linux-kernel - [tip:perf/core] perf probe: Fix kprobe blacklist checking condition

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Date:   Tue, 29 Aug 2017 14:25:33 -0700
From:   tip-bot for Li Bin <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     mingo@...nel.org, wangnan0@...wei.com, tglx@...utronix.de,
        namhyung@...nel.org, mhiramat@...nel.org, hpa@...or.com,
        acme@...hat.com, huawei.libin@...wei.com,
        linux-kernel@...r.kernel.org, peterz@...radead.org
Subject: [tip:perf/core] perf probe: Fix kprobe blacklist checking condition

Commit-ID:  2c29461e273abaf149cf8220c3403e9d67dd8b61
Gitweb:     http://git.kernel.org/tip/2c29461e273abaf149cf8220c3403e9d67dd8b61
Author:     Li Bin <huawei.libin@...wei.com>
AuthorDate: Tue, 29 Aug 2017 20:57:23 +0800
Committer:  Arnaldo Carvalho de Melo <acme@...hat.com>
CommitDate: Tue, 29 Aug 2017 11:14:12 -0300

perf probe: Fix kprobe blacklist checking condition

The commit 9aaf5a5f479b ("perf probe: Check kprobes blacklist when
adding new events"), 'perf probe' supports checking the blacklist of the
fuctions which can not be probed.  But the checking condition is wrong,
that the end_addr of the symbol which is the start_addr of the next
symbol can't be included.

Committer notes:

IOW make it match its kernel counterpart in kernel/kprobes.c:

  bool within_kprobe_blacklist(unsigned long addr)

Each entry have as its end address not its end address, but the first
address _outside_ that symbol, which for related functions, is the first
address of the next symbol, like these from kernel/trace/trace_probe.c:

0xffffffffbd198df0-0xffffffffbd198e40	print_type_u8
0xffffffffbd198e40-0xffffffffbd198e90	print_type_u16
0xffffffffbd198e90-0xffffffffbd198ee0	print_type_u32
0xffffffffbd198ee0-0xffffffffbd198f30	print_type_u64
0xffffffffbd198f30-0xffffffffbd198f80	print_type_s8
0xffffffffbd198f80-0xffffffffbd198fd0	print_type_s16
0xffffffffbd198fd0-0xffffffffbd199020	print_type_s32
0xffffffffbd199020-0xffffffffbd199070	print_type_s64
0xffffffffbd199070-0xffffffffbd1990c0	print_type_x8
0xffffffffbd1990c0-0xffffffffbd199110	print_type_x16
0xffffffffbd199110-0xffffffffbd199160	print_type_x32
0xffffffffbd199160-0xffffffffbd1991b0	print_type_x64

But not always:

0xffffffffbd1997b0-0xffffffffbd1997c0	fetch_kernel_stack_address (kernel/trace/trace_probe.c)
0xffffffffbd1c57f0-0xffffffffbd1c58b0	__context_tracking_enter   (kernel/context_tracking.c)

Signed-off-by: Li Bin <huawei.libin@...wei.com>
Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Wang Nan <wangnan0@...wei.com>
Cc: zhangmengting@...wei.com
Fixes: 9aaf5a5f479b ("perf probe: Check kprobes blacklist when adding new events")
Link: http://lkml.kernel.org/r/1504011443-7269-1-git-send-email-huawei.libin@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/probe-event.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index d7cd114..b7aaf9b 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2395,7 +2395,7 @@ kprobe_blacklist__find_by_address(struct list_head *blacklist,
 	struct kprobe_blacklist_node *node;
 
 	list_for_each_entry(node, blacklist, list) {
-		if (node->start <= address && address <= node->end)
+		if (node->start <= address && address < node->end)
 			return node;
 	}