336 lines
7.6 KiB
C
336 lines
7.6 KiB
C
/*
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* Copyright (C) 2008 Pekka Enberg, Eduard - Gabriel Munteanu
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*
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* This file is released under GPL version 2.
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*/
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#include <linux/string.h>
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#include <linux/debugfs.h>
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#include <linux/relay.h>
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#include <linux/module.h>
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#include <linux/marker.h>
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#include <linux/gfp.h>
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#include <linux/kmemtrace.h>
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#define KMEMTRACE_SUBBUF_SIZE 524288
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#define KMEMTRACE_DEF_N_SUBBUFS 20
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static struct rchan *kmemtrace_chan;
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static u32 kmemtrace_buf_overruns;
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static unsigned int kmemtrace_n_subbufs;
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#ifdef CONFIG_KMEMTRACE_DEFAULT_ENABLED
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static unsigned int kmemtrace_enabled = 1;
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#else
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static unsigned int kmemtrace_enabled = 0;
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#endif
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/*
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* The sequence number is used for reordering kmemtrace packets
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* in userspace, since they are logged as per-CPU data.
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*
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* atomic_t should always be a 32-bit signed integer. Wraparound is not
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* likely to occur, but userspace can deal with it by expecting a certain
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* sequence number in the next packet that will be read.
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*/
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static atomic_t kmemtrace_seq_num;
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#define KMEMTRACE_ABI_VERSION 1
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static u32 kmemtrace_abi_version __read_mostly = KMEMTRACE_ABI_VERSION;
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enum kmemtrace_event_id {
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KMEMTRACE_EVENT_ALLOC = 0,
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KMEMTRACE_EVENT_FREE,
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};
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struct kmemtrace_event {
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u8 event_id;
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u8 type_id;
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u16 event_size;
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s32 seq_num;
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u64 call_site;
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u64 ptr;
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} __attribute__ ((__packed__));
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struct kmemtrace_stats_alloc {
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u64 bytes_req;
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u64 bytes_alloc;
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u32 gfp_flags;
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s32 numa_node;
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} __attribute__ ((__packed__));
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static void kmemtrace_probe_alloc(void *probe_data, void *call_data,
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const char *format, va_list *args)
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{
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unsigned long flags;
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struct kmemtrace_event *ev;
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struct kmemtrace_stats_alloc *stats;
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void *buf;
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local_irq_save(flags);
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buf = relay_reserve(kmemtrace_chan,
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sizeof(struct kmemtrace_event) +
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sizeof(struct kmemtrace_stats_alloc));
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if (!buf)
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goto failed;
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/*
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* Don't convert this to use structure initializers,
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* C99 does not guarantee the rvalues evaluation order.
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*/
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ev = buf;
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ev->event_id = KMEMTRACE_EVENT_ALLOC;
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ev->type_id = va_arg(*args, int);
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ev->event_size = sizeof(struct kmemtrace_event) +
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sizeof(struct kmemtrace_stats_alloc);
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ev->seq_num = atomic_add_return(1, &kmemtrace_seq_num);
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ev->call_site = va_arg(*args, unsigned long);
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ev->ptr = va_arg(*args, unsigned long);
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stats = buf + sizeof(struct kmemtrace_event);
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stats->bytes_req = va_arg(*args, unsigned long);
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stats->bytes_alloc = va_arg(*args, unsigned long);
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stats->gfp_flags = va_arg(*args, unsigned long);
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stats->numa_node = va_arg(*args, int);
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failed:
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local_irq_restore(flags);
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}
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static void kmemtrace_probe_free(void *probe_data, void *call_data,
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const char *format, va_list *args)
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{
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unsigned long flags;
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struct kmemtrace_event *ev;
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local_irq_save(flags);
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ev = relay_reserve(kmemtrace_chan, sizeof(struct kmemtrace_event));
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if (!ev)
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goto failed;
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/*
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* Don't convert this to use structure initializers,
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* C99 does not guarantee the rvalues evaluation order.
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*/
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ev->event_id = KMEMTRACE_EVENT_FREE;
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ev->type_id = va_arg(*args, int);
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ev->event_size = sizeof(struct kmemtrace_event);
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ev->seq_num = atomic_add_return(1, &kmemtrace_seq_num);
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ev->call_site = va_arg(*args, unsigned long);
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ev->ptr = va_arg(*args, unsigned long);
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failed:
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local_irq_restore(flags);
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}
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static struct dentry *
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kmemtrace_create_buf_file(const char *filename, struct dentry *parent,
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int mode, struct rchan_buf *buf, int *is_global)
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{
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return debugfs_create_file(filename, mode, parent, buf,
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&relay_file_operations);
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}
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static int kmemtrace_remove_buf_file(struct dentry *dentry)
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{
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debugfs_remove(dentry);
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return 0;
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}
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static int kmemtrace_subbuf_start(struct rchan_buf *buf,
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void *subbuf,
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void *prev_subbuf,
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size_t prev_padding)
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{
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if (relay_buf_full(buf)) {
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/*
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* We know it's not SMP-safe, but neither
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* debugfs_create_u32() is.
