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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-23 13:28:57 -0700
commit4352b8aee98005853aa63f57d6377282de17a33f (patch)
tree27614d7a9ef05c32d089004e104364ce42324837 /lib/fault-inject.c
downloadlinux-stable-4352b8aee98005853aa63f57d6377282de17a33f.tar.gz
linux-stable-4352b8aee98005853aa63f57d6377282de17a33f.zip
Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted
Pull I3C updates from Alexandre Belloni: "A new driver this cycle, for the AMD AXI I3C controller. There are also new features such as IBI wakeup support, SETAASA device discovery and ACPI support for the the DAA methods, meaning we can now communicate with the SPD devices on DDR5 modules. New driver: - AMD AXI I3C master controller Subsystem: - I3C Common Command Code (CCC) handling improvements, especially around GET CCCs - SETAASA device discovery support - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as well as I2C devices on I3C bus - IBI-based wakeup support Drivers: - dw: SETAASA support - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C controller support, PIO queue management support for HCI v1.2 - renesas: improve suspend to RAM support, add runtime PM support" * tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits) i3c: dw: reduce do_daa time if there's no client i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2 i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode i3c: dw: rename "pclk" to "apb" to match dt-binding i3c: dw: make struct dw_i3c_cmd smaller i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding i3c: renesas: Don't register devices when ENTDAA times out i3c: master: dw-i3c-master: fix OD timing for first broadcast i3c: mipi-i3c-hci: Advertise IBI wakeup capability i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev() i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI i3c: master: Reject IBI requests from non-IBI-capable devices i3c: master: Add helper to query bus wakeup requirements i3c: master: Report wakeup events for IBIs i3c: master: Support IBI-based wakeup capability i3c: master: Fix potential UAF in i3c_device_match() i3c: master: Fix potential UAF in i3c_device_uevent() i3c: Make dev->desc locking assumptions explicit i3c: master: Fix use-after-free of master->this ...
Diffstat (limited to 'lib/fault-inject.c')
-rw-r--r--lib/fault-inject.c462
1 files changed, 462 insertions, 0 deletions
diff --git a/lib/fault-inject.c b/lib/fault-inject.c
new file mode 100644
index 000000000..999053fa1
--- /dev/null
+++ b/lib/fault-inject.c
@@ -0,0 +1,462 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/prandom.h>
+#include <linux/debugfs.h>
+#include <linux/sched.h>
+#include <linux/stat.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/export.h>
+#include <linux/interrupt.h>
+#include <linux/stacktrace.h>
+#include <linux/fault-inject.h>
+
+/*
+ * The should_fail() functions use prandom instead of the normal Linux RNG
+ * since they don't need cryptographically secure random numbers.
+ */
+static DEFINE_PER_CPU(struct rnd_state, fault_rnd_state);
+
+static u32 fault_prandom_u32_below_100(void)
+{
+ struct rnd_state *state;
+ u32 res;
+
+ state = &get_cpu_var(fault_rnd_state);
+ res = prandom_u32_state(state);
+ put_cpu_var(fault_rnd_state);
+
+ return res % 100;
+}
+
+/*
+ * setup_fault_attr() is a helper function for various __setup handlers, so it
+ * returns 0 on error, because that is what __setup handlers do.
