On Wed, Jul 13, 2022 at 11:17:18PM +0200, Daniel Bristot de Oliveira wrote:
> A runtime monitor can cause a reaction to the detection of an
> exception on the model's execution. By default, the monitors have
> tracing reactions, printing the monitor output via tracepoints.
> But other reactions can be added (on-demand) via this interface.
>
> The user interface resembles the kernel tracing interface and
> presents these files:
>
> "available_reactors"
> - Reading shows the available reactors, one per line.
>
> For example:
> # cat available_reactors
> nop
> panic
> printk
>
> "reacting_on"
> - It is an on/off general switch for reactors, disabling
> all reactions.
>
> "monitors/MONITOR/reactors"
> - List available reactors, with the select reaction for the given
> MONITOR inside []. The default one is the nop (no operation)
> reactor.
> - Writing the name of a reactor enables it to the given
> MONITOR.
>
> For example:
> # cat monitors/wip/reactors
> [nop]
> panic
> printk
> # echo panic > monitors/wip/reactors
> # cat monitors/wip/reactors
> nop
> [panic]
> printk
>
> Cc: Wim Van Sebroeck <wim@xxxxxxxxxxxxxxxxxx>
> Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> Cc: Jonathan Corbet <corbet@xxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Will Deacon <will@xxxxxxxxxx>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Marco Elver <elver@xxxxxxxxxx>
> Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> Cc: Shuah Khan <skhan@xxxxxxxxxxxxxxxxxxx>
> Cc: Gabriele Paoloni <gpaoloni@xxxxxxxxxx>
> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> Cc: Clark Williams <williams@xxxxxxxxxx>
> Cc: Tao Zhou <tao.zhou@xxxxxxxxx>
> Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
> Cc: linux-doc@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
> Cc: linux-trace-devel@xxxxxxxxxxxxxxx
> Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
> ---
> include/linux/rv.h | 11 +
> kernel/trace/rv/Kconfig | 11 +
> kernel/trace/rv/Makefile | 1 +
> kernel/trace/rv/rv.c | 9 +
> kernel/trace/rv/rv.h | 29 ++
> kernel/trace/rv/rv_reactors.c | 488 ++++++++++++++++++++++++++++++++++
> 6 files changed, 549 insertions(+)
> create mode 100644 kernel/trace/rv/rv_reactors.c
[snip]
> new file mode 100644
> index 000000000000..27f48fec5a51
> --- /dev/null
> +++ b/kernel/trace/rv/rv_reactors.c
> @@ -0,0 +1,488 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2019-2022 Red Hat, Inc. Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
> + *
> + * Runtime reactor interface.
> + *
> + * A runtime monitor can cause a reaction to the detection of an
> + * exception on the model's execution. By default, the monitors have
> + * tracing reactions, printing the monitor output via tracepoints.
> + * But other reactions can be added (on-demand) via this interface.
> + *
> + * == Registering reactors ==
> + *
> + * The struct rv_reactor defines a callback function to be executed
> + * in case of a model exception happens. The callback function
> + * receives a message to be (optionally) printed before executing
> + * the reaction.
> + *
> + * A RV reactor is registered via:
> + * int rv_register_reactor(struct rv_reactor *reactor)
> + * And unregistered via:
> + * int rv_unregister_reactor(struct rv_reactor *reactor)
> + *
> + * These functions are exported to modules, enabling reactors to be
> + * dynamically loaded.
> + *
> + * == User interface ==
> + *
> + * The user interface resembles the kernel tracing interface and
> + * presents these files:
> + *
> + * "available_reactors"
> + * - List the available reactors, one per line.
> + *
> + * For example:
> + * # cat available_reactors
> + * nop
> + * panic
> + * printk
> + *
> + * "reacting_on"
> + * - It is an on/off general switch for reactors, disabling
> + * all reactions.
> + *
> + * "monitors/MONITOR/reactors"
> + * - List available reactors, with the select reaction for the given
> + * MONITOR inside []. The default one is the nop (no operation)
> + * reactor.
> + * - Writing the name of an reactor enables it to the given
> + * MONITOR.
