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kprobes: Add perf ksymbol events for kprobe insn pages

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Symbols are needed for tools to describe instruction addresses. Pages
allocated for kprobe's purposes need symbols to be created for them.
Add such symbols to be visible via perf ksymbol events.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20200512121922.8997-5-adrian.hunter@intel.com
This commit is contained in:
Adrian Hunter 2020-05-12 15:19:11 +03:00 committed by Peter Zijlstra
parent d002b8bc6d
commit 69e4908869
2 changed files with 17 additions and 0 deletions
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5
include/uapi/linux/perf_event.h
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@ -1049,6 +1049,11 @@ enum perf_event_type {
enum perf_record_ksymbol_type {
PERF_RECORD_KSYMBOL_TYPE_UNKNOWN = 0,
PERF_RECORD_KSYMBOL_TYPE_BPF = 1,
/*
* Out of line code such as kprobe-replaced instructions or optimized
* kprobes.
*/
PERF_RECORD_KSYMBOL_TYPE_OOL = 2,
PERF_RECORD_KSYMBOL_TYPE_MAX /* non-ABI */
};

12
kernel/kprobes.c
View File

@ -35,6 +35,7 @@
#include <linux/ftrace.h>
#include <linux/cpu.h>
#include <linux/jump_label.h>
#include <linux/perf_event.h>
#include <asm/sections.h>
#include <asm/cacheflush.h>
@ -184,6 +185,10 @@ kprobe_opcode_t *__get_insn_slot(struct kprobe_insn_cache *c)
kip->cache = c;
list_add_rcu(&kip->list, &c->pages);
slot = kip->insns;
/* Record the perf ksymbol register event after adding the page */
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL, (unsigned long)kip->insns,
PAGE_SIZE, false, c->sym);
out:
mutex_unlock(&c->mutex);
return slot;
@ -202,6 +207,13 @@ static int collect_one_slot(struct kprobe_insn_page *kip, int idx)
* next time somebody inserts a probe.
*/
if (!list_is_singular(&kip->list)) {
/*
* Record perf ksymbol unregister event before removing
* the page.
*/
perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_OOL,
(unsigned long)kip->insns, PAGE_SIZE, true,
kip->cache->sym);
list_del_rcu(&kip->list);
synchronize_rcu();
kip->cache->free(kip->insns);