1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (c) 2016 Facebook
5 #include <linux/jhash.h>
6 #include <linux/filter.h>
7 #include <linux/kernel.h>
8 #include <linux/stacktrace.h>
9 #include <linux/perf_event.h>
10 #include <linux/elf.h>
11 #include <linux/pagemap.h>
12 #include <linux/irq_work.h>
13 #include <linux/btf_ids.h>
14 #include "percpu_freelist.h"
16 #define STACK_CREATE_FLAG_MASK \
17 (BPF_F_NUMA_NODE | BPF_F_RDONLY | BPF_F_WRONLY | \
20 struct stack_map_bucket {
21 struct pcpu_freelist_node fnode;
27 struct bpf_stack_map {
30 struct pcpu_freelist freelist;
32 struct stack_map_bucket *buckets[];
35 /* irq_work to run up_read() for build_id lookup in nmi context */
36 struct stack_map_irq_work {
37 struct irq_work irq_work;
41 static void do_up_read(struct irq_work *entry)
43 struct stack_map_irq_work *work;
45 if (WARN_ON_ONCE(IS_ENABLED(CONFIG_PREEMPT_RT)))
48 work = container_of(entry, struct stack_map_irq_work, irq_work);
49 mmap_read_unlock_non_owner(work->mm);
52 static DEFINE_PER_CPU(struct stack_map_irq_work, up_read_work);
54 static inline bool stack_map_use_build_id(struct bpf_map *map)
56 return (map->map_flags & BPF_F_STACK_BUILD_ID);
59 static inline int stack_map_data_size(struct bpf_map *map)
61 return stack_map_use_build_id(map) ?
62 sizeof(struct bpf_stack_build_id) : sizeof(u64);
65 static int prealloc_elems_and_freelist(struct bpf_stack_map *smap)
67 u32 elem_size = sizeof(struct stack_map_bucket) + smap->map.value_size;
70 smap->elems = bpf_map_area_alloc(elem_size * smap->map.max_entries,
75 err = pcpu_freelist_init(&smap->freelist);
79 pcpu_freelist_populate(&smap->freelist, smap->elems, elem_size,
80 smap->map.max_entries);
84 bpf_map_area_free(smap->elems);
88 /* Called from syscall */
89 static struct bpf_map *stack_map_alloc(union bpf_attr *attr)
91 u32 value_size = attr->value_size;
92 struct bpf_stack_map *smap;
93 struct bpf_map_memory mem;
98 return ERR_PTR(-EPERM);
100 if (attr->map_flags & ~STACK_CREATE_FLAG_MASK)
101 return ERR_PTR(-EINVAL);
103 /* check sanity of attributes */
104 if (attr->max_entries == 0 || attr->key_size != 4 ||
105 value_size < 8 || value_size % 8)
106 return ERR_PTR(-EINVAL);
108 BUILD_BUG_ON(sizeof(struct bpf_stack_build_id) % sizeof(u64));
109 if (attr->map_flags & BPF_F_STACK_BUILD_ID) {
110 if (value_size % sizeof(struct bpf_stack_build_id) ||
111 value_size / sizeof(struct bpf_stack_build_id)
112 > sysctl_perf_event_max_stack)
113 return ERR_PTR(-EINVAL);
114 } else if (value_size / 8 > sysctl_perf_event_max_stack)
115 return ERR_PTR(-EINVAL);
117 /* hash table size must be power of 2 */
118 n_buckets = roundup_pow_of_two(attr->max_entries);
120 cost = n_buckets * sizeof(struct stack_map_bucket *) + sizeof(*smap);
121 cost += n_buckets * (value_size + sizeof(struct stack_map_bucket));
122 err = bpf_map_charge_init(&mem, cost);
126 smap = bpf_map_area_alloc(cost, bpf_map_attr_numa_node(attr));
128 bpf_map_charge_finish(&mem);
129 return ERR_PTR(-ENOMEM);
132 bpf_map_init_from_attr(&smap->map, attr);
133 smap->map.value_size = value_size;
134 smap->n_buckets = n_buckets;
136 err = get_callchain_buffers(sysctl_perf_event_max_stack);
140 err = prealloc_elems_and_freelist(smap);
144 bpf_map_charge_move(&smap->map.memory, &mem);
149 put_callchain_buffers();
151 bpf_map_charge_finish(&mem);
152 bpf_map_area_free(smap);
156 #define BPF_BUILD_ID 3
158 * Parse build id from the note segment. This logic can be shared between
