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 03/10] kcsan: Distinguish kcsan_report() calls
Date: Tue, 11 May 2021 16:23:54 -0700 [thread overview]
Message-ID: <20210511232401.2896217-3-paulmck@kernel.org> (raw)
In-Reply-To: <20210511231149.GA2895263@paulmck-ThinkPad-P17-Gen-1>
From: Mark Rutland <mark.rutland@arm.com>
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.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
[ elver@google.com: try to make kcsan_report_*() names more descriptive ]
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
kernel/kcsan/core.c | 12 ++++--------
kernel/kcsan/kcsan.h | 10 ++++++----
kernel/kcsan/report.c | 26 +++++++++++++++++++++++---
3 files changed, 33 insertions(+), 15 deletions(-)
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index d360183002d6..6fe1513e1e6a 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -380,9 +380,7 @@ static noinline void kcsan_found_watchpoint(const volatile void *ptr,
if (consumed) {
kcsan_save_irqtrace(current);
- kcsan_report(ptr, size, type, KCSAN_VALUE_CHANGE_MAYBE,
- KCSAN_REPORT_CONSUMED_WATCHPOINT,
- watchpoint - watchpoints);
+ kcsan_report_set_info(ptr, size, type, watchpoint - watchpoints);
kcsan_restore_irqtrace(current);
} else {
/*
@@ -558,8 +556,8 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
if (is_assert && value_change == KCSAN_VALUE_CHANGE_TRUE)
atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]);
- kcsan_report(ptr, size, type, value_change, KCSAN_REPORT_RACE_SIGNAL,
- watchpoint - watchpoints);
+ kcsan_report_known_origin(ptr, size, type, value_change,
+ watchpoint - watchpoints);
} else if (value_change == KCSAN_VALUE_CHANGE_TRUE) {
/* Inferring a race, since the value should not have changed. */
@@ -568,9 +566,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
atomic_long_inc(&kcsan_counters[KCSAN_COUNTER_ASSERT_FAILURES]);
if (IS_ENABLED(CONFIG_KCSAN_REPORT_RACE_UNKNOWN_ORIGIN) || is_assert)
- kcsan_report(ptr, size, type, KCSAN_VALUE_CHANGE_TRUE,
- KCSAN_REPORT_RACE_UNKNOWN_ORIGIN,
- watchpoint - watchpoints);
+ kcsan_report_unknown_origin(ptr, size, type);
}
/*
diff --git a/kernel/kcsan/kcsan.h b/kernel/kcsan/kcsan.h
index 9881099d4179..2ee43fd5d6a4 100644
--- a/kernel/kcsan/kcsan.h
+++ b/kernel/kcsan/kcsan.h
@@ -136,10 +136,12 @@ enum kcsan_report_type {
};
/*
- * Print a race report from thread that encountered the race.
+ * Notify the report code that a race occurred.
*/
-extern void kcsan_report(const volatile void *ptr, size_t size, int access_type,
- enum kcsan_value_change value_change,
- enum kcsan_report_type type, int watchpoint_idx);
+void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
+ int watchpoint_idx);
+void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
+ enum kcsan_value_change value_change, int watchpoint_idx);
+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 13dce3c664d6..5232bf218ea7 100644
--- a/kernel/kcsan/report.c
+++ b/kernel/kcsan/report.c
@@ -598,9 +598,9 @@ static noinline bool prepare_report(unsigned long *flags,
}
}
-void kcsan_report(const volatile void *ptr, size_t size, int access_type,
- enum kcsan_value_change value_change,
- enum kcsan_report_type type, int watchpoint_idx)
+static void kcsan_report(const volatile void *ptr, size_t size, int access_type,
+ enum kcsan_value_change value_change,
+ enum kcsan_report_type type, int watchpoint_idx)
{
unsigned long flags = 0;
const struct access_info ai = {
@@ -645,3 +645,23 @@ void kcsan_report(const volatile void *ptr, size_t size, int access_type,
out:
kcsan_enable_current();
}
+
+void kcsan_report_set_info(const volatile void *ptr, size_t size, int access_type,
+ int watchpoint_idx)
+{
+ kcsan_report(ptr, size, access_type, KCSAN_VALUE_CHANGE_MAYBE,
+ KCSAN_REPORT_CONSUMED_WATCHPOINT, watchpoint_idx);
+}
+
+void kcsan_report_known_origin(const volatile void *ptr, size_t size, int access_type,
+ enum kcsan_value_change value_change, int watchpoint_idx)
+{
+ kcsan_report(ptr, size, access_type, value_change,
+ KCSAN_REPORT_RACE_SIGNAL, watchpoint_idx);
+}
+
+void kcsan_report_unknown_origin(const volatile void *ptr, size_t size, int access_type)
+{
+ kcsan_report(ptr, size, access_type, KCSAN_VALUE_CHANGE_TRUE,
+ KCSAN_REPORT_RACE_UNKNOWN_ORIGIN, 0);
+}
--
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 ` Paul E. McKenney [this message]
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 ` [PATCH tip/core/rcu 08/10] kcsan: Remove kcsan_report_type Paul E. McKenney
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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