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*/
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kmemtrace_buf_overruns++;
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return 0;
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}
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return 1;
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}
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static struct rchan_callbacks relay_callbacks = {
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.create_buf_file = kmemtrace_create_buf_file,
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.remove_buf_file = kmemtrace_remove_buf_file,
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.subbuf_start = kmemtrace_subbuf_start,
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};
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static struct dentry *kmemtrace_dir;
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static struct dentry *kmemtrace_overruns_dentry;
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static struct dentry *kmemtrace_abi_version_dentry;
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static struct dentry *kmemtrace_enabled_dentry;
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static int kmemtrace_start_probes(void)
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{
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int err;
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err = marker_probe_register("kmemtrace_alloc", "type_id %d "
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"call_site %lu ptr %lu "
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"bytes_req %lu bytes_alloc %lu "
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"gfp_flags %lu node %d",
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kmemtrace_probe_alloc, NULL);
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if (err)
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return err;
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err = marker_probe_register("kmemtrace_free", "type_id %d "
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"call_site %lu ptr %lu",
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kmemtrace_probe_free, NULL);
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return err;
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}
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static void kmemtrace_stop_probes(void)
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{
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marker_probe_unregister("kmemtrace_alloc",
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kmemtrace_probe_alloc, NULL);
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marker_probe_unregister("kmemtrace_free",
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kmemtrace_probe_free, NULL);
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}
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static int kmemtrace_enabled_get(void *data, u64 *val)
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{
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*val = *((int *) data);
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return 0;
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}
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static int kmemtrace_enabled_set(void *data, u64 val)
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{
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u64 old_val = kmemtrace_enabled;
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*((int *) data) = !!val;
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if (old_val == val)
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return 0;
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if (val)
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kmemtrace_start_probes();
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else
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kmemtrace_stop_probes();
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return 0;
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}
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DEFINE_SIMPLE_ATTRIBUTE(kmemtrace_enabled_fops,
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kmemtrace_enabled_get,
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kmemtrace_enabled_set, "%llu\n");
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static void kmemtrace_cleanup(void)
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{
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if (kmemtrace_enabled_dentry)
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debugfs_remove(kmemtrace_enabled_dentry);
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kmemtrace_stop_probes();
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if (kmemtrace_abi_version_dentry)
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debugfs_remove(kmemtrace_abi_version_dentry);
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if (kmemtrace_overruns_dentry)
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debugfs_remove(kmemtrace_overruns_dentry);
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relay_close(kmemtrace_chan);
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kmemtrace_chan = NULL;
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if (kmemtrace_dir)
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debugfs_remove(kmemtrace_dir);
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}
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static int __init kmemtrace_setup_late(void)
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{
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if (!kmemtrace_chan)
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goto failed;
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kmemtrace_dir = debugfs_create_dir("kmemtrace", NULL);
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if (!kmemtrace_dir)
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goto cleanup;
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kmemtrace_abi_version_dentry =
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debugfs_create_u32("abi_version", S_IRUSR,
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kmemtrace_dir, &kmemtrace_abi_version);
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kmemtrace_overruns_dentry =
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debugfs_create_u32("total_overruns", S_IRUSR,
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kmemtrace_dir, &kmemtrace_buf_overruns);
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if (!kmemtrace_overruns_dentry || !kmemtrace_abi_version_dentry)
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goto cleanup;
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kmemtrace_enabled_dentry =
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debugfs_create_file("enabled", S_IRUSR | S_IWUSR,
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kmemtrace_dir, &kmemtrace_enabled,
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&kmemtrace_enabled_fops);
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if (!kmemtrace_enabled_dentry)
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goto cleanup;
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if (relay_late_setup_files(kmemtrace_chan, "cpu", kmemtrace_dir))
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goto cleanup;
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printk(KERN_INFO "kmemtrace: fully up.\n");
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return 0;
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cleanup:
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kmemtrace_cleanup();
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failed:
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return 1;
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}
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late_initcall(kmemtrace_setup_late);
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static int __init kmemtrace_set_boot_enabled(char *str)
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{
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if (!str)
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return -EINVAL;
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if (!strcmp(str, "yes"))
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kmemtrace_enabled = 1;
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else if (!strcmp(str, "no"))
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kmemtrace_enabled = 0;
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else
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return -EINVAL;
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return 0;
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}
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early_param("kmemtrace.enable", kmemtrace_set_boot_enabled);
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static int __init kmemtrace_set_subbufs(char *str)
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{
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get_option(&str, &kmemtrace_n_subbufs);
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return 0;
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}
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early_param("kmemtrace.subbufs", kmemtrace_set_subbufs);
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void kmemtrace_init(void)
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{
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if (!kmemtrace_enabled)
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return;
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if (!kmemtrace_n_subbufs)
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kmemtrace_n_subbufs = KMEMTRACE_DEF_N_SUBBUFS;
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kmemtrace_chan = relay_open(NULL, NULL, KMEMTRACE_SUBBUF_SIZE,
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kmemtrace_n_subbufs, &relay_callbacks,
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NULL);
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if (unlikely(!kmemtrace_chan)) {
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printk(KERN_ERR "kmemtrace: could not open relay channel.\n");
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return;
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}
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if (unlikely(kmemtrace_start_probes()))
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goto probe_fail;
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printk(KERN_INFO "kmemtrace: early init successful.\n");
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return;
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probe_fail:
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printk(KERN_ERR "kmemtrace: could not register marker probes!\n");
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kmemtrace_cleanup();
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}
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