159 * 32-bit and 64-bit system, because Elf32_Nhdr and Elf64_Nhdr are
162 static inline int stack_map_parse_build_id(void *page_addr,
163 unsigned char *build_id,
165 Elf32_Word note_size)
167 Elf32_Word note_offs = 0, new_offs;
169 /* check for overflow */
170 if (note_start < page_addr || note_start + note_size < note_start)
173 /* only supports note that fits in the first page */
174 if (note_start + note_size > page_addr + PAGE_SIZE)
177 while (note_offs + sizeof(Elf32_Nhdr) < note_size) {
178 Elf32_Nhdr *nhdr = (Elf32_Nhdr *)(note_start + note_offs);
180 if (nhdr->n_type == BPF_BUILD_ID &&
181 nhdr->n_namesz == sizeof("GNU") &&
182 nhdr->n_descsz > 0 &&
183 nhdr->n_descsz <= BPF_BUILD_ID_SIZE) {
185 note_start + note_offs +
186 ALIGN(sizeof("GNU"), 4) + sizeof(Elf32_Nhdr),
188 memset(build_id + nhdr->n_descsz, 0,
189 BPF_BUILD_ID_SIZE - nhdr->n_descsz);
192 new_offs = note_offs + sizeof(Elf32_Nhdr) +
193 ALIGN(nhdr->n_namesz, 4) + ALIGN(nhdr->n_descsz, 4);
194 if (new_offs <= note_offs) /* overflow */
196 note_offs = new_offs;
201 /* Parse build ID from 32-bit ELF */
202 static int stack_map_get_build_id_32(void *page_addr,
203 unsigned char *build_id)
205 Elf32_Ehdr *ehdr = (Elf32_Ehdr *)page_addr;
209 /* only supports phdr that fits in one page */
211 (PAGE_SIZE - sizeof(Elf32_Ehdr)) / sizeof(Elf32_Phdr))
214 phdr = (Elf32_Phdr *)(page_addr + sizeof(Elf32_Ehdr));
216 for (i = 0; i < ehdr->e_phnum; ++i) {
217 if (phdr[i].p_type == PT_NOTE &&
218 !stack_map_parse_build_id(page_addr, build_id,
219 page_addr + phdr[i].p_offset,
226 /* Parse build ID from 64-bit ELF */
227 static int stack_map_get_build_id_64(void *page_addr,
228 unsigned char *build_id)
230 Elf64_Ehdr *ehdr = (Elf64_Ehdr *)page_addr;
234 /* only supports phdr that fits in one page */
236 (PAGE_SIZE - sizeof(Elf64_Ehdr)) / sizeof(Elf64_Phdr))
239 phdr = (Elf64_Phdr *)(page_addr + sizeof(Elf64_Ehdr));
241 for (i = 0; i < ehdr->e_phnum; ++i) {
242 if (phdr[i].p_type == PT_NOTE &&
243 !stack_map_parse_build_id(page_addr, build_id,
244 page_addr + phdr[i].p_offset,
251 /* Parse build ID of ELF file mapped to vma */
252 static int stack_map_get_build_id(struct vm_area_struct *vma,
253 unsigned char *build_id)
260 /* only works for page backed storage */
264 page = find_get_page(vma->vm_file->f_mapping, 0);
266 return -EFAULT; /* page not mapped */
269 page_addr = kmap_atomic(page);
270 ehdr = (Elf32_Ehdr *)page_addr;
272 /* compare magic x7f "ELF" */
273 if (memcmp(ehdr->e_ident, ELFMAG, SELFMAG) != 0)
276 /* only support executable file and shared object file */
277 if (ehdr->e_type != ET_EXEC && ehdr->e_type != ET_DYN)
280 if (ehdr->e_ident[EI_CLASS] == ELFCLASS32)
281 ret = stack_map_get_build_id_32(page_addr, build_id);
282 else if (ehdr->e_ident[EI_CLASS] == ELFCLASS64)
283 ret = stack_map_get_build_id_64(page_addr, build_id);
285 kunmap_atomic(page_addr);
290 static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
291 u64 *ips, u32 trace_nr, bool user)
294 struct vm_area_struct *vma;
295 bool irq_work_busy = false;
296 struct stack_map_irq_work *work = NULL;
298 if (irqs_disabled()) {
299 if (!IS_ENABLED(CONFIG_PREEMPT_RT)) {
300 work = this_cpu_ptr(&up_read_work);
301 if (irq_work_is_busy(&work->irq_work)) {
302 /* cannot queue more up_read, fallback */
303 irq_work_busy = true;
307 * PREEMPT_RT does not allow to trylock mmap sem in
308 * interrupt disabled context. Force the fallback code.
