Commit 023cc836 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'probes-fixes-v6.6-rc6.2' of... 

Merge tag 'probes-fixes-v6.6-rc6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

Pull probes fixes from Masami Hiramatsu:

 - kprobe-events: Fix kprobe events to reject if the attached symbol is
   not unique name because it may not the function which the user want
   to attach to. (User can attach a probe to such symbol using the
   nearest unique symbol + offset.)

 - selftest: Add a testcase to ensure the kprobe event rejects non
   unique symbol correctly.

* tag 'probes-fixes-v6.6-rc6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  selftests/ftrace: Add new test case which checks non unique symbol
  tracing/kprobes: Return EADDRNOTAVAIL when func matches several symbols
parents 4d7b04c0 03b80ff8

kernel/trace/trace_kprobe.c

+63 −0
Original line number Diff line number Diff line
@@ -705,6 +705,25 @@ static struct notifier_block trace_kprobe_module_nb = { 
	.priority = 1	/* Invoked after kprobe module callback */

};



static int count_symbols(void *data, unsigned long unused)

{

	unsigned int *count = data;



	(*count)++;



	return 0;

}



static unsigned int number_of_same_symbols(char *func_name)

{

	unsigned int count;



	count = 0;

	kallsyms_on_each_match_symbol(count_symbols, func_name, &count);



	return count;

}



static int __trace_kprobe_create(int argc, const char *argv[])

{

	/*
@@ -836,6 +855,31 @@ static int __trace_kprobe_create(int argc, const char *argv[]) 
		}

	}



	if (symbol && !strchr(symbol, ':')) {

		unsigned int count;



		count = number_of_same_symbols(symbol);

		if (count > 1) {

			/*

			 * Users should use ADDR to remove the ambiguity of

			 * using KSYM only.

			 */

			trace_probe_log_err(0, NON_UNIQ_SYMBOL);

			ret = -EADDRNOTAVAIL;



			goto error;

		} else if (count == 0) {

			/*

			 * We can return ENOENT earlier than when register the

			 * kprobe.

			 */

			trace_probe_log_err(0, BAD_PROBE_ADDR);

			ret = -ENOENT;



			goto error;

		}

	}



	trace_probe_log_set_index(0);

	if (event) {

		ret = traceprobe_parse_event_name(&event, &group, gbuf,
@@ -1695,6 +1739,7 @@ static int unregister_kprobe_event(struct trace_kprobe *tk) 
}



#ifdef CONFIG_PERF_EVENTS



/* create a trace_kprobe, but don't add it to global lists */

struct trace_event_call *

create_local_trace_kprobe(char *func, void *addr, unsigned long offs,
@@ -1705,6 +1750,24 @@ create_local_trace_kprobe(char *func, void *addr, unsigned long offs, 
	int ret;

	char *event;



	if (func) {

		unsigned int count;



		count = number_of_same_symbols(func);

		if (count > 1)

			/*

			 * Users should use addr to remove the ambiguity of

			 * using func only.

			 */

			return ERR_PTR(-EADDRNOTAVAIL);

		else if (count == 0)

			/*

			 * We can return ENOENT earlier than when register the

			 * kprobe.

			 */

			return ERR_PTR(-ENOENT);

	}



	/*

	 * local trace_kprobes are not added to dyn_event, so they are never

	 * searched in find_trace_kprobe(). Therefore, there is no concern of

kernel/trace/trace_probe.h

+1 −0
Original line number Diff line number Diff line
@@ -450,6 +450,7 @@ extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, 
	C(BAD_MAXACT,		"Invalid maxactive number"),		\

	C(MAXACT_TOO_BIG,	"Maxactive is too big"),		\

	C(BAD_PROBE_ADDR,	"Invalid probed address or symbol"),	\

	C(NON_UNIQ_SYMBOL,	"The symbol is not unique"),		\

	C(BAD_RETPROBE,		"Retprobe address must be an function entry"), \

	C(NO_TRACEPOINT,	"Tracepoint is not found"),		\

	C(BAD_ADDR_SUFFIX,	"Invalid probed address suffix"), \

tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc

0 → 100644
+13 −0
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0

# description: Test failure of registering kprobe on non unique symbol

# requires: kprobe_events



SYMBOL='name_show'



# We skip this test on kernel where SYMBOL is unique or does not exist.

if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then

	exit_unsupported

fi



! echo "p:test_non_unique ${SYMBOL}" > kprobe_events