linux-kernel - [PATCH AUTOSEL for 3.18 007/101] perf tests: Decompress kernel module before objdump

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Message-ID: <20180409003505.164715-7-alexander.levin@microsoft.com>
Date:   Mon, 9 Apr 2018 00:35:15 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "stable@...r.kernel.org" <stable@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     Namhyung Kim <namhyung@...nel.org>,
        David Ahern <dsahern@...il.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Wang Nan <wangnan0@...wei.com>,
        "kernel-team@....com" <kernel-team@....com>,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 3.18 007/101] perf tests: Decompress kernel module
 before objdump

From: Namhyung Kim <namhyung@...nel.org>

[ Upstream commit 94df1040b1e6aacd8dec0ba3c61d7e77cd695f26 ]

If a kernel modules is compressed, it should be decompressed before
running objdump to parse binary data correctly.  This fixes a failure of
object code reading test for me.

Signed-off-by: Namhyung Kim <namhyung@...nel.org>
Acked-by: Adrian Hunter <adrian.hunter@...el.com>
Acked-by: Jiri Olsa <jolsa@...nel.org>
Cc: David Ahern <dsahern@...il.com>
Cc: Peter Zijlstra <a.p.zijlstra@...llo.nl>
Cc: Wang Nan <wangnan0@...wei.com>
Cc: kernel-team@....com
Link: http://lkml.kernel.org/r/20170608073109.30699-8-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 tools/perf/tests/code-reading.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c
index 67f2d6323558..28dfd1f7f776 100644
--- a/tools/perf/tests/code-reading.c
+++ b/tools/perf/tests/code-reading.c
@@ -141,6 +141,8 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
 	unsigned char buf2[BUFSZ];
 	size_t ret_len;
 	u64 objdump_addr;
+	const char *objdump_name;
+	char decomp_name[KMOD_DECOMP_LEN];
 	int ret;
 
 	pr_debug("Reading object code for memory address: %#"PRIx64"\n", addr);
@@ -202,9 +204,25 @@ static int read_object_code(u64 addr, size_t len, u8 cpumode,
 		state->done[state->done_cnt++] = al.map->start;
 	}
 
+	objdump_name = al.map->dso->long_name;
+	if (dso__needs_decompress(al.map->dso)) {
+		if (dso__decompress_kmodule_path(al.map->dso, objdump_name,
+						 decomp_name,
+						 sizeof(decomp_name)) < 0) {
+			pr_debug("decompression failed\n");
+			return -1;
+		}
+
+		objdump_name = decomp_name;
+	}
+
 	/* Read the object code using objdump */
 	objdump_addr = map__rip_2objdump(al.map, al.addr);
-	ret = read_via_objdump(al.map->dso->long_name, objdump_addr, buf2, len);
+	ret = read_via_objdump(objdump_name, objdump_addr, buf2, len);
+
+	if (dso__needs_decompress(al.map->dso))
+		unlink(objdump_name);
+
 	if (ret > 0) {
 		/*
 		 * The kernel maps are inaccurate - assume objdump is right in
-- 
2.15.1