From: "Paul E. McKenney" <paulmck@kernel.org>
To: linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
kernel-team@fb.com, mingo@kernel.org
Cc: elver@google.com, andreyknvl@google.com, glider@google.com,
dvyukov@google.com, cai@lca.pw, boqun.feng@gmail.com,
Mark Rutland <mark.rutland@arm.com>,
"Paul E . McKenney" <paulmck@kernel.org>
Subject: [PATCH tip/core/rcu 08/10] kcsan: Remove kcsan_report_type
Date: Tue, 11 May 2021 16:23:59 -0700 [thread overview]
Message-ID: <20210511232401.2896217-8-paulmck@kernel.org> (raw)
In-Reply-To: <20210511231149.GA2895263@paulmck-ThinkPad-P17-Gen-1>
From: Mark Rutland <mark.rutland@arm.com>
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@arm.com>
[ elver@google.com: add updated comments to kcsan_report_*() functions ]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
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 2ee43fd5d6a4..572f119a19eb 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 ba924f110c95..50cee2357885 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();
--
2.31.1.189.g2e36527f23
next prev parent reply other threads:[~2021-05-11 23:24 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 23:11 [PATCH tip/core/rcu 0/26] Torture-test updates for v5.14 Paul E. McKenney
2021-05-11 23:11 ` [PATCH tip/core/rcu 01/26] torture: Fix remaining erroneous torture.sh instance of $* Paul E. McKenney
2021-05-11 23:11 ` [PATCH tip/core/rcu 02/26] torture: Add "scenarios" option to kvm.sh --dryrun parameter Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 03/26] torture: Make kvm-again.sh use "scenarios" rather than "batches" file Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 04/26] refscale: Allow CPU hotplug to be enabled Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 05/26] rcuscale: " Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 06/26] torture: Add kvm-remote.sh script for distributed rcutorture test runs Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 07/26] refscale: Add acqrel, lock, and lock-irq Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 08/26] rcutorture: Abstract read-lock-held checks Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 09/26] torture: Fix grace-period rate output Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 10/26] torture: Abstract end-of-run summary Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 11/26] torture: Make kvm.sh use abstracted kvm-end-run-stats.sh Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 12/26] torture: Make the build machine control N in "make -jN" Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 13/26] torture: Make kvm-find-errors.sh account for kvm-remote.sh Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 14/26] rcutorture: Judge RCU priority boosting on grace periods, not callbacks Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 15/26] torture: Correctly fetch number of CPUs for non-English languages Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 16/26] torture: Set kvm.sh language to English Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 17/26] rcutorture: Delay-based false positives for RCU priority boosting tests Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 18/26] rcutorture: Consolidate rcu_torture_boost() timing and statistics Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 19/26] rcutorture: Make rcu_torture_boost_failed() check for GP end Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 20/26] rcutorture: Add BUSTED-BOOST to test RCU priority boosting tests Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 21/26] rcutorture: Forgive RCU boost failures when CPUs don't pass through QS Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 22/26] rcutorture: Don't count CPU-stalled time against priority boosting Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 23/26] torture: Make kvm-remote.sh account for network failure in pathname checks Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 24/26] torture: Don't cap remote runs by build-system number of CPUs Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 25/26] rcutorture: Move mem_dump_obj() tests into separate function Paul E. McKenney
2021-05-11 23:12 ` [PATCH tip/core/rcu 26/26] rcu: Don't penalize priority boosting when there is nothing to boost Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 01/10] kcsan: Add pointer to access-marking.txt to data_race() bullet Paul E. McKenney
2021-05-13 10:47 ` Akira Yokosawa
2021-05-13 10:53 ` Marco Elver
2021-05-13 17:50 ` Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 02/10] kcsan: Simplify value change detection Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 03/10] kcsan: Distinguish kcsan_report() calls Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 04/10] kcsan: Refactor passing watchpoint/other_info Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 05/10] kcsan: Fold panic() call into print_report() Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 06/10] kcsan: Refactor access_info initialization Paul E. McKenney
2021-05-11 23:23 ` [PATCH tip/core/rcu 07/10] kcsan: Remove reporting indirection Paul E. McKenney
2021-05-11 23:23 ` Paul E. McKenney [this message]
2021-05-11 23:24 ` [PATCH tip/core/rcu 09/10] kcsan: Report observed value changes Paul E. McKenney
2021-05-11 23:24 ` [PATCH tip/core/rcu 10/10] kcsan: Document "value changed" line Paul E. McKenney
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