The following commit has been merged into the locking/core branch of tip:
Commit-ID: 3635ad878242487fc3e8165d0329aedb118e4608
Gitweb: https://git.kernel.org/tip/3635ad878242487fc3e8165d0329aedb118e4608
Author: Marco Elver <elver@google.com>
AuthorDate: Fri, 19 Dec 2025 16:40:15 +01:00
Committer: Peter Zijlstra <peterz@infradead.org>
CommitterDate: Mon, 05 Jan 2026 16:43:34 +01:00
compiler: Let data_race() imply disabled context analysis
Many patterns that involve data-racy accesses often deliberately ignore
normal synchronization rules to avoid taking a lock.
If we have a lock-guarded variable on which we do a lock-less data-racy
access, rather than having to write context_unsafe(data_race(..)),
simply make the data_race(..) macro imply context-unsafety. The
data_race() macro already denotes the intent that something subtly
unsafe is about to happen, so it should be clear enough as-is.
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251219154418.3592607-27-elver@google.com
---
include/linux/compiler.h | 2 ++
lib/test_context-analysis.c | 2 ++
2 files changed, 4 insertions(+)
diff --git a/include/linux/compiler.h b/include/linux/compiler.h
index 04487c9..110b28d 100644
--- a/include/linux/compiler.h
+++ b/include/linux/compiler.h
@@ -190,7 +190,9 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
#define data_race(expr) \
({ \
__kcsan_disable_current(); \
+ disable_context_analysis(); \
auto __v = (expr); \
+ enable_context_analysis(); \
__kcsan_enable_current(); \
__v; \
})
diff --git a/lib/test_context-analysis.c b/lib/test_context-analysis.c
index 2dc4044..1c5a381 100644
--- a/lib/test_context-analysis.c
+++ b/lib/test_context-analysis.c
@@ -92,6 +92,8 @@ static void __used test_raw_spinlock_trylock_extra(struct test_raw_spinlock_data
{
unsigned long flags;
+ data_race(d->counter++); /* no warning */
+
if (raw_spin_trylock_irq(&d->lock)) {
d->counter++;
raw_spin_unlock_irq(&d->lock);