mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-06 10:46:44 +07:00
fd45c15f13
When alloc_callchain_buffers() fails, it frees all of entries before return. In addition, calling the release_callchain_buffers() will cause a NULL pointer dereference since callchain_cpu_entries is not set. Signed-off-by: Namhyung Kim <namhyung.kim@lge.com> Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Link: http://lkml.kernel.org/r/1327021966-27688-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
190 lines
3.9 KiB
C
190 lines
3.9 KiB
C
/*
|
|
* Performance events callchain code, extracted from core.c:
|
|
*
|
|
* Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
|
|
* Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
|
|
* Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra <pzijlstr@redhat.com>
|
|
* Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
|
|
*
|
|
* For licensing details see kernel-base/COPYING
|
|
*/
|
|
|
|
#include <linux/perf_event.h>
|
|
#include <linux/slab.h>
|
|
#include "internal.h"
|
|
|
|
struct callchain_cpus_entries {
|
|
struct rcu_head rcu_head;
|
|
struct perf_callchain_entry *cpu_entries[0];
|
|
};
|
|
|
|
static DEFINE_PER_CPU(int, callchain_recursion[PERF_NR_CONTEXTS]);
|
|
static atomic_t nr_callchain_events;
|
|
static DEFINE_MUTEX(callchain_mutex);
|
|
static struct callchain_cpus_entries *callchain_cpus_entries;
|
|
|
|
|
|
__weak void perf_callchain_kernel(struct perf_callchain_entry *entry,
|
|
struct pt_regs *regs)
|
|
{
|
|
}
|
|
|
|
__weak void perf_callchain_user(struct perf_callchain_entry *entry,
|
|
struct pt_regs *regs)
|
|
{
|
|
}
|
|
|
|
static void release_callchain_buffers_rcu(struct rcu_head *head)
|
|
{
|
|
struct callchain_cpus_entries *entries;
|
|
int cpu;
|
|
|
|
entries = container_of(head, struct callchain_cpus_entries, rcu_head);
|
|
|
|
for_each_possible_cpu(cpu)
|
|
kfree(entries->cpu_entries[cpu]);
|
|
|
|
kfree(entries);
|
|
}
|
|
|
|
static void release_callchain_buffers(void)
|
|
{
|
|
struct callchain_cpus_entries *entries;
|
|
|
|
entries = callchain_cpus_entries;
|
|
rcu_assign_pointer(callchain_cpus_entries, NULL);
|
|
call_rcu(&entries->rcu_head, release_callchain_buffers_rcu);
|
|
}
|
|
|
|
static int alloc_callchain_buffers(void)
|
|
{
|
|
int cpu;
|
|
int size;
|
|
struct callchain_cpus_entries *entries;
|
|
|
|
/*
|
|
* We can't use the percpu allocation API for data that can be
|
|
* accessed from NMI. Use a temporary manual per cpu allocation
|
|
* until that gets sorted out.
|
|
*/
|
|
size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
|
|
|
|
entries = kzalloc(size, GFP_KERNEL);
|
|
if (!entries)
|
|
return -ENOMEM;
|
|
|
|
size = sizeof(struct perf_callchain_entry) * PERF_NR_CONTEXTS;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
entries->cpu_entries[cpu] = kmalloc_node(size, GFP_KERNEL,
|
|
cpu_to_node(cpu));
|
|
if (!entries->cpu_entries[cpu])
|
|
goto fail;
|
|
}
|
|
|
|
rcu_assign_pointer(callchain_cpus_entries, entries);
|
|
|
|
return 0;
|
|
|
|
fail:
|
|
for_each_possible_cpu(cpu)
|
|
kfree(entries->cpu_entries[cpu]);
|
|
kfree(entries);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
|
|
int get_callchain_buffers(void)
|
|
{
|
|
int err = 0;
|
|
int count;
|
|
|
|
mutex_lock(&callchain_mutex);
|
|
|
|
count = atomic_inc_return(&nr_callchain_events);
|
|
if (WARN_ON_ONCE(count < 1)) {
|
|
err = -EINVAL;
|
|
goto exit;
|
|
}
|
|
|
|
if (count > 1) {
|
|
/* If the allocation failed, give up */
|
|
if (!callchain_cpus_entries)
|
|
err = -ENOMEM;
|
|
goto exit;
|
|
}
|
|
|
|
err = alloc_callchain_buffers();
|
|
exit:
|
|
mutex_unlock(&callchain_mutex);
|
|
|
|
return err;
|
|
}
|
|
|
|
void put_callchain_buffers(void)
|
|
{
|
|
if (atomic_dec_and_mutex_lock(&nr_callchain_events, &callchain_mutex)) {
|
|
release_callchain_buffers();
|
|
mutex_unlock(&callchain_mutex);
|
|
}
|
|
}
|
|
|
|
static struct perf_callchain_entry *get_callchain_entry(int *rctx)
|
|
{
|
|
int cpu;
|
|
struct callchain_cpus_entries *entries;
|
|
|
|
*rctx = get_recursion_context(__get_cpu_var(callchain_recursion));
|
|
if (*rctx == -1)
|
|
return NULL;
|
|
|
|
entries = rcu_dereference(callchain_cpus_entries);
|
|
if (!entries)
|
|
return NULL;
|
|
|
|
cpu = smp_processor_id();
|
|
|
|
return &entries->cpu_entries[cpu][*rctx];
|
|
}
|
|
|
|
static void
|
|
put_callchain_entry(int rctx)
|
|
{
|
|
put_recursion_context(__get_cpu_var(callchain_recursion), rctx);
|
|
}
|
|
|
|
struct perf_callchain_entry *perf_callchain(struct pt_regs *regs)
|
|
{
|
|
int rctx;
|
|
struct perf_callchain_entry *entry;
|
|
|
|
|
|
entry = get_callchain_entry(&rctx);
|
|
if (rctx == -1)
|
|
return NULL;
|
|
|
|
if (!entry)
|
|
goto exit_put;
|
|
|
|
entry->nr = 0;
|
|
|
|
if (!user_mode(regs)) {
|
|
perf_callchain_store(entry, PERF_CONTEXT_KERNEL);
|
|
perf_callchain_kernel(entry, regs);
|
|
if (current->mm)
|
|
regs = task_pt_regs(current);
|
|
else
|
|
regs = NULL;
|
|
}
|
|
|
|
if (regs) {
|
|
perf_callchain_store(entry, PERF_CONTEXT_USER);
|
|
perf_callchain_user(entry, regs);
|
|
}
|
|
|
|
exit_put:
|
|
put_callchain_entry(rctx);
|
|
|
|
return entry;
|
|
}
|