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From:   Ilya Leoshkevich <iii@linux.ibm.com>
To:     Alexander Gordeev <agordeev@linux.ibm.com>,
        Alexander Potapenko <glider@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Christoph Lameter <cl@linux.com>,
        David Rientjes <rientjes@google.com>,
        Heiko Carstens <hca@linux.ibm.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Marco Elver <elver@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Pekka Enberg <penberg@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Vlastimil Babka <vbabka@suse.cz>
Cc:     Christian Borntraeger <borntraeger@linux.ibm.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        Hyeonggon Yoo <42.hyeyoo@gmail.com>,
        kasan-dev@googlegroups.com, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, linux-s390@vger.kernel.org,
        linux-trace-kernel@vger.kernel.org,
        Mark Rutland <mark.rutland@arm.com>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Sven Schnelle <svens@linux.ibm.com>,
        Ilya Leoshkevich <iii@linux.ibm.com>
Subject: [PATCH v2 01/33] ftrace: Unpoison ftrace_regs in ftrace_ops_list_func()
Date:   Tue, 21 Nov 2023 23:00:55 +0100
Message-ID: <20231121220155.1217090-2-iii@linux.ibm.com>
In-Reply-To: <20231121220155.1217090-1-iii@linux.ibm.com>
References: <20231121220155.1217090-1-iii@linux.ibm.com>
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Architectures use assembly code to initialize ftrace_regs and call
ftrace_ops_list_func(). Therefore, from the KMSAN's point of view,
ftrace_regs is poisoned on ftrace_ops_list_func entry(). This causes
KMSAN warnings when running the ftrace testsuite.

Fix by trusting the architecture-specific assembly code and always
unpoisoning ftrace_regs in ftrace_ops_list_func.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 kernel/trace/ftrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 8de8bec5f366..dfb8b26966aa 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -7399,6 +7399,7 @@ __ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 void arch_ftrace_ops_list_func(unsigned long ip, unsigned long parent_ip,
 			       struct ftrace_ops *op, struct ftrace_regs *fregs)
 {
+	kmsan_unpoison_memory(fregs, sizeof(*fregs));
 	__ftrace_ops_list_func(ip, parent_ip, NULL, fregs);
 }
 #else
-- 
2.41.0