1 // SPDX-License-Identifier: GPL-2.0
24  * Max. number of stack entries to show in the report.
40  * up the watchpoint, which then prints the complete report atomically.
69  * as we have watchpoints (upper bound on concurrent races to report).
71 static struct other_info other_infos[CONFIG_KCSAN_NUM_WATCHPOINTS + NUM_SLOTS-1];
95  * Therefore, we use a fixed-size array, which at most will occupy a page. This
108  * Spinlock serializing report generation, and access to @other_infos. Although
109  * it could make sense to have a finer-grained locking story for @other_infos,
110  * report generation needs to be serialized either way, so not much is gained.
116  * been reported since (now - KCSAN_REPORT_ONCE_IN_MS).
129 	invalid_before = jiffies - msecs_to_jiffies(CONFIG_KCSAN_REPORT_ONCE_IN_MS);  in rate_limit_report()
131 	/* Check if a matching race report exists. */  in rate_limit_report()
141 		if (time_before(rt->time, use_entry->time))  in rate_limit_report()
148 		if (rt->time == 0)  in rate_limit_report()
152 		if (time_before(rt->time, invalid_before))  in rate_limit_report()
156 		if ((rt->frame1 == frame1 && rt->frame2 == frame2) ||  in rate_limit_report()
157 		    (rt->frame1 == frame2 && rt->frame2 == frame1))  in rate_limit_report()
161 	use_entry->time = jiffies;  in rate_limit_report()
162 	use_entry->frame1 = frame1;  in rate_limit_report()
163 	use_entry->frame2 = frame2;  in rate_limit_report()
181 	 * 1. read watchpoint, conflicting write (value_change==TRUE): report;  in skip_report()
183 	 * 3. write watchpoint, conflicting write (value_change==TRUE): report;  in skip_report()
186 	 * 6. write watchpoint, conflicting read (value_change==TRUE): report;  in skip_report()
188 	 * Cases 1-4 are intuitive and expected; case 5 ensures we do not report  in skip_report()
198 		 * We opt-out of this filter for certain functions at request of  in skip_report()
239 		return "read-write";  in get_access_type()
241 		return "read-write (marked)";  in get_access_type()
251 		return "read-write (reordered)";  in get_access_type()
253 		return "read-write (marked, reordered)";  in get_access_type()
261 	return (type & KCSAN_ACCESS_ASSERT) != 0 ? "assert: race" : "data-race";  in get_bug_type()
267 	if (task_id != -1) {  in get_thread_desc()
276 /* Helper to skip KCSAN-related functions in stack-trace. */
300 		 * No match for runtime functions -- @skip entries to skip to  in get_stack_skipnr()
323 		target_func = ip - offset;  in replace_stack_entry()
332 		func -= offset;  in replace_stack_entry()
372 		pr_err("  |\n  +-> reordered to: %pS\n", (void *)reordered_to);  in print_stack_trace()
391 			 u64 old, u64 new, u64 mask)  in print_report()  argument
396 	int skipnr = sanitize_stack_entries(stack_entries, num_stack_entries, ai->ip, &reordered_to);  in print_report()
403 	 * Must check report filter rules before starting to print.  in print_report()
409 		other_skipnr = sanitize_stack_entries(other_info->stack_entries,  in print_report()
410 						      other_info->num_stack_entries,  in print_report()
411 						      other_info->ai.ip, &other_reordered_to);  in print_report()
412 		other_frame = other_info->stack_entries[other_skipnr];  in print_report()
422 	/* Print report header. */  in print_report()
433 		       get_bug_type(ai->access_type | other_info->ai.access_type),  in print_report()
437 		pr_err("BUG: KCSAN: %s in %pS\n", get_bug_type(ai->access_type),  in print_report()
446 		       get_access_type(other_info->ai.access_type), other_info->ai.ptr,  in print_report()
447 		       other_info->ai.size, get_thread_desc(other_info->ai.task_pid),  in print_report()
448 		       other_info->ai.cpu_id);  in print_report()
