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McKenney" Subject: [PATCH kcsan 3/3] kcsan: Disable branch tracing in core runtime Date: Wed, 24 Jun 2020 12:03:07 -0700 Message-Id: <20200624190307.15191-3-paulmck@kernel.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20200624190236.GA6603@paulmck-ThinkPad-P72> References: <20200624190236.GA6603@paulmck-ThinkPad-P72> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Marco Elver Disable branch tracing in core KCSAN runtime if branches are being traced (TRACE_BRANCH_PROFILING). This it to avoid its performance impact, but also avoid recursion in case KCSAN is enabled for the branch tracing runtime. The latter had already been a problem for KASAN: https://lore.kernel.org/lkml/CANpmjNOeXmD5E3O50Z3MjkiuCYaYOPyi+1rq=GZvEKwBvLR0Ug@mail.gmail.com/ Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney --- kernel/kcsan/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile index fea064a..65ca553 100644 --- a/kernel/kcsan/Makefile +++ b/kernel/kcsan/Makefile @@ -8,7 +8,7 @@ CFLAGS_REMOVE_debugfs.o = $(CC_FLAGS_FTRACE) CFLAGS_REMOVE_report.o = $(CC_FLAGS_FTRACE) CFLAGS_core.o := $(call cc-option,-fno-conserve-stack) \ - -fno-stack-protector + -fno-stack-protector -DDISABLE_BRANCH_PROFILING obj-y := core.o debugfs.o report.o obj-$(CONFIG_KCSAN_SELFTEST) += selftest.o -- 2.9.5