From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- tools/virtio/virtio_test.c | 403 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 403 insertions(+) create mode 100644 tools/virtio/virtio_test.c (limited to 'tools/virtio/virtio_test.c') diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c new file mode 100644 index 000000000..028f54e68 --- /dev/null +++ b/tools/virtio/virtio_test.c @@ -0,0 +1,403 @@ +// SPDX-License-Identifier: GPL-2.0 +#define _GNU_SOURCE +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "../../drivers/vhost/test.h" + +#define RANDOM_BATCH -1 + +/* Unused */ +void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end; + +struct vq_info { + int kick; + int call; + int num; + int idx; + void *ring; + /* copy used for control */ + struct vring vring; + struct virtqueue *vq; +}; + +struct vdev_info { + struct virtio_device vdev; + int control; + struct pollfd fds[1]; + struct vq_info vqs[1]; + int nvqs; + void *buf; + size_t buf_size; + struct vhost_memory *mem; +}; + +static const struct vhost_vring_file no_backend = { .fd = -1 }, + backend = { .fd = 1 }; +static const struct vhost_vring_state null_state = {}; + +bool vq_notify(struct virtqueue *vq) +{ + struct vq_info *info = vq->priv; + unsigned long long v = 1; + int r; + r = write(info->kick, &v, sizeof v); + assert(r == sizeof v); + return true; +} + +void vq_callback(struct virtqueue *vq) +{ +} + + +void vhost_vq_setup(struct vdev_info *dev, struct vq_info *info) +{ + struct vhost_vring_state state = { .index = info->idx }; + struct vhost_vring_file file = { .index = info->idx }; + unsigned long long features = dev->vdev.features; + struct vhost_vring_addr addr = { + .index = info->idx, + .desc_user_addr = (uint64_t)(unsigned long)info->vring.desc, + .avail_user_addr = (uint64_t)(unsigned long)info->vring.avail, + .used_user_addr = (uint64_t)(unsigned long)info->vring.used, + }; + int r; + r = ioctl(dev->control, VHOST_SET_FEATURES, &features); + assert(r >= 0); + state.num = info->vring.num; + r = ioctl(dev->control, VHOST_SET_VRING_NUM, &state); + assert(r >= 0); + state.num = 0; + r = ioctl(dev->control, VHOST_SET_VRING_BASE, &state); + assert(r >= 0); + r = ioctl(dev->control, VHOST_SET_VRING_ADDR, &addr); + assert(r >= 0); + file.fd = info->kick; + r = ioctl(dev->control, VHOST_SET_VRING_KICK, &file); + assert(r >= 0); + file.fd = info->call; + r = ioctl(dev->control, VHOST_SET_VRING_CALL, &file); + assert(r >= 0); +} + +static void vq_reset(struct vq_info *info, int num, struct virtio_device *vdev) +{ + if (info->vq) + vring_del_virtqueue(info->vq); + + memset(info->ring, 0, vring_size(num, 4096)); + vring_init(&info->vring, num, info->ring, 4096); + info->vq = vring_new_virtqueue(info->idx, num, 4096, vdev, true, false, + info->ring, vq_notify, vq_callback, "test"); + assert(info->vq); + info->vq->priv = info; +} + +static void vq_info_add(struct vdev_info *dev, int num) +{ + struct vq_info *info = &dev->vqs[dev->nvqs]; + int r; + info->idx = dev->nvqs; + info->kick = eventfd(0, EFD_NONBLOCK); + info->call = eventfd(0, EFD_NONBLOCK); + r = posix_memalign(&info->ring, 4096, vring_size(num, 4096)); + assert(r >= 0); + vq_reset(info, num, &dev->vdev); + vhost_vq_setup(dev, info); + dev->fds[info->idx].fd = info->call; + dev->fds[info->idx].events = POLLIN; + dev->nvqs++; +} + +static void vdev_info_init(struct vdev_info* dev, unsigned long long features) +{ + int r; + memset(dev, 0, sizeof *dev); + dev->vdev.features = features; + INIT_LIST_HEAD(&dev->vdev.vqs); + spin_lock_init(&dev->vdev.vqs_list_lock); + dev->buf_size = 1024; + dev->buf = malloc(dev->buf_size); + assert(dev->buf); + dev->control = open("/dev/vhost-test", O_RDWR); + assert(dev->control >= 0); + r = ioctl(dev->control, VHOST_SET_OWNER, NULL); + assert(r >= 0); + dev->mem = malloc(offsetof(struct vhost_memory, regions) + + sizeof dev->mem->regions[0]); + assert(dev->mem); + memset(dev->mem, 0, offsetof(struct vhost_memory, regions) + + sizeof dev->mem->regions[0]); + dev->mem->nregions = 1; + dev->mem->regions[0].guest_phys_addr = (long)dev->buf; + dev->mem->regions[0].userspace_addr = (long)dev->buf; + dev->mem->regions[0].memory_size = dev->buf_size; + r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem); + assert(r >= 0); +} + +/* TODO: this is pretty bad: we get a cache line bounce + * for the wait queue on poll and another one on read, + * plus the read which is there just to clear the + * current state. */ +static void wait_for_interrupt(struct vdev_info *dev) +{ + int i; + unsigned long long val; + poll(dev->fds, dev->nvqs, -1); + for (i = 0; i < dev->nvqs; ++i) + if (dev->fds[i].revents & POLLIN) { + read(dev->fds[i].fd, &val, sizeof val); + } +} + +static void run_test(struct vdev_info *dev, struct vq_info *vq, + bool delayed, int batch, int reset_n, int bufs) +{ + struct scatterlist sl; + long started = 0, completed = 0, next_reset = reset_n; + long completed_before, started_before; + int r, test = 1; + unsigned int len; + long long spurious = 0; + const bool random_batch = batch == RANDOM_BATCH; + + r = ioctl(dev->control, VHOST_TEST_RUN, &test); + assert(r >= 0); + if (!reset_n) { + next_reset = INT_MAX; + } + + for (;;) { + virtqueue_disable_cb(vq->vq); + completed_before = completed; + started_before = started; + do { + const bool reset = completed > next_reset; + if (random_batch) + batch = (random() % vq->vring.num) + 1; + + while (started < bufs && + (started - completed) < batch) { + sg_init_one(&sl, dev->buf, dev->buf_size); + r = virtqueue_add_outbuf(vq->vq, &sl, 1, + dev->buf + started, + GFP_ATOMIC); + if (unlikely(r != 0)) { + if (r == -ENOSPC && + started > started_before) + r = 0; + else + r = -1; + break; + } + + ++started; + + if (unlikely(!virtqueue_kick(vq->vq))) { + r = -1; + break; + } + } + + if (started >= bufs) + r = -1; + + if (reset) { + r = ioctl(dev->control, VHOST_TEST_SET_BACKEND, + &no_backend); + assert(!r); + } + + /* Flush out completed bufs if any */ + while (virtqueue_get_buf(vq->vq, &len)) { + ++completed; + r = 0; + } + + if (reset) { + struct vhost_vring_state s = { .index = 0 }; + + vq_reset(vq, vq->vring.num, &dev->vdev); + + r = ioctl(dev->control, VHOST_GET_VRING_BASE, + &s); + assert(!r); + + s.num = 0; + r = ioctl(dev->control, VHOST_SET_VRING_BASE, + &null_state); + assert(!r); + + r = ioctl(dev->control, VHOST_TEST_SET_BACKEND, + &backend); + assert(!r); + + started = completed; + while (completed > next_reset) + next_reset += completed; + } + } while (r == 0); + if (completed == completed_before && started == started_before) + ++spurious; + assert(completed <= bufs); + assert(started <= bufs); + if (completed == bufs) + break; + if (delayed) { + if (virtqueue_enable_cb_delayed(vq->vq)) + wait_for_interrupt(dev); + } else { + if (virtqueue_enable_cb(vq->vq)) + wait_for_interrupt(dev); + } + } + test = 0; + r = ioctl(dev->control, VHOST_TEST_RUN, &test); + assert(r >= 0); + fprintf(stderr, + "spurious wakeups: 0x%llx started=0x%lx completed=0x%lx\n", + spurious, started, completed); +} + +const char optstring[] = "h"; +const struct option longopts[] = { + { + .name = "help", + .val = 'h', + }, + { + .name = "event-idx", + .val = 'E', + }, + { + .name = "no-event-idx", + .val = 'e', + }, + { + .name = "indirect", + .val = 'I', + }, + { + .name = "no-indirect", + .val = 'i', + }, + { + .name = "virtio-1", + .val = '1', + }, + { + .name = "no-virtio-1", + .val = '0', + }, + { + .name = "delayed-interrupt", + .val = 'D', + }, + { + .name = "no-delayed-interrupt", + .val = 'd', + }, + { + .name = "batch", + .val = 'b', + .has_arg = required_argument, + }, + { + .name = "reset", + .val = 'r', + .has_arg = optional_argument, + }, + { + } +}; + +static void help(int status) +{ + fprintf(stderr, "Usage: virtio_test [--help]" + " [--no-indirect]" + " [--no-event-idx]" + " [--no-virtio-1]" + " [--delayed-interrupt]" + " [--batch=random/N]" + " [--reset=N]" + "\n"); + + exit(status); +} + +int main(int argc, char **argv) +{ + struct vdev_info dev; + unsigned long long features = (1ULL << VIRTIO_RING_F_INDIRECT_DESC) | + (1ULL << VIRTIO_RING_F_EVENT_IDX) | (1ULL << VIRTIO_F_VERSION_1); + long batch = 1, reset = 0; + int o; + bool delayed = false; + + for (;;) { + o = getopt_long(argc, argv, optstring, longopts, NULL); + switch (o) { + case -1: + goto done; + case '?': + help(2); + case 'e': + features &= ~(1ULL << VIRTIO_RING_F_EVENT_IDX); + break; + case 'h': + help(0); + case 'i': + features &= ~(1ULL << VIRTIO_RING_F_INDIRECT_DESC); + break; + case '0': + features &= ~(1ULL << VIRTIO_F_VERSION_1); + break; + case 'D': + delayed = true; + break; + case 'b': + if (0 == strcmp(optarg, "random")) { + batch = RANDOM_BATCH; + } else { + batch = strtol(optarg, NULL, 10); + assert(batch > 0); + assert(batch < (long)INT_MAX + 1); + } + break; + case 'r': + if (!optarg) { + reset = 1; + } else { + reset = strtol(optarg, NULL, 10); + assert(reset > 0); + assert(reset < (long)INT_MAX + 1); + } + break; + default: + assert(0); + break; + } + } + +done: + vdev_info_init(&dev, features); + vq_info_add(&dev, 256); + run_test(&dev, &dev.vqs[0], delayed, batch, reset, 0x100000); + return 0; +} -- cgit v1.3.1