From 22098763a10d9c1340827fcf6edab66f153b27f0 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sun, 13 Sep 2026 12:27:00 -0700 Subject: Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing fixes from Steven Rostedt: - Don't destroy user event fields when removal fails User event fields are destroyed before the event is removed from visibility. But that can fail leaving the still visible event with no fields. Move the destroying of the fields to after the event is successfully removed from visibility. - Initialize function graph state is fork before calling copy_exec_state() For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state. If that allocation fails, ftrace_graph_exit_task() will free the tasks ret_stack pointer. Since that pointer is still using the parent's ret_stack, it mistakenly frees the parent's pointer too. Call ftrace_graph_init() on the task first which will NULL out the new tasks's ret_stack and if the copy fails, it will not free anything. - Remove FGRAPH_MAX_INDEX The macro FGRAPH_MAX_INDEX was added but never used. Remove it. - Save ent_size in function graph printing of nested functions The function graph tracer needs to look at the next event to see if the next event is the return of the current function entry. If it is, it prints a single line: ktime_get(); Otherwise it prints it like a nested function: tick_nohz_irq_exit() { ktime_get(); kcpustat_irq_exit(); } In order to look at the next event, it must save the current event so that it has the information to print from it. It saves the event in the iterator descriptor called "ent". What it doesn't save is the ent_size of the event which is now used to know if the function graph arguments are to be printed. The peek doesn't save the size so the size used happens to be that of the size of the last event that was seen. Save the entry event size in the iterator descriptor so that the correct size is used. - Fix several errors with freeing data in the histogram code The histogram code had a lot of leaked or or incorrect accounting when failures happen. Correct them. - Fix histogram regression of .percent and .graph modifiers Up until 6.3 histogram values could have "percent" or "graph" modifiers that changed how they were printed. But a change that added restricting histograms values from being strings, stack traces and other modifiers inadvertently prevented them from using the percent and graph modifiers, which were legal use cases for values. Put back the percent and graph modifiers. - Fix various typos in the comments - Set the trace_clock before initializing a histogram with clock argument The histogram API allows the user to specific which trace clock to use via a "clock=" string. The histogram is set up first before the clock is checked. If the passed in clock is not valid, it exits without fully fixing up the histogram leaving it on the list and a use-after-free can trigger. Update the clock argument first and if it fails then exit gracefully before the histogram trigger is placed on any lists. - Restore :mod: trailer after parsing in ftrace_set_clr_event The function ftrace_set_clr_event() modifies the parse string and needs to put it back to what was passed in. It searches for ":mod:" via a strsep() but fails to put back the first ':' in the string. Add back the ':' in the passed in string. - Take trace_array reference when opening a tracer options file The options files are dynamically created and some tracers add their own options. When a tracer adds their own list of options, the trace_array holding them has an array to hold the list of options for each tracer. This array increases in size via a krealloc(), and the new entry gets a newly allocated array to hold the options of the new tracer being added. The element in each entry of the tracer's option array holds a pointer back to the trace_array, a pointer to the tracer it is associated to, a pointer to the flags of the option. The issue is that these arrays are freed when the trace_array is freed when its instance it represents is removed from the instances directory. There's a race that an open of one of these options files can happen when the instance is being removed. Add a new helper function to be called by