310 irq_work_busy = true;
315 * We cannot do up_read() when the irq is disabled, because of
316 * risk to deadlock with rq_lock. To do build_id lookup when the
317 * irqs are disabled, we need to run up_read() in irq_work. We use
318 * a percpu variable to do the irq_work. If the irq_work is
319 * already used by another lookup, we fall back to report ips.
321 * Same fallback is used for kernel stack (!user) on a stackmap
324 if (!user || !current || !current->mm || irq_work_busy ||
325 !mmap_read_trylock_non_owner(current->mm)) {
326 /* cannot access current->mm, fall back to ips */
327 for (i = 0; i < trace_nr; i++) {
328 id_offs[i].status = BPF_STACK_BUILD_ID_IP;
329 id_offs[i].ip = ips[i];
330 memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
335 for (i = 0; i < trace_nr; i++) {
336 vma = find_vma(current->mm, ips[i]);
337 if (!vma || stack_map_get_build_id(vma, id_offs[i].build_id)) {
338 /* per entry fall back to ips */
339 id_offs[i].status = BPF_STACK_BUILD_ID_IP;
340 id_offs[i].ip = ips[i];
341 memset(id_offs[i].build_id, 0, BPF_BUILD_ID_SIZE);
344 id_offs[i].offset = (vma->vm_pgoff << PAGE_SHIFT) + ips[i]
346 id_offs[i].status = BPF_STACK_BUILD_ID_VALID;
350 mmap_read_unlock_non_owner(current->mm);
352 work->mm = current->mm;
353 irq_work_queue(&work->irq_work);
357 static struct perf_callchain_entry *
358 get_callchain_entry_for_task(struct task_struct *task, u32 init_nr)
360 #ifdef CONFIG_STACKTRACE
361 struct perf_callchain_entry *entry;
364 entry = get_callchain_entry(&rctx);
369 entry->nr = init_nr +
370 stack_trace_save_tsk(task, (unsigned long *)(entry->ip + init_nr),
371 sysctl_perf_event_max_stack - init_nr, 0);
373 /* stack_trace_save_tsk() works on unsigned long array, while
374 * perf_callchain_entry uses u64 array. For 32-bit systems, it is
375 * necessary to fix this mismatch.
377 if (__BITS_PER_LONG != 64) {
378 unsigned long *from = (unsigned long *) entry->ip;
382 /* copy data from the end to avoid using extra buffer */
383 for (i = entry->nr - 1; i >= (int)init_nr; i--)
384 to[i] = (u64)(from[i]);
387 put_callchain_entry(rctx);
390 #else /* CONFIG_STACKTRACE */
395 static long __bpf_get_stackid(struct bpf_map *map,
396 struct perf_callchain_entry *trace, u64 flags)
398 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
399 struct stack_map_bucket *bucket, *new_bucket, *old_bucket;
400 u32 max_depth = map->value_size / stack_map_data_size(map);
401 /* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */
402 u32 init_nr = sysctl_perf_event_max_stack - max_depth;
403 u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
404 u32 hash, id, trace_nr, trace_len;
405 bool user = flags & BPF_F_USER_STACK;
409 /* get_perf_callchain() guarantees that trace->nr >= init_nr
410 * and trace-nr <= sysctl_perf_event_max_stack, so trace_nr <= max_depth
412 trace_nr = trace->nr - init_nr;
414 if (trace_nr <= skip)
415 /* skipping more than usable stack trace */
419 trace_len = trace_nr * sizeof(u64);
420 ips = trace->ip + skip + init_nr;
421 hash = jhash2((u32 *)ips, trace_len / sizeof(u32), 0);
422 id = hash & (smap->n_buckets - 1);
423 bucket = READ_ONCE(smap->buckets[id]);
425 hash_matches = bucket && bucket->hash == hash;
427 if (hash_matches && flags & BPF_F_FAST_STACK_CMP)