> + *
> + * For example:
> + * # cat monitors/wip/reactors
> + * [nop]
> + * panic
> + * printk
> + * # echo panic > monitors/wip/reactors
> + * # cat monitors/wip/reactors
> + * nop
> + * [panic]
> + * printk
> + */
> +
> +#include <linux/slab.h>
> +
> +#include "rv.h"
> +
> +bool __read_mostly reacting_on;
> +
> +/*
> + * Interface for the reactor register.
> + */
> +LIST_HEAD(rv_reactors_list);
> +
> +static struct rv_reactor_def *get_reactor_rdef_by_name(char *name)
> +{
> + struct rv_reactor_def *r;
> +
> + list_for_each_entry(r, &rv_reactors_list, list) {
> + if (strcmp(name, r->reactor->name) == 0)
> + return r;
> + }
> + return NULL;
> +}
> +
> +/*
> + * Available reactors seq functions.
> + */
> +static int reactors_show(struct seq_file *m, void *p)
> +{
> + struct rv_reactor_def *rea_def = p;
> +
> + seq_printf(m, "%s\n", rea_def->reactor->name);
> + return 0;
> +}
> +
> +static void reactors_stop(struct seq_file *m, void *p)
> +{
> + mutex_unlock(&rv_interface_lock);
> +}
> +
> +static void *reactors_start(struct seq_file *m, loff_t *pos)
> +{
> + mutex_lock(&rv_interface_lock);
> + return seq_list_start(&rv_reactors_list, *pos);
> +}
> +
> +static void *reactors_next(struct seq_file *m, void *p, loff_t *pos)
> +{
> + return seq_list_next(p, &rv_reactors_list, pos);
> +}
> +
> +/*
> + * available reactors seq definition.
> + */
> +static const struct seq_operations available_reactors_seq_ops = {
> + .start = reactors_start,
> + .next = reactors_next,
> + .stop = reactors_stop,
> + .show = reactors_show
> +};
> +
> +/*
> + * available_reactors interface.
> + */
> +static int available_reactors_open(struct inode *inode, struct file *file)
> +{
> + return seq_open(file, &available_reactors_seq_ops);
> +};
> +
> +static const struct file_operations available_reactors_ops = {
> + .open = available_reactors_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release
> +};
> +
> +/*
> + * Monitor reactor file.
> + */
> +static int monitor_reactor_show(struct seq_file *m, void *p)
> +{
> + struct rv_monitor_def *mdef = m->private;
> + struct rv_reactor_def *rdef = p;
> +
> + if (mdef->rdef == rdef)
> + seq_printf(m, "[%s]\n", rdef->reactor->name);
> + else
> + seq_printf(m, "%s\n", rdef->reactor->name);
> + return 0;
> +}
> +
> +/*
> + * available reactors seq definition.
> + */
> +static const struct seq_operations monitor_reactors_seq_ops = {
> + .start = reactors_start,
> + .next = reactors_next,
> + .stop = reactors_stop,
> + .show = monitor_reactor_show
> +};
> +
> +static ssize_t
> +monitor_reactors_write(struct file *file, const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + char buff[MAX_RV_REACTOR_NAME_SIZE + 2];
> + struct rv_monitor_def *mdef;
> + struct rv_reactor_def *rdef;
> + struct seq_file *seq_f;
> + int retval = -EINVAL;
> + bool enabled;
> + char *ptr;
> + int len;
> +
> + if (count < 1 || count > MAX_RV_REACTOR_NAME_SIZE + 2)
> + return -EINVAL;
The same case as patch1. The up bound check need to be changed.
> +
> + memset(buff, 0, sizeof(buff));
> +
> + retval = simple_write_to_buffer(buff, sizeof(buff) - 1, ppos, user_buf,
> + count);
> + if (!retval)
> + return -EFAULT;
If simple_write_to_buffer() is error(return value < 0), no return here.
If the return value is 0, no write has happened. For this case, the code
want to return -EFAULT.
> +
> + ptr = strim(buff);
> +
> + len = strlen(ptr);
> + if (!len)
> + return count;
> +
> + /*
> + * See monitor_reactors_open()
> + */
> + seq_f = file->private_data;
> + mdef = seq_f->private;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + retval = -EINVAL;
> +
> + /*
> + * nop special case: disable reacting.
