[PATCH v4 29/35] kcsan: Enable context analysis

[Marco Elver <elver@google.com>]

Enable context analysis for the KCSAN subsystem.

Signed-off-by: Marco Elver <elver@google.com>
---
v4:
* Rename capability -> context analysis.

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..824f30c93252 100644
--- a/kernel/kcsan/Makefile
+++ b/kernel/kcsan/Makefile
@@ -1,4 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
+CONTEXT_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);
-- 
2.52.0.rc1.455.g30608eb744-goog