The following commit has been merged into the locking/urgent branch of tip: Commit-ID: 609f809746458522a7a96132acf0ca7ee67c424c Gitweb: https://git.kernel.org/tip/609f809746458522a7a96132acf0ca7ee67c424c Author: Mark Rutland <mark.rutland@xxxxxxx> AuthorDate: Wed, 14 Apr 2021 13:28:23 +02:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Tue, 18 May 2021 10:58:15 -07:00 kcsan: Remove kcsan_report_type Now that the reporting code has been refactored, it's clear by construction that print_report() can only be passed KCSAN_REPORT_RACE_SIGNAL or KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, and these can also be distinguished by the presence of `other_info`. Let's simplify things and remove the report type enum, and instead let's check `other_info` to distinguish these cases. This allows us to remove code for cases which are impossible and generally makes the code simpler. There should be no functional change as a result of this patch. Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx> [ elver@xxxxxxxxxx: add updated comments to kcsan_report_*() functions ] Signed-off-by: Marco Elver <elver@xxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- kernel/kcsan/kcsan.h | 33 +++++++++++++-------------------- kernel/kcsan/report.c | 29 +++++++---------------------- 2 files changed, 20 insertions(+), 42 deletions(-) diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h index 2ee43fd..572f119 100644 --- a/kernel/kcsan/kcsan.h +++ b/kernel/kcsan/kcsan.h @@ -116,32 +116,25 @@ enum kcsan_value_change { KCSAN_VALUE_CHANGE_TRUE, }; -enum kcsan_report_type { - /* - * The thread that set up the watchpoint and briefly stalled was - * signalled that another thread triggered the watchpoint. - */ - KCSAN_REPORT_RACE_SIGNAL, - - /* - * A thread found and consumed a matching watchpoint. - */ - KCSAN_REPORT_CONSUMED_WATCHPOINT, - - /* - * No other thread was observed to race with the access, but the data - * value before and after the stall differs. - */ - KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, -}; - /* - * Notify the report code that a race occurred. + * The calling thread hit and consumed a watchpoint: set the access information + * to be consumed by the reporting thread. No report is printed yet. */ void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type, int watchpoint_idx); + +/* + * The calling thread observed that the watchpoint it set up was hit and + * consumed: print the full report based on information set by the racing + * thread. + */ void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type, enum kcsan_value_change value_change, int watchpoint_idx); + +/* + * No other thread was observed to race with the access, but the data value + * before and after the stall differs. Reports a race of "unknown origin". + */ void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type); #endif /* _KERNEL_KCSAN_KCSAN_H */ diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c index ba924f1..50cee23 100644 --- a/kernel/kcsan/report.c +++ b/kernel/kcsan/report.c @@ -326,7 +326,6 @@ static void print_verbose_info(struct task_struct *task) } static void print_report(enum kcsan_value_change value_change, - enum kcsan_report_type type, const struct access_info *ai, const struct other_info *other_info) { @@ -343,7 +342,7 @@ static void print_report(enum kcsan_value_change value_change, if (skip_report(KCSAN_VALUE_CHANGE_TRUE, stack_entries[skipnr])) return; - if (type == KCSAN_REPORT_RACE_SIGNAL) { + if (other_info) { other_skipnr = get_stack_skipnr(other_info->stack_entries, other_info->num_stack_entries); other_frame = other_info->stack_entries[other_skipnr]; @@ -358,8 +357,7 @@ static void print_report(enum kcsan_value_change value_change, /* Print report header. */ pr_err("==================================================================\n"); - switch (type) { - case KCSAN_REPORT_RACE_SIGNAL: { + if (other_info) { int cmp; /* @@ -371,22 +369,15 @@ static void print_report(enum kcsan_value_change value_change, get_bug_type(ai->access_type | other_info->ai.access_type), (void *)(cmp < 0 ? other_frame : this_frame), (void *)(cmp < 0 ? this_frame : other_frame)); - } break; - - case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + } else { pr_err("BUG: KCSAN: %s in %pS\n", get_bug_type(ai->access_type), (void *)this_frame); - break; - - default: - BUG(); } pr_err("\n"); /* Print information about the racing accesses. */ - switch (type) { - case KCSAN_REPORT_RACE_SIGNAL: + if (other_info) { pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", get_access_type(other_info->ai.access_type), other_info->ai.ptr, other_info->ai.size, get_thread_desc(other_info->ai.task_pid), @@ -404,16 +395,10 @@ static void print_report(enum kcsan_value_change value_change, pr_err("%s to 0x%px of %zu bytes by %s on cpu %i:\n", get_access_type(ai->access_type), ai->ptr, ai->size, get_thread_desc(ai->task_pid), ai->cpu_id); - break; - - case KCSAN_REPORT_RACE_UNKNOWN_ORIGIN: + } else { pr_err("race at unknown origin, with %s to 0x%px of %zu bytes by %s on cpu %i:\n", get_access_type(ai->access_type), ai->ptr, ai->size, get_thread_desc(ai->task_pid), ai->cpu_id); - break; - - default: - BUG(); } /* Print stack trace of this thread. */ stack_trace_print(stack_entries + skipnr, num_stack_entries - skipnr, @@ -623,7 +608,7 @@ void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access * be done once we know the full stack trace in print_report(). */ if (value_change != KCSAN_VALUE_CHANGE_FALSE) - print_report(value_change, KCSAN_REPORT_RACE_SIGNAL, &ai, other_info); + print_report(value_change, &ai, other_info); release_report(&flags, other_info); out: @@ -640,7 +625,7 @@ void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int acce lockdep_off(); /* See kcsan_report_known_origin(). */ raw_spin_lock_irqsave(&report_lock, flags); - print_report(KCSAN_VALUE_CHANGE_TRUE, KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, &ai, NULL); + print_report(KCSAN_VALUE_CHANGE_TRUE, &ai, NULL); raw_spin_unlock_irqrestore(&report_lock, flags); lockdep_on();
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