430 if (stack_map_use_build_id(map)) {
431 /* for build_id+offset, pop a bucket before slow cmp */
432 new_bucket = (struct stack_map_bucket *)
433 pcpu_freelist_pop(&smap->freelist);
434 if (unlikely(!new_bucket))
436 new_bucket->nr = trace_nr;
437 stack_map_get_build_id_offset(
438 (struct bpf_stack_build_id *)new_bucket->data,
439 ips, trace_nr, user);
440 trace_len = trace_nr * sizeof(struct bpf_stack_build_id);
441 if (hash_matches && bucket->nr == trace_nr &&
442 memcmp(bucket->data, new_bucket->data, trace_len) == 0) {
443 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
446 if (bucket && !(flags & BPF_F_REUSE_STACKID)) {
447 pcpu_freelist_push(&smap->freelist, &new_bucket->fnode);
451 if (hash_matches && bucket->nr == trace_nr &&
452 memcmp(bucket->data, ips, trace_len) == 0)
454 if (bucket && !(flags & BPF_F_REUSE_STACKID))
457 new_bucket = (struct stack_map_bucket *)
458 pcpu_freelist_pop(&smap->freelist);
459 if (unlikely(!new_bucket))
461 memcpy(new_bucket->data, ips, trace_len);
464 new_bucket->hash = hash;
465 new_bucket->nr = trace_nr;
467 old_bucket = xchg(&smap->buckets[id], new_bucket);
469 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
473 BPF_CALL_3(bpf_get_stackid, struct pt_regs *, regs, struct bpf_map *, map,
476 u32 max_depth = map->value_size / stack_map_data_size(map);
477 /* stack_map_alloc() checks that max_depth <= sysctl_perf_event_max_stack */
478 u32 init_nr = sysctl_perf_event_max_stack - max_depth;
479 bool user = flags & BPF_F_USER_STACK;
480 struct perf_callchain_entry *trace;
483 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
484 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
487 trace = get_perf_callchain(regs, init_nr, kernel, user,
488 sysctl_perf_event_max_stack, false, false);
490 if (unlikely(!trace))
491 /* couldn't fetch the stack trace */
494 return __bpf_get_stackid(map, trace, flags);
497 const struct bpf_func_proto bpf_get_stackid_proto = {
498 .func = bpf_get_stackid,
500 .ret_type = RET_INTEGER,
501 .arg1_type = ARG_PTR_TO_CTX,
502 .arg2_type = ARG_CONST_MAP_PTR,
503 .arg3_type = ARG_ANYTHING,
506 static __u64 count_kernel_ip(struct perf_callchain_entry *trace)
510 while (nr_kernel < trace->nr) {
511 if (trace->ip[nr_kernel] == PERF_CONTEXT_USER)
518 BPF_CALL_3(bpf_get_stackid_pe, struct bpf_perf_event_data_kern *, ctx,
519 struct bpf_map *, map, u64, flags)
521 struct perf_event *event = ctx->event;
522 struct perf_callchain_entry *trace;
527 /* perf_sample_data doesn't have callchain, use bpf_get_stackid */
528 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
529 return bpf_get_stackid((unsigned long)(ctx->regs),
530 (unsigned long) map, flags, 0, 0);
532 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
533 BPF_F_FAST_STACK_CMP | BPF_F_REUSE_STACKID)))
536 user = flags & BPF_F_USER_STACK;
539 trace = ctx->data->callchain;
540 if (unlikely(!trace))
543 nr_kernel = count_kernel_ip(trace);
546 __u64 nr = trace->nr;
548 trace->nr = nr_kernel;
549 ret = __bpf_get_stackid(map, trace, flags);
554 u64 skip = flags & BPF_F_SKIP_FIELD_MASK;
557 if (skip > BPF_F_SKIP_FIELD_MASK)
560 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;
561 ret = __bpf_get_stackid(map, trace, flags);
566 const struct bpf_func_proto bpf_get_stackid_proto_pe = {
