LKML Archive on lore.kernel.org
 help / color / Atom feed
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
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


  parent reply index

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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200624190307.15191-3-paulmck@kernel.org \
    --to=paulmck@kernel.org \
    --cc=andreyknvl@google.com \
    --cc=boqun.feng@gmail.com \
    --cc=cai@lca.pw \
    --cc=dvyukov@google.com \
    --cc=elver@google.com \
    --cc=glider@google.com \
    --cc=kasan-dev@googlegroups.com \
    --cc=kernel-team@fb.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

LKML Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/lkml/0 lkml/git/0.git
	git clone --mirror https://lore.kernel.org/lkml/1 lkml/git/1.git
	git clone --mirror https://lore.kernel.org/lkml/2 lkml/git/2.git
	git clone --mirror https://lore.kernel.org/lkml/3 lkml/git/3.git
	git clone --mirror https://lore.kernel.org/lkml/4 lkml/git/4.git
	git clone --mirror https://lore.kernel.org/lkml/5 lkml/git/5.git
	git clone --mirror https://lore.kernel.org/lkml/6 lkml/git/6.git
	git clone --mirror https://lore.kernel.org/lkml/7 lkml/git/7.git
	git clone --mirror https://lore.kernel.org/lkml/8 lkml/git/8.git
	git clone --mirror https://lore.kernel.org/lkml/9 lkml/git/9.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 lkml lkml/ https://lore.kernel.org/lkml \
		linux-kernel@vger.kernel.org
	public-inbox-index lkml

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-kernel


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git