linux-kernel - [PATCH V4 09/17] perf thread: Add a knob for LBR stitch approach

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20200319202517.23423-10-kan.liang@linux.intel.com>
Date:   Thu, 19 Mar 2020 13:25:09 -0700
From:   kan.liang@...ux.intel.com
To:     acme@...nel.org, jolsa@...hat.com, peterz@...radead.org,
        mingo@...hat.com, linux-kernel@...r.kernel.org
Cc:     namhyung@...nel.org, adrian.hunter@...el.com,
        mathieu.poirier@...aro.org, ravi.bangoria@...ux.ibm.com,
        alexey.budankov@...ux.intel.com, vitaly.slobodskoy@...el.com,
        pavel.gerasimov@...el.com, mpe@...erman.id.au, eranian@...gle.com,
        ak@...ux.intel.com, Kan Liang <kan.liang@...ux.intel.com>
Subject: [PATCH V4 09/17] perf thread: Add a knob for LBR stitch approach

From: Kan Liang <kan.liang@...ux.intel.com>

The LBR stitch approach should be disabled by default. Because
- The stitching approach base on LBR call stack technology. The known
limitations of LBR call stack technology still apply to the approach,
e.g. Exception handing such as setjmp/longjmp will have calls/returns
not match.
- This approach is not full proof. There can be cases where it creates
incorrect call stacks from incorrect matches. There is no attempt to
validate any matches in another way.

The 'lbr_stitch_enable' is used to indicate whether enable LBR stitch
approach, which is disabled by default. The following patch will
introduce a new option for each tools to enable the LBR stitch
approach.

Reviewed-by: Andi Kleen <ak@...ux.intel.com>
Signed-off-by: Kan Liang <kan.liang@...ux.intel.com>
---
 tools/perf/util/thread.c | 1 +
 tools/perf/util/thread.h | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 28b719388028..1f080db23615 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -47,6 +47,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 		thread->tid = tid;
 		thread->ppid = -1;
 		thread->cpu = -1;
+		thread->lbr_stitch_enable = false;
 		INIT_LIST_HEAD(&thread->namespaces_list);
 		INIT_LIST_HEAD(&thread->comm_list);
 		init_rwsem(&thread->namespaces_lock);
diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 20b96b5d1f15..95294050cff2 100644
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -46,6 +46,9 @@ struct thread {
 	struct srccode_state	srccode_state;
 	bool			filter;
 	int			filter_entry_depth;
+
+	/* LBR call stack stitch */
+	bool			lbr_stitch_enable;
 };
 
 struct machine;
-- 
2.17.1