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-rw-r--r--kernel/kcsan/core.c6
-rw-r--r--kernel/kcsan/report.c11
-rw-r--r--kernel/locking/Makefile3
3 files changed, 18 insertions, 2 deletions
diff --git a/kernel/kcsan/core.c b/kernel/kcsan/core.c
index 87bf857c8893..64b30f7716a1 100644
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -336,8 +336,10 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
* CPU-local data accesses), it makes more sense (from a data race
* detection point of view) to simply disable preemptions to ensure
* as many tasks as possible run on other CPUs.
+ *
+ * Use raw versions, to avoid lockdep recursion via IRQ flags tracing.
*/
- local_irq_save(irq_flags);
+ raw_local_irq_save(irq_flags);
watchpoint = insert_watchpoint((unsigned long)ptr, size, is_write);
if (watchpoint == NULL) {
@@ -429,7 +431,7 @@ kcsan_setup_watchpoint(const volatile void *ptr, size_t size, int type)
kcsan_counter_dec(KCSAN_COUNTER_USED_WATCHPOINTS);
out_unlock:
- local_irq_restore(irq_flags);
+ raw_local_irq_restore(irq_flags);
out:
user_access_restore(ua_flags);
}
diff --git a/kernel/kcsan/report.c b/kernel/kcsan/report.c
index b5b4feea49de..33bdf8b229b5 100644
--- a/kernel/kcsan/report.c
+++ b/kernel/kcsan/report.c
@@ -2,6 +2,7 @@
#include <linux/jiffies.h>
#include <linux/kernel.h>
+#include <linux/lockdep.h>
#include <linux/preempt.h>
#include <linux/printk.h>
#include <linux/sched.h>
@@ -410,6 +411,14 @@ void kcsan_report(const volatile void *ptr, size_t size, int access_type,
{
unsigned long flags = 0;
+ /*
+ * With TRACE_IRQFLAGS, lockdep's IRQ trace state becomes corrupted if
+ * we do not turn off lockdep here; this could happen due to recursion
+ * into lockdep via KCSAN if we detect a data race in utilities used by
+ * lockdep.
+ */
+ lockdep_off();
+
kcsan_disable_current();
if (prepare_report(&flags, ptr, size, access_type, cpu_id, type)) {
if (print_report(ptr, size, access_type, value_change, cpu_id, type) && panic_on_warn)
@@ -418,4 +427,6 @@ void kcsan_report(const volatile void *ptr, size_t size, int access_type,
release_report(&flags, type);
}
kcsan_enable_current();
+
+ lockdep_on();
}
diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
index 45452facff3b..6d11cfb9b41f 100644
--- a/kernel/locking/Makefile
+++ b/kernel/locking/Makefile
@@ -5,6 +5,9 @@ KCOV_INSTRUMENT := n
obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+# Avoid recursion lockdep -> KCSAN -> ... -> lockdep.
+KCSAN_SANITIZE_lockdep.o := n
+
ifdef CONFIG_FUNCTION_TRACER
CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
CFLAGS_REMOVE_lockdep_proc.o = $(CC_FLAGS_FTRACE)