the open function of the options file to iterate all existing trace_arrays under a lock and find the one that has the given option element in one of it's tracer arrays. If found, then update the associated trace_array's reference counter to keep it from being freed. If not found, have the open call return -ENODEV. - Disable interrupts when acquiring the lock in rb_wake_up_waiters() The function rb_wake_up_waiters() assumes it will be called in interrupt context and does not disable irqs when taking cpu_buffer->reader_lock, which can be called in hard interrupt context. The issue is in PREEMPT_RT, this function is called in thread context leaving this lock open to a deadlock. Take the lock with interrupts disabled. - Use rcu_assign_pointer() for tmp_ops filter hash The tmp_ops used in update_ftrace_direct_mod() assigns its filter_hash field directly, but that field is annotated as __rcu and sparse complains. Assign it with rcu_assign_pointer() - Fix use-after-free in enable_trigger_private_data_free() The trace_event_call is accessed through the event_trigger_data's trace_event_file pointer to put the trace_event_call on freeing. The issue is that the trace_event_file data may have been freed already causing a use-after-free. Add a field to the event_trigger_data that points directly to the trace_event_call so that it can decrement its reference directly without needing to go through the trace_event_file. - Fix accounting of buffer data remote headers trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount the number of pages is needed for the asked for size as it doesn't take into account the meta data on each page. Add a helper function to do the calculation properly and use that in these functions. - Catch nr_page_va overflow in ring_buffer_desc sizing The number of pages per remote ring buffer is capped by ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to overflow that field would silently allocate a descriptor smaller than what was asked for. - Do not resize the subbuf order if any per_cpu buffer is disabled The mmapping of ring buffers disables resizing the subbuffers, but it is done per-cpu whereas the subbuf size change is done for all the per_cpu buffers under the buffer->mutex. It could change the size of some while the mapping is happening on others. Have the resize of the subbuf order check all the per_cpu buffers under the lock to see if any of them is disabled before starting and causing an inconsistency between buffers that are being mapped. * tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits) ring-buffer: Check resize_disabled before publishing the new subbuf order tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing tracing/remotes: Account for ring buffer page header in size calculation tracing: Don't dereference trace_event_file in deferred trigger free ftrace: Use rcu_assign_pointer() for tmp_ops filter hash ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters() tracing: Take trace_array reference when opening a tracer options file tracing: Fix ring_buffer_read_page_size() kernel-doc tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event() tracing: Fix memory corruption from a "STACKTRACE" histogram key tracing: Fix memory corruption from the histogram stacktrace modifier tracing: Undo the registration when enabling the histogram trigger fails tracing: Take the reference before publishing the named histogram trigger tracing: Set the trace clock before registering the histogram trigger tracing: Fix typo "preceeded" in comment tracing: Fix typo "availabe" in comment tracing: Let histogram values keep the percent and graph modifiers tracing: Keep the entry count when the histogram stats allocation fails tracing: Free histogram the field rejected for a bad modifier tracing: Free histogram the var ref when its initialization fails ... --- lib/cpu_rmap.c | 339 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 339 insertions(+) create mode 100644 lib/cpu_rmap.c (limited to 'lib/cpu_rmap.c') diff --git a/lib/cpu_rmap.c b/lib/cpu_rmap.c new file mode 100644 index 000000000..c86ab6e55 --- /dev/null +++ b/lib/cpu_rmap.c @@ -0,0 +1,339 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * cpu_rmap.c: CPU affinity