567 .func = bpf_get_stackid_pe,
569 .ret_type = RET_INTEGER,
570 .arg1_type = ARG_PTR_TO_CTX,
571 .arg2_type = ARG_CONST_MAP_PTR,
572 .arg3_type = ARG_ANYTHING,
575 static long __bpf_get_stack(struct pt_regs *regs, struct task_struct *task,
576 struct perf_callchain_entry *trace_in,
577 void *buf, u32 size, u64 flags)
579 u32 init_nr, trace_nr, copy_len, elem_size, num_elem;
580 bool user_build_id = flags & BPF_F_USER_BUILD_ID;
581 u32 skip = flags & BPF_F_SKIP_FIELD_MASK;
582 bool user = flags & BPF_F_USER_STACK;
583 struct perf_callchain_entry *trace;
588 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
589 BPF_F_USER_BUILD_ID)))
591 if (kernel && user_build_id)
594 elem_size = (user && user_build_id) ? sizeof(struct bpf_stack_build_id)
596 if (unlikely(size % elem_size))
599 /* cannot get valid user stack for task without user_mode regs */
600 if (task && user && !user_mode(regs))
603 num_elem = size / elem_size;
604 if (sysctl_perf_event_max_stack < num_elem)
607 init_nr = sysctl_perf_event_max_stack - num_elem;
611 else if (kernel && task)
612 trace = get_callchain_entry_for_task(task, init_nr);
614 trace = get_perf_callchain(regs, init_nr, kernel, user,
615 sysctl_perf_event_max_stack,
617 if (unlikely(!trace))
620 trace_nr = trace->nr - init_nr;
625 trace_nr = (trace_nr <= num_elem) ? trace_nr : num_elem;
626 copy_len = trace_nr * elem_size;
627 ips = trace->ip + skip + init_nr;
628 if (user && user_build_id)
629 stack_map_get_build_id_offset(buf, ips, trace_nr, user);
631 memcpy(buf, ips, copy_len);
634 memset(buf + copy_len, 0, size - copy_len);
640 memset(buf, 0, size);
644 BPF_CALL_4(bpf_get_stack, struct pt_regs *, regs, void *, buf, u32, size,
647 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
650 const struct bpf_func_proto bpf_get_stack_proto = {
651 .func = bpf_get_stack,
653 .ret_type = RET_INTEGER,
654 .arg1_type = ARG_PTR_TO_CTX,
655 .arg2_type = ARG_PTR_TO_UNINIT_MEM,
656 .arg3_type = ARG_CONST_SIZE_OR_ZERO,
657 .arg4_type = ARG_ANYTHING,
660 BPF_CALL_4(bpf_get_task_stack, struct task_struct *, task, void *, buf,
661 u32, size, u64, flags)
663 struct pt_regs *regs = task_pt_regs(task);
665 return __bpf_get_stack(regs, task, NULL, buf, size, flags);
668 BTF_ID_LIST_SINGLE(bpf_get_task_stack_btf_ids, struct, task_struct)
670 const struct bpf_func_proto bpf_get_task_stack_proto = {
671 .func = bpf_get_task_stack,
673 .ret_type = RET_INTEGER,
674 .arg1_type = ARG_PTR_TO_BTF_ID,
675 .arg1_btf_id = &bpf_get_task_stack_btf_ids[0],
676 .arg2_type = ARG_PTR_TO_UNINIT_MEM,
677 .arg3_type = ARG_CONST_SIZE_OR_ZERO,
678 .arg4_type = ARG_ANYTHING,
681 BPF_CALL_4(bpf_get_stack_pe, struct bpf_perf_event_data_kern *, ctx,
682 void *, buf, u32, size, u64, flags)
684 struct pt_regs *regs = (struct pt_regs *)(ctx->regs);
685 struct perf_event *event = ctx->event;
686 struct perf_callchain_entry *trace;
691 if (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
692 return __bpf_get_stack(regs, NULL, NULL, buf, size, flags);
694 if (unlikely(flags & ~(BPF_F_SKIP_FIELD_MASK | BPF_F_USER_STACK |
695 BPF_F_USER_BUILD_ID)))
698 user = flags & BPF_F_USER_STACK;
702 trace = ctx->data->callchain;
703 if (unlikely(!trace))
706 nr_kernel = count_kernel_ip(trace);
709 __u64 nr = trace->nr;