+ */
+int setup_fault_attr(struct fault_attr *attr, char *str)
+{
+ unsigned long probability;
+ unsigned long interval;
+ int times;
+ int space;
+
+ /* "<interval>,<probability>,<space>,<times>" */
+ if (sscanf(str, "%lu,%lu,%d,%d",
+ &interval, &probability, &space, &times) < 4) {
+ printk(KERN_WARNING
+ "FAULT_INJECTION: failed to parse arguments\n");
+ return 0;
+ }
+
+ prandom_init_once(&fault_rnd_state);
+
+ attr->probability = probability;
+ attr->interval = interval;
+ atomic_set(&attr->times, times);
+ atomic_set(&attr->space, space);
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(setup_fault_attr);
+
+static void fail_dump(struct fault_attr *attr)
+{
+ if (attr->verbose > 0 && __ratelimit(&attr->ratelimit_state)) {
+ printk(KERN_NOTICE "FAULT_INJECTION: forcing a failure.\n"
+ "name %pd, interval %lu, probability %lu, "
+ "space %d, times %d\n", attr->dname,
+ attr->interval, attr->probability,
+ atomic_read(&attr->space),
+ atomic_read(&attr->times));
+ if (attr->verbose > 1)
+ dump_stack();
+ }
+}
+
+#define atomic_dec_not_zero(v) atomic_add_unless((v), -1, 0)
+
+static bool fail_task(struct fault_attr *attr, struct task_struct *task)
+{
+ return in_task() && task->make_it_fail;
+}
+
+#define MAX_STACK_TRACE_DEPTH 32
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+static bool fail_stacktrace(struct fault_attr *attr)
+{
+ int depth = attr->stacktrace_depth;
+ unsigned long entries[MAX_STACK_TRACE_DEPTH];
+ int n, nr_entries;
+ bool found = (attr->require_start == 0 && attr->require_end == ULONG_MAX);
+
+ if (depth == 0 || (found && !attr->reject_start && !attr->reject_end))
+ return found;
+
+ nr_entries = stack_trace_save(entries, depth, 1);
+ for (n = 0; n < nr_entries; n++) {
+ if (attr->reject_start <= entries[n] &&
+ entries[n] < attr->reject_end)
+ return false;
+ if (attr->require_start <= entries[n] &&
+ entries[n] < attr->require_end)
+ found = true;
+ }
+ return found;
+}
+
+#else
+
+static inline bool fail_stacktrace(struct fault_attr *attr)
+{
+ return true;
+}
+
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
+/*
+ * This code is stolen from failmalloc-1.0
+ * http://www.nongnu.org/failmalloc/
+ */
+
+bool should_fail_ex(struct fault_attr *attr, ssize_t size, int flags)
+{
+ bool stack_checked = false;
+
+ if (in_task()) {
+ unsigned int fail_nth = READ_ONCE(current->fail_nth);
+
+ if (fail_nth) {
+ if (!fail_stacktrace(attr))
+ return false;
+
+ stack_checked = true;
+ fail_nth--;
+ WRITE_ONCE(current->fail_nth, fail_nth);
+ if (!fail_nth)
+ goto fail;
+
+ return false;
+ }
+ }
+
+ /* No need to check any other properties if the probability is 0 */
+ if (attr->probability == 0)
+ return false;
+
+ if (attr->task_filter && !fail_task(attr, current))
+ return false;
+
+ if (atomic_read(&attr->times) == 0)
+ return false;
+
+ if (!stack_checked && !fail_stacktrace(attr))
+ return false;
+
+ if (atomic_read(&attr->space) > size) {
+ atomic_sub(size, &attr->space);
+ return false;
+ }
+
+ if (attr->interval > 1) {
+ attr->count++;
+ if (attr->count % attr->interval)
+ return false;
+ }
+
+ if (attr->probability <= fault_prandom_u32_below_100())
+ return false;
+
+fail:
+ if (!(flags & FAULT_NOWARN))
+ fail_dump(attr);
+
+ if (atomic_read(&attr->times) != -1)
+ atomic_dec_not_zero(&attr->times);
+
+ return true;
+}
+
+bool should_fail(struct fault_attr *attr, ssize_t size)
+{
+ return should_fail_ex(attr, size, 0);
+}
+EXPORT_SYMBOL_GPL(should_fail);
+
+#ifdef CONFIG_FAULT_INJECTION_DEBUG_FS
+
+static int debugfs_ul_set(void *data, u64 val)
+{
+ *(unsigned long *)data = val;
+ return 0;
+}
+
+static int debugfs_ul_get(void *data, u64 *val)
+{
+ *val = *(unsigned long *)data;
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_ul, debugfs_ul_get, debugfs_ul_set, "%llu\n");
+