451 		print_stack_trace(other_info->stack_entries + other_skipnr,  in print_report()
452 				  other_info->num_stack_entries - other_skipnr,  in print_report()
455 			print_verbose_info(other_info->task);  in print_report()
459 		       get_access_type(ai->access_type), ai->ptr, ai->size,  in print_report()
460 		       get_thread_desc(ai->task_pid), ai->cpu_id);  in print_report()
463 		       get_access_type(ai->access_type), ai->ptr, ai->size,  in print_report()
464 		       get_thread_desc(ai->task_pid), ai->cpu_id);  in print_report()
467 	print_stack_trace(stack_entries + skipnr, num_stack_entries - skipnr, reordered_to);  in print_report()
472 	if (ai->size <= 8) {  in print_report()
473 		int hex_len = ai->size * 2;  in print_report()
476 		if (mask)  in print_report()
477 			diff &= mask;  in print_report()
480 			pr_err("value changed: 0x%0*llx -> 0x%0*llx\n",  in print_report()
482 			if (mask) {  in print_report()
483 				pr_err(" bits changed: 0x%0*llx with mask 0x%0*llx\n",  in print_report()
484 				       hex_len, diff, hex_len, mask);  in print_report()
489 	/* Print report footer. */  in print_report()
502 	 * 0-sized accesses.  in release_report()
504 	other_info->ai.size = 0;  in release_report()
509  * Sets @other_info->task and awaits consumption of @other_info.
519 	 * We may be instrumenting a code-path where current->state is already  in set_other_info_task_blocking()
533 	other_info->task = current;  in set_other_info_task_blocking()
546 		 * determine if sleeping here is permitted -- see in_atomic().  in set_other_info_task_blocking()
551 		if (timeout-- < 0) {  in set_other_info_task_blocking()
553 			 * Abort. Reset @other_info->task to NULL, since it  in set_other_info_task_blocking()
558 			other_info->task = NULL;  in set_other_info_task_blocking()
565 	} while (other_info->ai.size && other_info->ai.ptr == ai->ptr &&  in set_other_info_task_blocking()
566 		 other_info->task == current);  in set_other_info_task_blocking()
580 	 * there is a one-to-one mapping to watchpoint slots (@watchpoints in  in prepare_report_producer()
587 	 * To check this property holds, size should never be non-zero here,  in prepare_report_producer()
591 	WARN_ON(other_info->ai.size);  in prepare_report_producer()
593 	other_info->ai = *ai;  in prepare_report_producer()
594 	other_info->num_stack_entries = stack_trace_save(other_info->stack_entries, NUM_STACK_ENTRIES, 2);  in prepare_report_producer()
609 	while (!other_info->ai.size) { /* Await valid @other_info. */  in prepare_report_consumer()
616 …if (WARN_ON(!matching_access((unsigned long)other_info->ai.ptr & WATCHPOINT_ADDR_MASK, other_info-…  in prepare_report_consumer()
617 				     (unsigned long)ai->ptr & WATCHPOINT_ADDR_MASK, ai->size)))  in prepare_report_consumer()
620 	if (!matching_access((unsigned long)other_info->ai.ptr, other_info->ai.size,  in prepare_report_consumer()
621 			     (unsigned long)ai->ptr, ai->size)) {  in prepare_report_consumer()
644 		.task_pid	= in_task() ? task_pid_nr(current) : -1,  in prepare_access_info()
668 			       int watchpoint_idx, u64 old, u64 new, u64 mask)  in kcsan_report_known_origin()  argument
678 	 * called in print_report() is scheduler-safe, accept the risk, and just  in kcsan_report_known_origin()
679 	 * get our message out. As such, also disable lockdep to hide the  in kcsan_report_known_origin()
687 	 * Never report if value_change is FALSE, only when it is  in kcsan_report_known_origin()
692 		print_report(value_change, &ai, other_info, old, new, mask);  in kcsan_report_known_origin()
701 				 unsigned long ip, u64 old, u64 new, u64 mask)  in kcsan_report_unknown_origin()  argument
710 	print_report(KCSAN_VALUE_CHANGE_TRUE, &ai, NULL, old, new, mask);  in kcsan_report_unknown_origin()