711 trace->nr = nr_kernel;
712 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);
717 u64 skip = flags & BPF_F_SKIP_FIELD_MASK;
720 if (skip > BPF_F_SKIP_FIELD_MASK)
723 flags = (flags & ~BPF_F_SKIP_FIELD_MASK) | skip;
724 err = __bpf_get_stack(regs, NULL, trace, buf, size, flags);
729 memset(buf, 0, size);
734 const struct bpf_func_proto bpf_get_stack_proto_pe = {
735 .func = bpf_get_stack_pe,
737 .ret_type = RET_INTEGER,
738 .arg1_type = ARG_PTR_TO_CTX,
739 .arg2_type = ARG_PTR_TO_UNINIT_MEM,
740 .arg3_type = ARG_CONST_SIZE_OR_ZERO,
741 .arg4_type = ARG_ANYTHING,
744 /* Called from eBPF program */
745 static void *stack_map_lookup_elem(struct bpf_map *map, void *key)
747 return ERR_PTR(-EOPNOTSUPP);
750 /* Called from syscall */
751 int bpf_stackmap_copy(struct bpf_map *map, void *key, void *value)
753 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
754 struct stack_map_bucket *bucket, *old_bucket;
755 u32 id = *(u32 *)key, trace_len;
757 if (unlikely(id >= smap->n_buckets))
760 bucket = xchg(&smap->buckets[id], NULL);
764 trace_len = bucket->nr * stack_map_data_size(map);
765 memcpy(value, bucket->data, trace_len);
766 memset(value + trace_len, 0, map->value_size - trace_len);
768 old_bucket = xchg(&smap->buckets[id], bucket);
770 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
774 static int stack_map_get_next_key(struct bpf_map *map, void *key,
777 struct bpf_stack_map *smap = container_of(map,
778 struct bpf_stack_map, map);
781 WARN_ON_ONCE(!rcu_read_lock_held());
787 if (id >= smap->n_buckets || !smap->buckets[id])
793 while (id < smap->n_buckets && !smap->buckets[id])
796 if (id >= smap->n_buckets)
799 *(u32 *)next_key = id;
803 static int stack_map_update_elem(struct bpf_map *map, void *key, void *value,
809 /* Called from syscall or from eBPF program */
810 static int stack_map_delete_elem(struct bpf_map *map, void *key)
812 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
813 struct stack_map_bucket *old_bucket;
814 u32 id = *(u32 *)key;
816 if (unlikely(id >= smap->n_buckets))
819 old_bucket = xchg(&smap->buckets[id], NULL);
821 pcpu_freelist_push(&smap->freelist, &old_bucket->fnode);
828 /* Called when map->refcnt goes to zero, either from workqueue or from syscall */
829 static void stack_map_free(struct bpf_map *map)
831 struct bpf_stack_map *smap = container_of(map, struct bpf_stack_map, map);
833 bpf_map_area_free(smap->elems);
834 pcpu_freelist_destroy(&smap->freelist);
835 bpf_map_area_free(smap);
836 put_callchain_buffers();
839 static int stack_trace_map_btf_id;
840 const struct bpf_map_ops stack_trace_map_ops = {
841 .map_meta_equal = bpf_map_meta_equal,
842 .map_alloc = stack_map_alloc,
843 .map_free = stack_map_free,
844 .map_get_next_key = stack_map_get_next_key,
845 .map_lookup_elem = stack_map_lookup_elem,
846 .map_update_elem = stack_map_update_elem,
847 .map_delete_elem = stack_map_delete_elem,
848 .map_check_btf = map_check_no_btf,
849 .map_btf_name = "bpf_stack_map",
850 .map_btf_id = &stack_trace_map_btf_id,
853 static int __init stack_map_init(void)
856 struct stack_map_irq_work *work;
858 for_each_possible_cpu(cpu) {
859 work = per_cpu_ptr(&up_read_work, cpu);
860 init_irq_work(&work->irq_work, do_up_read);
864 subsys_initcall(stack_map_init);