> + */
> + if (strcmp(ptr, "nop") == 0) {
> +
> + enabled = mdef->monitor->enabled;
> + if (enabled)
> + mdef->monitor->stop();
> +
> + mdef->rdef = get_reactor_rdef_by_name("nop");
> + mdef->reacting = false;
> + mdef->monitor->react = NULL;
> +
> + if (enabled) {
> + mdef->monitor->start();
> + mdef->monitor->enabled = 1;
> + }
> +
> + retval = count;
> + goto unlock;
> + }
> +
> + list_for_each_entry(rdef, &rv_reactors_list, list) {
> + if (strcmp(ptr, rdef->reactor->name) != 0)
> + continue;
> +
> + /*
> + * found!
> + */
> + enabled = mdef->monitor->enabled;
> + if (enabled)
> + mdef->monitor->stop();
> +
> + mdef->rdef = rdef;
> + mdef->reacting = true;
> + mdef->monitor->react = rdef->reactor->react;
> +
> + if (enabled) {
> + mdef->monitor->start();
> + mdef->monitor->enabled = 1;
> + }
> +
> + retval = count;
> + break;
> + }
> +
> +unlock:
> + mutex_unlock(&rv_interface_lock);
> +
> + return retval;
> +}
> +
> +/*
> + * available_reactors interface.
> + */
> +static int monitor_reactors_open(struct inode *inode, struct file *file)
> +{
> + /*
> + * create file "private" info is stored in the inode->i_private
> + */
> + struct rv_monitor_def *mdef = inode->i_private;
> + struct seq_file *seq_f;
> + int ret;
> +
> + ret = seq_open(file, &monitor_reactors_seq_ops);
> + if (ret < 0)
> + return ret;
> +
> + /*
> + * seq_open stores the seq_file on the file->private data.
> + */
> + seq_f = file->private_data;
> +
> + /*
> + * Copy the create file "private" data to the seq_file
> + * private data.
> + */
> + seq_f->private = mdef;
> +
> + return 0;
> +};
> +
> +static const struct file_operations monitor_reactors_ops = {
> + .open = monitor_reactors_open,
> + .read = seq_read,
> + .llseek = seq_lseek,
> + .release = seq_release,
> + .write = monitor_reactors_write
> +};
> +
> +static int __rv_register_reactor(struct rv_reactor *reactor)
> +{
> + struct rv_reactor_def *r;
> +
> + list_for_each_entry(r, &rv_reactors_list, list) {
> + if (strcmp(reactor->name, r->reactor->name) == 0) {
> + pr_info("Reactor %s is already registered\n",
> + reactor->name);
> + return -EINVAL;
> + }
> + }
> +
> + r = kzalloc(sizeof(struct rv_reactor_def), GFP_KERNEL);
> + if (!r)
> + return -ENOMEM;
> +
> + r->reactor = reactor;
> + r->counter = 0;
> +
> + list_add_tail(&r->list, &rv_reactors_list);
> +
> + return 0;
> +}
> +
> +/**
> + * rv_register_reactor - register a rv reactor.
> + * @reactor: The rv_reactor to be registered.
> + *
> + * Returns 0 if successful, error otherwise.
> + */
> +int rv_register_reactor(struct rv_reactor *reactor)
> +{
> + int retval = 0;
> +
> + if (strlen(reactor->name) >= MAX_RV_REACTOR_NAME_SIZE) {
> + pr_info("Reactor %s has a name longer than %d\n",
> + reactor->name, MAX_RV_MONITOR_NAME_SIZE);
> + return -EINVAL;
> + }
> +
> + mutex_lock(&rv_interface_lock);
> + retval = __rv_register_reactor(reactor);
> + mutex_unlock(&rv_interface_lock);
> + return retval;
> +}
> +
> +/**
> + * rv_unregister_reactor - unregister a rv reactor.
> + * @reactor: The rv_reactor to be unregistered.
> + *
> + * Returns 0 if successful, error otherwise.