+static void debugfs_create_ul(const char *name, umode_t mode,
+ struct dentry *parent, unsigned long *value)
+{
+ debugfs_create_file(name, mode, parent, value, &fops_ul);
+}
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+static int debugfs_stacktrace_depth_set(void *data, u64 val)
+{
+ *(unsigned long *)data =
+ min_t(unsigned long, val, MAX_STACK_TRACE_DEPTH);
+
+ return 0;
+}
+
+DEFINE_SIMPLE_ATTRIBUTE(fops_stacktrace_depth, debugfs_ul_get,
+ debugfs_stacktrace_depth_set, "%llu\n");
+
+static void debugfs_create_stacktrace_depth(const char *name, umode_t mode,
+ struct dentry *parent,
+ unsigned long *value)
+{
+ debugfs_create_file(name, mode, parent, value, &fops_stacktrace_depth);
+}
+
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
+struct dentry *fault_create_debugfs_attr(const char *name,
+ struct dentry *parent, struct fault_attr *attr)
+{
+ umode_t mode = S_IFREG | S_IRUSR | S_IWUSR;
+ struct dentry *dir;
+
+ dir = debugfs_create_dir(name, parent);
+ if (IS_ERR(dir))
+ return dir;
+
+ prandom_init_once(&fault_rnd_state);
+
+ debugfs_create_ul("probability", mode, dir, &attr->probability);
+ debugfs_create_ul("interval", mode, dir, &attr->interval);
+ debugfs_create_atomic_t("times", mode, dir, &attr->times);
+ debugfs_create_atomic_t("space", mode, dir, &attr->space);
+ debugfs_create_ul("verbose", mode, dir, &attr->verbose);
+ debugfs_create_u32("verbose_ratelimit_interval_ms", mode, dir,
+ &attr->ratelimit_state.interval);
+ debugfs_create_u32("verbose_ratelimit_burst", mode, dir,
+ &attr->ratelimit_state.burst);
+ debugfs_create_bool("task-filter", mode, dir, &attr->task_filter);
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+ debugfs_create_stacktrace_depth("stacktrace-depth", mode, dir,
+ &attr->stacktrace_depth);
+ debugfs_create_xul("require-start", mode, dir, &attr->require_start);
+ debugfs_create_xul("require-end", mode, dir, &attr->require_end);
+ debugfs_create_xul("reject-start", mode, dir, &attr->reject_start);
+ debugfs_create_xul("reject-end", mode, dir, &attr->reject_end);
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
+ attr->dname = dget(dir);
+ return dir;
+}
+EXPORT_SYMBOL_GPL(fault_create_debugfs_attr);
+
+#endif /* CONFIG_FAULT_INJECTION_DEBUG_FS */
+
+#ifdef CONFIG_FAULT_INJECTION_CONFIGFS
+
+/* These configfs attribute utilities are copied from drivers/block/null_blk/main.c */
+
+static ssize_t fault_uint_attr_show(unsigned int val, char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%u\n", val);
+}
+
+static ssize_t fault_ulong_attr_show(unsigned long val, char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%lu\n", val);
+}
+
+static ssize_t fault_bool_attr_show(bool val, char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%u\n", val);
+}
+
+static ssize_t fault_atomic_t_attr_show(atomic_t val, char *page)
+{
+ return snprintf(page, PAGE_SIZE, "%d\n", atomic_read(&val));
+}
+
+static ssize_t fault_uint_attr_store(unsigned int *val, const char *page, size_t count)
+{
+ unsigned int tmp;
+ int result;
+
+ result = kstrtouint(page, 0, &tmp);
+ if (result < 0)
+ return result;
+
+ *val = tmp;
+ return count;
+}
+
+static ssize_t fault_ulong_attr_store(unsigned long *val, const char *page, size_t count)
+{
+ int result;
+ unsigned long tmp;
+
+ result = kstrtoul(page, 0, &tmp);
+ if (result < 0)
+ return result;
+
+ *val = tmp;
+ return count;
+}
+
+static ssize_t fault_bool_attr_store(bool *val, const char *page, size_t count)
+{
+ bool tmp;
+ int result;
+
+ result = kstrtobool(page, &tmp);
+ if (result < 0)
+ return result;
+
+ *val = tmp;
+ return count;
+}
+
+static ssize_t fault_atomic_t_attr_store(atomic_t *val, const char *page, size_t count)
+{
+ int tmp;
+ int result;
+
+ result = kstrtoint(page, 0, &tmp);
+ if (result < 0)
+ return result;
+
+ atomic_set(val, tmp);
