kcsan: Show full access type in report
This commit adds access-type information to KCSAN's reports as follows: "read", "read (marked)", "write", and "write (marked)". Suggested-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Marco Elver <elver@google.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
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5c36142574
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@ -255,7 +255,7 @@ static inline unsigned int get_delay(void)
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static noinline void kcsan_found_watchpoint(const volatile void *ptr,
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size_t size,
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bool is_write,
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int type,
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atomic_long_t *watchpoint,
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long encoded_watchpoint)
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{
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@ -276,7 +276,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr,
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flags = user_access_save();
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if (consumed) {
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kcsan_report(ptr, size, is_write, true, raw_smp_processor_id(),
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kcsan_report(ptr, size, type, true, raw_smp_processor_id(),
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KCSAN_REPORT_CONSUMED_WATCHPOINT);
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} else {
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/*
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@ -292,8 +292,9 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr,
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}
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static noinline void
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kcsan_setup_watchpoint(const volatile void *ptr, size_t size, bool is_write)
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kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
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{
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const bool is_write = (type & KCSAN_ACCESS_WRITE) != 0;
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atomic_long_t *watchpoint;
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union {
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u8 _1;
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@ -415,13 +416,13 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, bool is_write)
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* No need to increment 'data_races' counter, as the racing
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* thread already did.
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*/
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kcsan_report(ptr, size, is_write, size > 8 || value_change,
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kcsan_report(ptr, size, type, size > 8 || value_change,
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smp_processor_id(), KCSAN_REPORT_RACE_SIGNAL);
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} else if (value_change) {
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/* Inferring a race, since the value should not have changed. */
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kcsan_counter_inc(KCSAN_COUNTER_RACES_UNKNOWN_ORIGIN);
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if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN))
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kcsan_report(ptr, size, is_write, true,
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kcsan_report(ptr, size, type, true,
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smp_processor_id(),
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KCSAN_REPORT_RACE_UNKNOWN_ORIGIN);
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}
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@ -455,10 +456,10 @@ static __always_inline void check_access(const volatile void *ptr, size_t size,
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*/
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if (unlikely(watchpoint != NULL))
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kcsan_found_watchpoint(ptr, size, is_write, watchpoint,
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kcsan_found_watchpoint(ptr, size, type, watchpoint,
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encoded_watchpoint);
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else if (unlikely(should_watch(ptr, type)))
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kcsan_setup_watchpoint(ptr, size, is_write);
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kcsan_setup_watchpoint(ptr, size, type);
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}
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/* === Public interface ===================================================== */
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@ -103,7 +103,7 @@ enum kcsan_report_type {
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/*
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* Print a race report from thread that encountered the race.
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*/
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extern void kcsan_report(const volatile void *ptr, size_t size, bool is_write,
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extern void kcsan_report(const volatile void *ptr, size_t size, int access_type,
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bool value_change, int cpu_id, enum kcsan_report_type type);
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#endif /* _KERNEL_KCSAN_KCSAN_H */
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@ -24,7 +24,7 @@
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static struct {
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const volatile void *ptr;
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size_t size;
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bool is_write;
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int access_type;
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int task_pid;
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int cpu_id;
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unsigned long stack_entries[NUM_STACK_ENTRIES];
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@ -41,8 +41,10 @@ static DEFINE_SPINLOCK(report_lock);
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* Special rules to skip reporting.
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*/
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static bool
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skip_report(bool is_write, bool value_change, unsigned long top_frame)
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skip_report(int access_type, bool value_change, unsigned long top_frame)
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{
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const bool is_write = (access_type & KCSAN_ACCESS_WRITE) != 0;
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if (IS_ENABLED(CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY) && is_write &&
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!value_change) {
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/*
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@ -63,9 +65,20 @@ skip_report(bool is_write, bool value_change, unsigned long top_frame)
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return kcsan_skip_report_debugfs(top_frame);
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}
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static inline const char *get_access_type(bool is_write)
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static const char *get_access_type(int type)
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{
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return is_write ? "write" : "read";
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switch (type) {
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case 0:
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return "read";
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case KCSAN_ACCESS_ATOMIC:
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return "read (marked)";
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case KCSAN_ACCESS_WRITE:
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return "write";
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case KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ATOMIC:
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return "write (marked)";
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default:
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BUG();
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}
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}
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/* Return thread description: in task or interrupt. */
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@ -112,7 +125,7 @@ static int sym_strcmp(void *addr1, void *addr2)
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/*
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* Returns true if a report was generated, false otherwise.
