linux-kernel - [PATCH v3 29/35] kcsan: Enable capability analysis

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Message-ID: <20250918140451.1289454-30-elver@google.com>
Date: Thu, 18 Sep 2025 15:59:40 +0200
From: Marco Elver <elver@...gle.com>
To: elver@...gle.com, Peter Zijlstra <peterz@...radead.org>, 
	Boqun Feng <boqun.feng@...il.com>, Ingo Molnar <mingo@...nel.org>, Will Deacon <will@...nel.org>
Cc: "David S. Miller" <davem@...emloft.net>, Luc Van Oostenryck <luc.vanoostenryck@...il.com>, 
	"Paul E. McKenney" <paulmck@...nel.org>, Alexander Potapenko <glider@...gle.com>, Arnd Bergmann <arnd@...db.de>, 
	Bart Van Assche <bvanassche@....org>, Bill Wendling <morbo@...gle.com>, Christoph Hellwig <hch@....de>, 
	Dmitry Vyukov <dvyukov@...gle.com>, Eric Dumazet <edumazet@...gle.com>, 
	Frederic Weisbecker <frederic@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, 
	Herbert Xu <herbert@...dor.apana.org.au>, Ian Rogers <irogers@...gle.com>, 
	Jann Horn <jannh@...gle.com>, Joel Fernandes <joelagnelf@...dia.com>, 
	Jonathan Corbet <corbet@....net>, Josh Triplett <josh@...htriplett.org>, 
	Justin Stitt <justinstitt@...gle.com>, Kees Cook <kees@...nel.org>, 
	Kentaro Takeda <takedakn@...data.co.jp>, Lukas Bulwahn <lukas.bulwahn@...il.com>, 
	Mark Rutland <mark.rutland@....com>, Mathieu Desnoyers <mathieu.desnoyers@...icios.com>, 
	Miguel Ojeda <ojeda@...nel.org>, Nathan Chancellor <nathan@...nel.org>, 
	Neeraj Upadhyay <neeraj.upadhyay@...nel.org>, 
	Nick Desaulniers <nick.desaulniers+lkml@...il.com>, Steven Rostedt <rostedt@...dmis.org>, 
	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>, Thomas Gleixner <tglx@...utronix.de>, 
	Thomas Graf <tgraf@...g.ch>, Uladzislau Rezki <urezki@...il.com>, Waiman Long <longman@...hat.com>, 
	kasan-dev@...glegroups.com, linux-crypto@...r.kernel.org, 
	linux-doc@...r.kernel.org, linux-kbuild@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, 
	linux-security-module@...r.kernel.org, linux-sparse@...r.kernel.org, 
	llvm@...ts.linux.dev, rcu@...r.kernel.org
Subject: [PATCH v3 29/35] kcsan: Enable capability analysis

Enable capability analysis for the KCSAN subsystem.

Signed-off-by: Marco Elver <elver@...gle.com>
---
v3:
* New patch.
---
 kernel/kcsan/Makefile |  2 ++
 kernel/kcsan/report.c | 11 ++++++++---
 2 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/kernel/kcsan/Makefile b/kernel/kcsan/Makefile
index a45f3dfc8d14..b088aa01409f 100644
--- a/kernel/kcsan/Makefile
+++ b/kernel/kcsan/Makefile
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
+CAPABILITY_ANALYSIS := y
+
 KCSAN_SANITIZE := n
 KCOV_INSTRUMENT := n
 UBSAN_SANITIZE := n
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
index e95ce7d7a76e..11a48b78f8d1 100644
--- a/kernel/kcsan/report.c
+++ b/kernel/kcsan/report.c
@@ -116,6 +116,7 @@ static DEFINE_RAW_SPINLOCK(report_lock);
  * been reported since (now - KCSAN_REPORT_ONCE_IN_MS).
  */
 static bool rate_limit_report(unsigned long frame1, unsigned long frame2)
+	__must_hold(&report_lock)
 {
 	struct report_time *use_entry = &report_times[0];
 	unsigned long invalid_before;
@@ -366,6 +367,7 @@ static int sym_strcmp(void *addr1, void *addr2)
 
 static void
 print_stack_trace(unsigned long stack_entries[], int num_entries, unsigned long reordered_to)
+	__must_hold(&report_lock)
 {
 	stack_trace_print(stack_entries, num_entries, 0);
 	if (reordered_to)
@@ -373,6 +375,7 @@ print_stack_trace(unsigned long stack_entries[], int num_entries, unsigned long
 }
 
 static void print_verbose_info(struct task_struct *task)
+	__must_hold(&report_lock)
 {
 	if (!task)
 		return;
@@ -389,6 +392,7 @@ static void print_report(enum kcsan_value_change value_change,
 			 const struct access_info *ai,
 			 struct other_info *other_info,
 			 u64 old, u64 new, u64 mask)
+	__must_hold(&report_lock)
 {
 	unsigned long reordered_to = 0;
 	unsigned long stack_entries[NUM_STACK_ENTRIES] = { 0 };
@@ -496,6 +500,7 @@ static void print_report(enum kcsan_value_change value_change,
 }
 
 static void release_report(unsigned long *flags, struct other_info *other_info)
+	__releases(&report_lock)
 {
 	/*
 	 * Use size to denote valid/invalid, since KCSAN entirely ignores
@@ -507,13 +512,11 @@ static void release_report(unsigned long *flags, struct other_info *other_info)
 
 /*
  * Sets @other_info->task and awaits consumption of @other_info.
- *
- * Precondition: report_lock is held.
- * Postcondition: report_lock is held.
  */
 static void set_other_info_task_blocking(unsigned long *flags,
 					 const struct access_info *ai,
 					 struct other_info *other_info)
+	__must_hold(&report_lock)
 {
 	/*
 	 * We may be instrumenting a code-path where current->state is already
@@ -572,6 +575,7 @@ static void set_other_info_task_blocking(unsigned long *flags,
 static void prepare_report_producer(unsigned long *flags,
 				    const struct access_info *ai,
 				    struct other_info *other_info)
+	__must_not_hold(&report_lock)
 {
 	raw_spin_lock_irqsave(&report_lock, *flags);
 
@@ -603,6 +607,7 @@ static void prepare_report_producer(unsigned long *flags,
 static bool prepare_report_consumer(unsigned long *flags,
 				    const struct access_info *ai,
 				    struct other_info *other_info)
+	__cond_acquires(true, &report_lock)
 {
 
 	raw_spin_lock_irqsave(&report_lock, *flags);
-- 
2.51.0.384.g4c02a37b29-goog