Currently kcsan_report() is used to handle three distinct cases: * The caller hit a watchpoint when attempting an access. Some information regarding the caller and access are recorded, but no output is produced. * A caller which previously setup a watchpoint detected that the watchpoint has been hit, and possibly detected a change to the location in memory being watched. This may result in output reporting the interaction between this caller and the caller which hit the watchpoint. * A caller detected a change to a modification to a memory location which wasn't detected by a watchpoint, for which there is no information on the other thread. This may result in output reporting the unexpected change. ... depending on the specific case the caller has distinct pieces of information available, but the prototype of kcsan_report() has to handle all three cases. This means that in some cases we pass redundant information, and in others we don't pass all the information we could pass. This also means that the report code has to demux these three cases. So that we can pass some additional information while also simplifying the callers and report code, add separate kcsan_report_*() functions for the distinct cases, updating callers accordingly. As the watchpoint_idx is unused in the case of kcsan_report_unknown_origin(), this passes a dummy value into kcsan_report(). Subsequent patches will refactor the report code to avoid this. There should be no functional change as a result of this patch.
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| @@ -380,9 +380,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr, · 379 unmodified lines | |||
| 380 | 380 | ||
| 381 | if (consumed) { | 381 | if (consumed) { |
| 382 | kcsan_save_irqtrace(current); | 382 | kcsan_save_irqtrace(current); |
| 383 | kcsan_report(ptr, size, type, KCSAN_VALUE_CHANGE_MAYBE, | 383 | kcsan_report_set_info(ptr, size, type, watchpoint - watchpoints); |
| 384 | KCSAN_REPORT_CONSUMED_WATCHPOINT, | ||
| 385 | watchpoint - watchpoints); | ||
| 386 | kcsan_restore_irqtrace(current); | 384 | kcsan_restore_irqtrace(current); |
| 387 | } else { | 385 | } else { |
| 388 | /* | 386 | /* |
| @@ -558,8 +556,8 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) · 169 unmodified lines | |||
| 558 | if (is_assert && value_change == KCSAN_VALUE_CHANGE_TRUE) | 556 | if (is_assert && value_change == KCSAN_VALUE_CHANGE_TRUE) |
| 559 | atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); | 557 | atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); |
| 560 | 558 | ||
| 561 | kcsan_report(ptr, size, type, value_change, KCSAN_REPORT_RACE_SIGNAL, | 559 | kcsan_report_known_origin(ptr, size, type, value_change, |
| 562 | watchpoint - watchpoints); | 560 | watchpoint - watchpoints); |
| 563 | } else if (value_change == KCSAN_VALUE_CHANGE_TRUE) { | 561 | } else if (value_change == KCSAN_VALUE_CHANGE_TRUE) { |
| 564 | /* Inferring a race, since the value should not have changed. */ | 562 | /* Inferring a race, since the value should not have changed. */ |
| 565 | 563 | ||
| @@ -568,9 +566,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type) · 2 unmodified lines | |||
| 568 | atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); | 566 | atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]); |
| 569 | 567 | ||
| 570 | if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert) | 568 | if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert) |
| 571 | kcsan_report(ptr, size, type, KCSAN_VALUE_CHANGE_TRUE, | 569 | kcsan_report_unknown_origin(ptr, size, type); |
| 572 | KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, | ||
| 573 | watchpoint - watchpoints); | ||
| 574 | } | 570 | } |
| 575 | 571 | ||
| 576 | /* | 572 | /* |
| @@ -136,10 +136,12 @@ enum kcsan_report_type { · 135 unmodified lines | |||
| 136 | }; | 136 | }; |
| 137 | 137 | ||
| 138 | /* | 138 | /* |
| 139 | * Print a race report from thread that encountered the race. | 139 | * Notify the report code that a race occurred. |
| 140 | */ | 140 | */ |
| 141 | extern void kcsan_report(const volatile void *ptr, size_t size, int access_type, | 141 | void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, |
| 142 | enum kcsan_value_change value_change, | 142 | int watchpoint_idx); |
| 143 | enum kcsan_report_type type, int watchpoint_idx); | 143 | void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, |
| 144 | enum kcsan_value_change value_change, int watchpoint_idx); | ||
| 145 | void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type); | ||
| 144 | 146 | ||
| 145 | #endif /* _KERNEL_KCSAN_KCSAN_H */ | 147 | #endif /* _KERNEL_KCSAN_KCSAN_H */ |
| @@ -598,9 +598,9 @@ static noinline bool prepare_report(unsigned long *flags, · 597 unmodified lines | |||
| 598 | } | 598 | } |
| 599 | } | 599 | } |
| 600 | 600 | ||
| 601 | void kcsan_report(const volatile void *ptr, size_t size, int access_type, | 601 | static void kcsan_report(const volatile void *ptr, size_t size, int access_type, |
| 602 | enum kcsan_value_change value_change, | 602 | enum kcsan_value_change value_change, |
| 603 | enum kcsan_report_type type, int watchpoint_idx) | 603 | enum kcsan_report_type type, int watchpoint_idx) |
| 604 | { | 604 | { |
| 605 | unsigned long flags = 0; | 605 | unsigned long flags = 0; |
| 606 | const struct access_info ai = { | 606 | const struct access_info ai = { |
| @@ -645,3 +645,23 @@ void kcsan_report(const volatile void *ptr, size_t size, int access_type, · 38 unmodified lines | |||
| 645 | out: | 645 | out: |
| 646 | kcsan_enable_current(); | 646 | kcsan_enable_current(); |
| 647 | } | 647 | } |
| 648 | |||
| 649 | void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, | ||
| 650 | int watchpoint_idx) | ||
| 651 | { | ||
| 652 | kcsan_report(ptr, size, access_type, KCSAN_VALUE_CHANGE_MAYBE, | ||
| 653 | KCSAN_REPORT_CONSUMED_WATCHPOINT, watchpoint_idx); | ||
| 654 | } | ||
| 655 | |||
| 656 | void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, | ||
| 657 | enum kcsan_value_change value_change, int watchpoint_idx) | ||
| 658 | { | ||
| 659 | kcsan_report(ptr, size, access_type, value_change, | ||
| 660 | KCSAN_REPORT_RACE_SIGNAL, watchpoint_idx); | ||
| 661 | } | ||
| 662 | |||
| 663 | void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type) | ||
| 664 | { | ||
| 665 | kcsan_report(ptr, size, access_type, KCSAN_VALUE_CHANGE_TRUE, | ||
| 666 | KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, 0); | ||
| 667 | } | ||