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>,
Will Deacon <will@kernel.org>
Subject: [PATCH v4 tip/core/rcu 13/15] kcsan: Change data_race() to no longer require marking racing accesses
Date: Wed, 15 Apr 2020 11:34:09 -0700 [thread overview]
Message-ID: <20200415183411.12368-13-paulmck@kernel.org> (raw)
In-Reply-To: <20200415183343.GA12265@paulmck-ThinkPad-P72>
From: Marco Elver <elver@google.com>
Thus far, accesses marked with data_race() would still require the
racing access to be marked in some way (be it with READ_ONCE(),
WRITE_ONCE(), or data_race() itself), as otherwise KCSAN would still
report a data race. This requirement, however, seems to be unintuitive,
and some valid use-cases demand *not* marking other accesses, as it
might hide more serious bugs (e.g. diagnostic reads).
Therefore, this commit changes data_race() to no longer require marking
racing accesses (although it's still recommended if possible).
The alternative would have been introducing another variant of
data_race(), however, since usage of data_race() already needs to be
carefully reasoned about, distinguishing between these cases likely adds
more complexity in the wrong place.
Link: https://lkml.kernel.org/r/20200331131002.GA30975@willie-the-truck
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Will Deacon <will@kernel.org>
Cc: Qian Cai <cai@lca.pw>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
include/linux/compiler.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index f504ede..1729bd1 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -326,9 +326,9 @@ unsigned long read_word_at_a_time(const void *addr)
#define data_race(expr) \
({ \
typeof(({ expr; })) __val; \
- kcsan_nestable_atomic_begin(); \
+ kcsan_disable_current(); \
__val = ({ expr; }); \
- kcsan_nestable_atomic_end(); \
+ kcsan_enable_current(); \
__val; \
})
#else
--
2.9.5
next prev parent reply other threads:[~2020-04-15 19:08 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-15 18:33 [PATCH kcsan 0/15] KCSAN updates for v5.8 Paul E. McKenney
2020-04-15 18:33 ` [PATCH v4 tip/core/rcu 01/15] kcsan: Add option to allow watcher interruptions paulmck
2020-04-15 18:33 ` [PATCH v4 tip/core/rcu 02/15] kcsan: Add option for verbose reporting paulmck
2020-04-15 18:33 ` [PATCH v4 tip/core/rcu 03/15] kcsan: Add current->state to implicitly atomic accesses paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 04/15] kcsan: Fix a typo in a comment paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 05/15] kcsan: Update Documentation/dev-tools/kcsan.rst paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 06/15] kcsan: Update API documentation in kcsan-checks.h paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 07/15] kcsan: Introduce report access_info and other_info paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 08/15] kcsan: Avoid blocking producers in prepare_report() paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 09/15] kcsan: Add support for scoped accesses paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 10/15] objtool, kcsan: Add explicit check functions to uaccess whitelist paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 11/15] kcsan: Introduce scoped ASSERT_EXCLUSIVE macros paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 12/15] kcsan: Move kcsan_{disable,enable}_current() to kcsan-checks.h paulmck
2020-04-15 18:34 ` paulmck [this message]
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 14/15] kcsan: Fix function matching in report paulmck
2020-04-15 18:34 ` [PATCH v4 tip/core/rcu 15/15] kcsan: Make reporting aware of KCSAN tests paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 01/10] tools/memory-model: Add recent references paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 02/10] tools/memory-model: Fix "conflict" definition paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 03/10] Documentation: LKMM: Move MP+onceassign+derefonce to new litmus-tests/rcu/ paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 04/10] Documentation: LKMM: Add litmus test for RCU GP guarantee where updater frees object paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 05/10] Documentation: LKMM: Add litmus test for RCU GP guarantee where reader stores paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 06/10] MAINTAINERS: Update maintainers for new Documentaion/litmus-tests/ paulmck
2020-04-15 21:39 ` Joe Perches
2020-04-16 0:17 ` Paul E. McKenney
2020-04-16 1:46 ` Joe Perches
2020-04-16 10:07 ` Paul E. McKenney
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 07/10] tools/memory-model: Add an exception for limitations on _unless() family paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 08/10] Documentation/litmus-tests: Introduce atomic directory paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 09/10] Documentation/litmus-tests/atomic: Add a test for atomic_set() paulmck
2020-04-15 18:49 ` [PATCH lkmm tip/core/rcu 10/10] Documentation/litmus-tests/atomic: Add a test for smp_mb__after_atomic() paulmck
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