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*/
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static bool print_report(const volatile void *ptr, size_t size, bool is_write,
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static bool print_report(const volatile void *ptr, size_t size, int access_type,
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bool value_change, int cpu_id,
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enum kcsan_report_type type)
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{
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@ -124,7 +137,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write,
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/*
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* Must check report filter rules before starting to print.
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*/
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if (skip_report(is_write, true, stack_entries[skipnr]))
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if (skip_report(access_type, true, stack_entries[skipnr]))
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return false;
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if (type == KCSAN_REPORT_RACE_SIGNAL) {
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@ -132,7 +145,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write,
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other_info.num_stack_entries);
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/* @value_change is only known for the other thread */
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if (skip_report(other_info.is_write, value_change,
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if (skip_report(other_info.access_type, value_change,
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other_info.stack_entries[other_skipnr]))
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return false;
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}
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@ -170,7 +183,7 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write,
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switch (type) {
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case KCSAN_REPORT_RACE_SIGNAL:
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pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n",
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get_access_type(other_info.is_write), other_info.ptr,
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get_access_type(other_info.access_type), other_info.ptr,
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other_info.size, get_thread_desc(other_info.task_pid),
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other_info.cpu_id);
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@ -181,14 +194,14 @@ static bool print_report(const volatile void *ptr, size_t size, bool is_write,
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pr_err("\n");
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pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n",
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get_access_type(is_write), ptr, size,
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get_access_type(access_type), ptr, size,
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get_thread_desc(in_task() ? task_pid_nr(current) : -1),
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cpu_id);
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break;
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case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN:
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pr_err("race at unknown origin, with %s to 0x%px of %zu bytes by %s on cpu %i:\n",
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get_access_type(is_write), ptr, size,
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get_access_type(access_type), ptr, size,
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get_thread_desc(in_task() ? task_pid_nr(current) : -1),
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cpu_id);
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break;
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@ -223,7 +236,7 @@ static void release_report(unsigned long *flags, enum kcsan_report_type type)
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* required for the report type, simply acquires report_lock and returns true.
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*/
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static bool prepare_report(unsigned long *flags, const volatile void *ptr,
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size_t size, bool is_write, int cpu_id,
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size_t size, int access_type, int cpu_id,
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enum kcsan_report_type type)
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{
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if (type != KCSAN_REPORT_CONSUMED_WATCHPOINT &&
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@ -243,7 +256,7 @@ retry:
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other_info.ptr = ptr;
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other_info.size = size;
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other_info.is_write = is_write;
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other_info.access_type = access_type;
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other_info.task_pid = in_task() ? task_pid_nr(current) : -1;
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other_info.cpu_id = cpu_id;
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other_info.num_stack_entries = stack_trace_save(other_info.stack_entries, NUM_STACK_ENTRIES, 1);
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@ -302,14 +315,14 @@ retry:
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goto retry;
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}
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void kcsan_report(const volatile void *ptr, size_t size, bool is_write,
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void kcsan_report(const volatile void *ptr, size_t size, int access_type,
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bool value_change, int cpu_id, enum kcsan_report_type type)
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{
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unsigned long flags = 0;
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kcsan_disable_current();
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if (prepare_report(&flags, ptr, size, is_write, cpu_id, type)) {
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if (print_report(ptr, size, is_write, value_change, cpu_id, type) && panic_on_warn)
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if (prepare_report(&flags, ptr, size, access_type, cpu_id, type)) {
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if (print_report(ptr, size, access_type, value_change, cpu_id, type) && panic_on_warn)
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panic("panic_on_warn set ...\n");
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release_report(&flags, type);
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