Re: FAILED: patch "[PATCH] perf probe: Fix ppc64 'perf probe add events failed' case" failed to apply to 5.4-stable tree

[Sudip Mukherjee <sudipm.mukherjee@gmail.com>]

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Hi Greg,

On Mon, Jan 24, 2022 at 02:33:09PM +0100, gregkh@linuxfoundation.org wrote:
> 
> The patch below does not apply to the 5.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@vger.kernel.org>.

Here is the backport, will also apply to 4.19-stable tree.

--
Regards
Sudip

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From ff3e8777c4a2aef9e680088fcc292ee8ace17f57 Mon Sep 17 00:00:00 2001
From: Zechuan Chen <chenzechuan1@huawei.com>
Date: Tue, 28 Dec 2021 19:13:38 +0800
Subject: [PATCH] perf probe: Fix ppc64 'perf probe add events failed' case

commit 4624f199327a704dd1069aca1c3cadb8f2a28c6f upstream.

Because of commit bf794bf52a80c627 ("powerpc/kprobes: Fix kallsyms
lookup across powerpc ABIv1 and ABIv2"), in ppc64 ABIv1, our perf
command eliminates the need to use the prefix "." at the symbol name.

But when the command "perf probe -a schedule" is executed on ppc64
ABIv1, it obtains two symbol address information through /proc/kallsyms,
for example:

  cat /proc/kallsyms | grep -w schedule
  c000000000657020 T .schedule
  c000000000d4fdb8 D schedule

The symbol "D schedule" is not a function symbol, and perf will print:
"p:probe/schedule _text+13958584"Failed to write event: Invalid argument

Therefore, when searching symbols from map and adding probe point for
them, a symbol type check is added. If the type of symbol is not a
function, skip it.

Fixes: bf794bf52a80c627 ("powerpc/kprobes: Fix kallsyms lookup across powerpc ABIv1 and ABIv2")
Signed-off-by: Zechuan Chen <chenzechuan1@huawei.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jianlin Lv <Jianlin.Lv@arm.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Yang Jihong <yangjihong1@huawei.com>
Link: https://lore.kernel.org/r/20211228111338.218602-1-chenzechuan1@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
[sudip: adjust context]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
---
 tools/perf/util/probe-event.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 6357ac508ad1..67b7d2af1755 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -2954,6 +2954,9 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev,
 	for (j = 0; j < num_matched_functions; j++) {
 		sym = syms[j];
 
+		if (sym->type != STT_FUNC)
+			continue;
+
 		tev = (*tevs) + ret;
 		tp = &tev->point;
 		if (ret == num_matched_functions) {
-- 
2.30.2