> + */
> +int rv_unregister_reactor(struct rv_reactor *reactor)
> +{
> + struct rv_reactor_def *ptr, *next;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + list_for_each_entry_safe(ptr, next, &rv_reactors_list, list) {
> + if (strcmp(reactor->name, ptr->reactor->name) == 0) {
> +
> + if (!ptr->counter) {
> + list_del(&ptr->list);
> + } else {
> + printk(KERN_WARNING
> + "rv: the rv_reactor %s is in use by %d monitor(s)\n",
> + ptr->reactor->name, ptr->counter);
> + printk(KERN_WARNING "rv: the rv_reactor %s cannot be removed\n",
> + ptr->reactor->name);
> + return -EBUSY;
> + }
> +
> + }
> + }
> +
> + mutex_unlock(&rv_interface_lock);
> + return 0;
> +}
> +
> +/*
> + * reacting_on interface.
> + */
> +static ssize_t reacting_on_read_data(struct file *filp,
> + char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + char *buff;
> +
> + mutex_lock(&rv_interface_lock);
> + buff = reacting_on ? "1\n" : "0\n";
> + mutex_unlock(&rv_interface_lock);
> +
> + return simple_read_from_buffer(user_buf, count, ppos, buff, strlen(buff)+1);
> +}
> +
> +static void turn_reacting_off(void)
> +{
> + reacting_on = false;
> +}
> +
> +static void turn_reacting_on(void)
> +{
> + reacting_on = true;
> +}
> +
> +static ssize_t
> +reacting_on_write_data(struct file *filp, const char __user *user_buf,
> + size_t count, loff_t *ppos)
> +{
> + int retval;
> + bool val;
> +
> + retval = kstrtobool_from_user(user_buf, count, &val);
> + if (retval)
> + return retval;
> +
> + mutex_lock(&rv_interface_lock);
> +
> + if (val)
> + turn_reacting_on();
> + else
> + turn_reacting_off();
> +
> + mutex_unlock(&rv_interface_lock);
> +
> + return count;
> +}
> +
> +static const struct file_operations reacting_on_fops = {
> + .open = simple_open,
> + .llseek = no_llseek,
> + .write = reacting_on_write_data,
> + .read = reacting_on_read_data,
> +};
> +
> +int reactor_create_monitor_files(struct rv_monitor_def *mdef)
> +{
> + struct dentry *tmp;
> +
> + tmp = rv_create_file("reactors", RV_MODE_WRITE, mdef->root_d, mdef, &monitor_reactors_ops);
> + if (!tmp)
> + return -ENOMEM;
> +
> + /*
> + * Configure as the rv_nop reactor.
> + */
> + mdef->rdef = get_reactor_rdef_by_name("nop");
> + mdef->reacting = false;
Not need `mdef->monitor->react = NULL;`. The monitor->react is
not set to others that means it is set to NULL, When initializing
the specific rv_monitor structure. Note to myself. Thanks.
> +
> + return 0;
> +}
> +
> +/*
> + * None reactor register
> + */
> +static void rv_nop_reaction(char *msg)
> +{
> +}
> +
> +struct rv_reactor rv_nop = {
> + .name = "nop",
> + .description = "no-operation reactor: do nothing.",
> + .react = rv_nop_reaction
> +};
> +
> +/*
> + * This section collects the rv/ root dir files and folders.
> + */
> +int init_rv_reactors(struct dentry *root_dir)
> +{
> + struct dentry *available, *reacting;
> + int retval;
> +
> + available = rv_create_file("available_reactors", RV_MODE_READ, root_dir, NULL,
> + &available_reactors_ops);
> + if (!available)
> + goto out_err;
> +
> + reacting = rv_create_file("reacting_on", RV_MODE_WRITE, root_dir, NULL, &reacting_on_fops);
> + if (!reacting)
> + goto rm_available;
> +
> + retval = __rv_register_reactor(&rv_nop);
> + if (retval)
> + goto rm_reacting;
> +
> + reacting_on = 1;
> +
> + return 0;
> +
> +rm_reacting:
> + rv_remove(reacting);
> +rm_available:
> + rv_remove(available);
> +out_err:
> + return -ENOMEM;
> +}
> --
> 2.35.1
|