >> +{ >> + void *ptr = (void *)addr; >> + char buf; >> + >> + if (!addr) >> + return false; >> + >> + /* should be at least readable kernel address */ >> + if (access_ok(ptr, 1) || >> + access_ok(ptr + size - 1, 1) || >> + probe_kernel_address(ptr, buf) || >> + probe_kernel_address(ptr + size - 1, buf)) { >> + pr_err("invalid kernel ptr: %#lx\n", addr); >> + return true; >> + } >> + >> + return false; >> +} >> + >> +static bool __maybe_unused test_magic(unsigned long addr, int offset, >> + unsigned int expected) >> +{ >> + void *ptr = (void *)addr + offset; >> + unsigned int magic = 0; >> + >> + if (!addr) >> + return false; >> + >> + if (probe_kernel_address(ptr, magic) || magic != expected) { >> + pr_err("invalid magic at %#lx + %#x = %#x, expected %#x\n", >> + addr, offset, magic, expected); >> + return true; >> + } >> + >> + return false; >> +} >> + >> +static int __init test_lockup_init(void) >> +{ >> + u64 test_start = local_clock(); >> + >> + main_task = current; >> + >> + switch (state[0]) { >> + case 'S': >> + wait_state = TASK_INTERRUPTIBLE; >> + break; >> + case 'D': >> + wait_state = TASK_UNINTERRUPTIBLE; >> + break; >> + case 'K': >> + wait_state = TASK_KILLABLE; >> + break; >> + case 'R': >> + wait_state = TASK_RUNNING; >> + break; >> + default: >> + pr_err("unknown state=%s\n", state); >> + return -EINVAL; >> + } >> + >> + if (alloc_pages_atomic) >> + alloc_pages_gfp = GFP_ATOMIC; >> + >> + if (test_kernel_ptr(lock_spinlock_ptr, sizeof(spinlock_t)) || >> + test_kernel_ptr(lock_rwlock_ptr, sizeof(rwlock_t)) || >> + test_kernel_ptr(lock_mutex_ptr, sizeof(struct mutex)) || >> + test_kernel_ptr(lock_rwsem_ptr, sizeof(struct rw_semaphore))) >> + return -EINVAL; >> + >> +#ifdef CONFIG_DEBUG_SPINLOCK >> + if (test_magic(lock_spinlock_ptr, >> + offsetof(spinlock_t, rlock.magic), >> + SPINLOCK_MAGIC) || >> + test_magic(lock_rwlock_ptr, >> + offsetof(rwlock_t, magic), >> + RWLOCK_MAGIC) || >> + test_magic(lock_mutex_ptr, >> + offsetof(struct mutex, wait_lock.rlock.magic), >> + SPINLOCK_MAGIC) || >> + test_magic(lock_rwsem_ptr, >> + offsetof(struct rw_semaphore, wait_lock.magic), >> + SPINLOCK_MAGIC)) >> + return -EINVAL; >> +#endif >> + >> + if ((wait_state != TASK_RUNNING || >> + (call_cond_resched && !reacquire_locks) || >> + (alloc_pages_nr && gfpflags_allow_blocking(alloc_pages_gfp))) && >> + (disable_irq || disable_softirq || disable_preempt || lock_rcu || >> + lock_spinlock_ptr || lock_rwlock_ptr)) { >> + pr_err("refuse to sleep in atomic context\n"); >> + return -EINVAL; >> + } >> + >> + if (lock_mmap_sem && !main_task->mm) { >> + pr_err("no mm to lock mmap_sem\n"); >> + return -EINVAL; >> + } >> + >> + pr_notice("START pid=%d time=%u +%u ns cooldown=%u +%u ns iteraions=%u state=%s %s%s%s%s%s%s%s%s%s%s%s\n", >> + main_task->pid, time_secs, time_nsecs, >> + cooldown_secs, cooldown_nsecs, iterations, state, >> + all_cpus ? "all_cpus " : "", >> + iowait ? "iowait " : "", >> + disable_irq ? "disable_irq " : "", >> + disable_softirq ? "disable_softirq " : "", >> + disable_preempt ? "disable_preempt " : "", >> + lock_rcu ? "lock_rcu " : "", >> + lock_read ? "lock_read " : "", >> + touch_softlockup ? "touch_softlockup " : "", >> + touch_hardlockup ? "touch_hardlockup " : "", >> + call_cond_resched ? "call_cond_resched " : "", >> + reacquire_locks ? "reacquire_locks " : ""); >> + >> + if (alloc_pages_nr) >> + pr_notice("ALLOCATE PAGES nr=%u order=%u gfp=%pGg %s\n", >> + alloc_pages_nr, alloc_pages_order, &alloc_pages_gfp, >> + reallocate_pages ? "reallocate_pages " : ""); >> + >> + if (all_cpus) { >> + unsigned int cpu; >> + >> + cpus_read_lock(); >> + >> + preempt_disable(); >> + master_cpu = smp_processor_id(); >> + for_each_online_cpu(cpu) { >> + INIT_WORK(per_cpu_ptr(&test_works, cpu), test_work_fn); >> + queue_work_on(cpu, system_highpri_wq, >> + per_cpu_ptr(&test_works, cpu)); >> + } >> + preempt_enable(); >> + >> + for_each_online_cpu(cpu) >> + flush_work(per_cpu_ptr(&test_works, cpu)); >> + >> + cpus_read_unlock(); >> + } else { >> + test_lockup(true); >> + } >> + >> + if (measure_lock_wait) >> + pr_notice("Maximum lock wait: %lld ns\n", >> + atomic64_read(&max_lock_wait)); >> + >> + if (alloc_pages_nr) >> + pr_notice("Page allocation failed %u times\n", >> + atomic_read(&alloc_pages_failed)); >> + >> + pr_notice("FINISH in %llu ns\n", local_clock() - test_start); >> + >> + if (signal_pending(main_task)) >> + return -EINTR; >> + >> + return -EAGAIN; >> +} >> +module_init(test_lockup_init); >> + >> +MODULE_LICENSE("GPL"); >> +MODULE_AUTHOR("Konstantin Khlebnikov "); >> +MODULE_DESCRIPTION("Test module to generate lockups"); >> >