reverse-map support + * Copyright 2011 Solarflare Communications Inc. + */ + +#include +#include +#include + +/* + * These functions maintain a mapping from CPUs to some ordered set of + * objects with CPU affinities. This can be seen as a reverse-map of + * CPU affinity. However, we do not assume that the object affinities + * cover all CPUs in the system. For those CPUs not directly covered + * by object affinities, we attempt to find a nearest object based on + * CPU topology. + */ + +/** + * alloc_cpu_rmap - allocate CPU affinity reverse-map + * @size: Number of objects to be mapped + * @flags: Allocation flags e.g. %GFP_KERNEL + */ +struct cpu_rmap *alloc_cpu_rmap(unsigned int size, gfp_t flags) +{ + struct cpu_rmap *rmap; + unsigned int cpu; + size_t obj_offset; + + /* This is a silly number of objects, and we use u16 indices. */ + if (size > 0xffff) + return NULL; + + /* Offset of object pointer array from base structure */ + obj_offset = ALIGN(offsetof(struct cpu_rmap, near[nr_cpu_ids]), + sizeof(void *)); + + rmap = kzalloc(obj_offset + size * sizeof(rmap->obj[0]), flags); + if (!rmap) + return NULL; + + kref_init(&rmap->refcount); + rmap->obj = (void **)((char *)rmap + obj_offset); + + /* Initially assign CPUs to objects on a rota, since we have + * no idea where the objects are. Use infinite distance, so + * any object with known distance is preferable. Include the + * CPUs that are not present/online, since we definitely want + * any newly-hotplugged CPUs to have some object assigned. + */ + for_each_possible_cpu(cpu) { + rmap->near[cpu].index = cpu % size; + rmap->near[cpu].dist = CPU_RMAP_DIST_INF; + } + + rmap->size = size; + return rmap; +} +EXPORT_SYMBOL(alloc_cpu_rmap); + +/** + * cpu_rmap_release - internal reclaiming helper called from kref_put + * @ref: kref to struct cpu_rmap + */ +static void cpu_rmap_release(struct kref *ref) +{ + struct cpu_rmap *rmap = container_of(ref, struct cpu_rmap, refcount); + kfree(rmap); +} + +/** + * cpu_rmap_get - internal helper to get new ref on a cpu_rmap + * @rmap: reverse-map allocated with alloc_cpu_rmap() + */ +void cpu_rmap_get(struct cpu_rmap *rmap) +{ + kref_get(&rmap->refcount); +} + +/** + * cpu_rmap_put - release ref on a cpu_rmap + * @rmap: reverse-map allocated with alloc_cpu_rmap() + */ +int cpu_rmap_put(struct cpu_rmap *rmap) +{ + return kref_put(&rmap->refcount, cpu_rmap_release); +} +EXPORT_SYMBOL(cpu_rmap_put); + +/* Reevaluate nearest object for given CPU, comparing with the given + * neighbours at the given distance. + */ +static bool cpu_rmap_copy_neigh(struct cpu_rmap *rmap, unsigned int cpu, + const struct cpumask *mask, u16 dist) +{ + int neigh; + + for_each_cpu(neigh, mask) { + if (rmap->near[cpu].dist > dist && + rmap->near[neigh].dist <= dist) { + rmap->near[cpu].index = rmap->near[neigh].index; + rmap->near[cpu].dist = dist; + return true; + } + } + return false; +} + +#ifdef DEBUG +static void debug_print_rmap(const struct cpu_rmap *rmap, const char *prefix) +{ + unsigned index; + unsigned int cpu; + + pr_info("cpu_rmap %p, %s:\n", rmap, prefix); + + for_each_possible_cpu(cpu) { + index = rmap->near[cpu].index; + pr_info("cpu %d -> obj %u (distance %u)\n", + cpu, index, rmap->near[cpu].dist); + } +} +#else +static inline void +debug_print_rmap(const struct cpu_rmap *rmap, const char *prefix) +{ +} +#endif + +static int get_free_index(struct cpu_rmap *rmap) +{ + int i; + + for (i = 0; i < rmap->size; i++) + if (!rmap->obj[i]) + return i; + + return -ENOSPC; +} + +/** + * cpu_rmap_add - add object to a rmap + * @rmap: CPU rmap allocated with alloc_cpu_rmap() + * @obj: Object to add to rmap + * + * Return index of object or -ENOSPC if no free entry was found + */ +int cpu_rmap_add(struct cpu_rmap *rmap, void *obj) +{ + int index = get_free_index(rmap); + + if (index < 0) + return index; + + rmap->obj[index] = obj; + return index; +} +EXPORT_SYMBOL(cpu_rmap_add); + +/** + * cpu_rmap_update - update CPU rmap following a change of object affinity + * @rmap: CPU rmap to update + * @index: Index of object whose affinity changed + * @affinity: New CPU affinity of object + */ +int cpu_rmap_update(struct cpu_rmap *rmap, u16 index, + const struct cpumask *affinity) +{ + cpumask_var_t