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From: Arnd Bergmann <arnd@kernel.org>
To: Josh Poimboeuf <jpoimboe@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Alexander Potapenko <glider@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Marco Elver <elver@google.com>
Cc: kasan-dev@googlegroups.com, Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <ryabinin.a.a@gmail.com>,
	Vincenzo Frascino <vincenzo.frascino@arm.com>,
	Andrey Konovalov <andreyknvl@gmail.com>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH 2/4] kmsan: disable ftrace in kmsan core code
Date: Wed,  8 Feb 2023 17:39:56 +0100	[thread overview]
Message-ID: <20230208164011.2287122-2-arnd@kernel.org> (raw)
In-Reply-To: <20230208164011.2287122-1-arnd@kernel.org>

From: Arnd Bergmann <arnd@arndb.de>

objtool warns about some suspicous code inside of kmsan:

vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_n+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_n+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_1+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_1+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_2+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_2+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_4+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_4+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_load_8+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_metadata_ptr_for_store_8+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_instrument_asm_store+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_chain_origin+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_poison_alloca+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_warning+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: __msan_get_context_state+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: kmsan_copy_to_user+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: kmsan_unpoison_memory+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: kmsan_unpoison_entry_regs+0x4: call to __fentry__() with UACCESS enabled
vmlinux.o: warning: objtool: kmsan_report+0x4: call to __fentry__() with UACCESS enabled

Similar code already exists in kasan, which avoids this by skipping
ftrace annotations, so do the same thing here.

Fixes: f80be4571b19 ("kmsan: add KMSAN runtime core")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 mm/kmsan/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/mm/kmsan/Makefile b/mm/kmsan/Makefile
index 98eab2856626..389fd767a11f 100644
--- a/mm/kmsan/Makefile
+++ b/mm/kmsan/Makefile
@@ -16,6 +16,14 @@ CC_FLAGS_KMSAN_RUNTIME += -DDISABLE_BRANCH_PROFILING
 
 CFLAGS_REMOVE.o = $(CC_FLAGS_FTRACE)
 
+# Disable ftrace to avoid recursion.
+CFLAGS_REMOVE_core.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_hooks.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_init.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_instrumentation.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE)
+CFLAGS_REMOVE_shadow.o = $(CC_FLAGS_FTRACE)
+
 CFLAGS_core.o := $(CC_FLAGS_KMSAN_RUNTIME)
 CFLAGS_hooks.o := $(CC_FLAGS_KMSAN_RUNTIME)
 CFLAGS_init.o := $(CC_FLAGS_KMSAN_RUNTIME)
-- 
2.39.1



  reply	other threads:[~2023-02-08 16:40 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-08 16:39 [PATCH 1/4] kasan: mark addr_has_metadata __always_inline Arnd Bergmann
2023-02-08 16:39 ` Arnd Bergmann [this message]
2023-02-08 17:00   ` [PATCH 2/4] kmsan: disable ftrace in kmsan core code Marco Elver
2023-02-08 19:31     ` Arnd Bergmann
2023-02-09 15:42       ` Alexander Potapenko
2023-02-08 17:01 ` [PATCH 1/4] kasan: mark addr_has_metadata __always_inline Marco Elver
2023-02-08 18:10 ` Peter Zijlstra
2023-02-09 19:26 ` Josh Poimboeuf
2023-02-09 22:21 ` Andrey Konovalov

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