+ return count;
+}
+
+#define CONFIGFS_ATTR_NAMED(_pfx, _name, _attr_name) \
+static struct configfs_attribute _pfx##attr_##_name = { \
+ .ca_name = _attr_name, \
+ .ca_mode = 0644, \
+ .ca_owner = THIS_MODULE, \
+ .show = _pfx##_name##_show, \
+ .store = _pfx##_name##_store, \
+}
+
+static struct fault_config *to_fault_config(struct config_item *item)
+{
+ return container_of(to_config_group(item), struct fault_config, group);
+}
+
+#define FAULT_CONFIGFS_ATTR_NAMED(NAME, ATTR_NAME, MEMBER, TYPE) \
+static ssize_t fault_##NAME##_show(struct config_item *item, char *page) \
+{ \
+ return fault_##TYPE##_attr_show(to_fault_config(item)->attr.MEMBER, page); \
+} \
+static ssize_t fault_##NAME##_store(struct config_item *item, const char *page, size_t count) \
+{ \
+ struct fault_config *config = to_fault_config(item); \
+ return fault_##TYPE##_attr_store(&config->attr.MEMBER, page, count); \
+} \
+CONFIGFS_ATTR_NAMED(fault_, NAME, ATTR_NAME)
+
+#define FAULT_CONFIGFS_ATTR(NAME, TYPE) \
+ FAULT_CONFIGFS_ATTR_NAMED(NAME, __stringify(NAME), NAME, TYPE)
+
+FAULT_CONFIGFS_ATTR(probability, ulong);
+FAULT_CONFIGFS_ATTR(interval, ulong);
+FAULT_CONFIGFS_ATTR(times, atomic_t);
+FAULT_CONFIGFS_ATTR(space, atomic_t);
+FAULT_CONFIGFS_ATTR(verbose, ulong);
+FAULT_CONFIGFS_ATTR_NAMED(ratelimit_interval, "verbose_ratelimit_interval_ms",
+ ratelimit_state.interval, uint);
+FAULT_CONFIGFS_ATTR_NAMED(ratelimit_burst, "verbose_ratelimit_burst",
+ ratelimit_state.burst, uint);
+FAULT_CONFIGFS_ATTR_NAMED(task_filter, "task-filter", task_filter, bool);
+
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+
+static ssize_t fault_stacktrace_depth_show(struct config_item *item, char *page)
+{
+ return fault_ulong_attr_show(to_fault_config(item)->attr.stacktrace_depth, page);
+}
+
+static ssize_t fault_stacktrace_depth_store(struct config_item *item, const char *page,
+ size_t count)
+{
+ int result;
+ unsigned long tmp;
+
+ result = kstrtoul(page, 0, &tmp);
+ if (result < 0)
+ return result;
+
+ to_fault_config(item)->attr.stacktrace_depth =
+ min_t(unsigned long, tmp, MAX_STACK_TRACE_DEPTH);
+
+ return count;
+}
+
+CONFIGFS_ATTR_NAMED(fault_, stacktrace_depth, "stacktrace-depth");
+
+static ssize_t fault_xul_attr_show(unsigned long val, char *page)
+{
+ return snprintf(page, PAGE_SIZE,
+ sizeof(val) == sizeof(u32) ? "0x%08lx\n" : "0x%016lx\n", val);
+}
+
+static ssize_t fault_xul_attr_store(unsigned long *val, const char *page, size_t count)
+{
+ return fault_ulong_attr_store(val, page, count);
+}
+
+FAULT_CONFIGFS_ATTR_NAMED(require_start, "require-start", require_start, xul);
+FAULT_CONFIGFS_ATTR_NAMED(require_end, "require-end", require_end, xul);
+FAULT_CONFIGFS_ATTR_NAMED(reject_start, "reject-start", reject_start, xul);
+FAULT_CONFIGFS_ATTR_NAMED(reject_end, "reject-end", reject_end, xul);
+
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+
+static struct configfs_attribute *fault_config_attrs[] = {
+ &fault_attr_probability,
+ &fault_attr_interval,
+ &fault_attr_times,
+ &fault_attr_space,
+ &fault_attr_verbose,
+ &fault_attr_ratelimit_interval,
+ &fault_attr_ratelimit_burst,
+ &fault_attr_task_filter,
+#ifdef CONFIG_FAULT_INJECTION_STACKTRACE_FILTER
+ &fault_attr_stacktrace_depth,
+ &fault_attr_require_start,
+ &fault_attr_require_end,
+ &fault_attr_reject_start,
+ &fault_attr_reject_end,
+#endif /* CONFIG_FAULT_INJECTION_STACKTRACE_FILTER */
+ NULL,
+};
+
+static const struct config_item_type fault_config_type = {
+ .ct_attrs = fault_config_attrs,
+ .ct_owner = THIS_MODULE,
+};
+
+void fault_config_init(struct fault_config *config, const char *name)
+{
+ prandom_init_once(&fault_rnd_state);
+
+ config_group_init_type_name(&config->group, name, &fault_config_type);
+}
+EXPORT_SYMBOL_GPL(fault_config_init);
+
+#endif /* CONFIG_FAULT_INJECTION_CONFIGFS */