update_mask; + unsigned int cpu; + + if (unlikely(!zalloc_cpumask_var(&update_mask, GFP_KERNEL))) + return -ENOMEM; + + /* Invalidate distance for all CPUs for which this used to be + * the nearest object. Mark those CPUs for update. + */ + for_each_online_cpu(cpu) { + if (rmap->near[cpu].index == index) { + rmap->near[cpu].dist = CPU_RMAP_DIST_INF; + cpumask_set_cpu(cpu, update_mask); + } + } + + debug_print_rmap(rmap, "after invalidating old distances"); + + /* Set distance to 0 for all CPUs in the new affinity mask. + * Mark all CPUs within their NUMA nodes for update. + */ + for_each_cpu(cpu, affinity) { + rmap->near[cpu].index = index; + rmap->near[cpu].dist = 0; + cpumask_or(update_mask, update_mask, + cpumask_of_node(cpu_to_node(cpu))); + } + + debug_print_rmap(rmap, "after updating neighbours"); + + /* Update distances based on topology */ + for_each_cpu(cpu, update_mask) { + if (cpu_rmap_copy_neigh(rmap, cpu, + topology_sibling_cpumask(cpu), 1)) + continue; + if (cpu_rmap_copy_neigh(rmap, cpu, + topology_core_cpumask(cpu), 2)) + continue; + if (cpu_rmap_copy_neigh(rmap, cpu, + cpumask_of_node(cpu_to_node(cpu)), 3)) + continue; + /* We could continue into NUMA node distances, but for now + * we give up. + */ + } + + debug_print_rmap(rmap, "after copying neighbours"); + + free_cpumask_var(update_mask); + return 0; +} +EXPORT_SYMBOL(cpu_rmap_update); + +/* Glue between IRQ affinity notifiers and CPU rmaps */ + +struct irq_glue { + struct irq_affinity_notify notify; + struct cpu_rmap *rmap; + u16 index; +}; + +/** + * free_irq_cpu_rmap - free a CPU affinity reverse-map used for IRQs + * @rmap: Reverse-map allocated with alloc_irq_cpu_map(), or %NULL + * + * Must be called in process context, before freeing the IRQs. + */ +void free_irq_cpu_rmap(struct cpu_rmap *rmap) +{ + struct irq_glue *glue; + u16 index; + + if (!rmap) + return; + + for (index = 0; index < rmap->size; index++) { + glue = rmap->obj[index]; + if (glue) + irq_set_affinity_notifier(glue->notify.irq, NULL); + } + + cpu_rmap_put(rmap); +} +EXPORT_SYMBOL(free_irq_cpu_rmap); + +/** + * irq_cpu_rmap_notify - callback for IRQ subsystem when IRQ affinity updated + * @notify: struct irq_affinity_notify passed by irq/manage.c + * @mask: cpu mask for new SMP affinity + * + * This is executed in workqueue context. + */ +static void +irq_cpu_rmap_notify(struct irq_affinity_notify *notify, const cpumask_t *mask) +{ + struct irq_glue *glue = + container_of(notify, struct irq_glue, notify); + int rc; + + rc = cpu_rmap_update(glue->rmap, glue->index, mask); + if (rc) + pr_warn("irq_cpu_rmap_notify: update failed: %d\n", rc); +} + +/** + * irq_cpu_rmap_release - reclaiming callback for IRQ subsystem + * @ref: kref to struct irq_affinity_notify passed by irq/manage.c + */ +static void irq_cpu_rmap_release(struct kref *ref) +{ + struct irq_glue *glue = + container_of(ref, struct irq_glue, notify.kref); + + glue->rmap->obj[glue->index] = NULL; + cpu_rmap_put(glue->rmap); + kfree(glue); +} + +/** + * irq_cpu_rmap_remove - remove an IRQ from a CPU affinity reverse-map + * @rmap: The reverse-map + * @irq: The IRQ number + */ +int irq_cpu_rmap_remove(struct cpu_rmap *rmap, int irq) +{ + return irq_set_affinity_notifier(irq, NULL); +} +EXPORT_SYMBOL(irq_cpu_rmap_remove); + +/** + * irq_cpu_rmap_add - add an IRQ to a CPU affinity reverse-map + * @rmap: The reverse-map + * @irq: The IRQ number + * + * This adds an IRQ affinity notifier that will update the reverse-map + * automatically. + * + * Must be called in process context, after the IRQ is allocated but + * before it is bound with request_irq(). + */ +int irq_cpu_rmap_add(struct cpu_rmap *rmap, int irq) +{ + struct irq_glue *glue = kzalloc_obj(*glue); + int rc; + + if (!glue) + return -ENOMEM; + glue->notify.notify = irq_cpu_rmap_notify; + glue->notify.release = irq_cpu_rmap_release; + glue->rmap = rmap; + cpu_rmap_get(rmap); + rc = cpu_rmap_add(rmap, glue); + if (rc < 0) + goto err_add; + + glue->index = rc; + rc = irq_set_affinity_notifier(irq, &glue->notify); + if (rc) + goto err_set; + + return rc; + +err_set: + rmap->obj[glue->index] = NULL; +err_add: + cpu_rmap_put(glue->rmap); + kfree(glue); + return rc; +} +EXPORT_SYMBOL(irq_cpu_rmap_add); -- cgit v1.3.1