From: paulmck@kernel.org
To: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
kernel-team@fb.com, mingo@kernel.org
Cc: elver@google.com, andreyknvl@google.com, glider@google.com,
dvyukov@google.com, cai@lca.pw, boqun.feng@gmail.com,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH kcsan 3/3] kcsan: Disable branch tracing in core runtime
Date: Wed, 24 Jun 2020 12:03:07 -0700 [thread overview]
Message-ID: <20200624190307.15191-3-paulmck@kernel.org> (raw)
In-Reply-To: <20200624190236.GA6603@paulmck-ThinkPad-P72>
From: Marco Elver <elver@google.com>
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 <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
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
next prev parent reply other threads:[~2020-06-24 19:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 0:43 [PATCH kcsan 0/10] KCSAN updates for v5.9 Paul E. McKenney
2020-06-23 6:31 ` Marco Elver
2020-06-23 13:43 ` Paul E. McKenney
2020-06-23 15:06 ` Marco Elver
2020-06-23 16:31 ` Paul E. McKenney
2020-06-24 19:02 ` Paul E. McKenney
2020-06-24 19:03 ` [PATCH kcsan 1/3] kcsan: Re-add GCC as a supported compiler paulmck
2020-06-24 19:03 ` [PATCH kcsan 2/3] kcsan: Simplify compiler flags paulmck
2020-06-24 19:03 ` paulmck [this message]
2020-06-24 20:08 ` [PATCH kcsan 0/10] KCSAN updates for v5.9 Paul E. McKenney
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