Messages in this thread | | | Date | Mon, 10 Feb 2020 17:26:23 -0800 | From | Kees Cook <> | Subject | Re: [PATCH] lib/test_lockup: test module to generate lockups |
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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 ?
-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=$CGROUP_MUTEX reacquire_locks measure_lock_wait > > Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> > --- > lib/Kconfig.debug | 12 + > lib/Makefile | 1 > lib/test_lockup.c | 554 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 567 insertions(+) > create mode 100644 lib/test_lockup.c > > diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug > index 69def4a9df00..8feaf71dab15 100644 > --- a/lib/Kconfig.debug > +++ b/lib/Kconfig.debug > @@ -978,6 +978,18 @@ config WQ_WATCHDOG > state. This can be configured through kernel parameter > "workqueue.watchdog_thresh" and its sysfs counterpart. > > +config TEST_LOCKUP > + tristate "Test module to generate lockups" > + help > + This builds the "test_lockup" module that helps to make sure > + that watchdogs and lockup detectors are working properly. > + > + Depending on module parameters it could emulate soft or hard > + lockup, "hung task", or locking arbitrary lock for a long time. > + Also it could generate series of lockups with cooling-down periods. > + > + If unsure, say N. > + > endmenu # "Debug lockups and hangs" > > menu "Scheduler Debugging" > diff --git a/lib/Makefile b/lib/Makefile > index 5d64890d6b6a..b5372a83ebe2 100644 > --- a/lib/Makefile > +++ b/lib/Makefile > @@ -89,6 +89,7 @@ obj-$(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 <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/delay.h> > +#include <linux/sched.h> > +#include <linux/sched/signal.h> > +#include <linux/sched/clock.h> > +#include <linux/cpu.h> > +#include <linux/nmi.h> > +#include <linux/mm.h> > +#include <linux/uaccess.h> > + > +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 <khlebnikov@yandex-team.ru>"); > +MODULE_DESCRIPTION("Test module to generate lockups"); >
-- Kees Cook
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