trace, lockdep: manual preempt count adding for local_bh_disable

[mirror_ubuntu-hirsute-kernel.git] / kernel / softirq.c

diff --git a/kernel/softirq.c b/kernel/softirq.c
index bdbe9de9cd8d7091771201f232747bf30a83e467..6edfc2c11d99af1c845689adf0e9fbf1043e723d 100644 (file)
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -21,6 +21,7 @@
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/rcupdate.h>
+#include <linux/ftrace.h>
 #include <linux/smp.h>
 #include <linux/tick.h>
 
@@ -79,13 +80,23 @@ static void __local_bh_disable(unsigned long ip)
        WARN_ON_ONCE(in_irq());
 
        raw_local_irq_save(flags);
-       add_preempt_count(SOFTIRQ_OFFSET);
+       /*
+        * The preempt tracer hooks into add_preempt_count and will break
+        * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
+        * is set and before current->softirq_enabled is cleared.
+        * We must manually increment preempt_count here and manually
+        * call the trace_preempt_off later.
+        */
+       preempt_count() += SOFTIRQ_OFFSET;
        /*
         * Were softirqs turned off above:
         */
        if (softirq_count() == SOFTIRQ_OFFSET)
                trace_softirqs_off(ip);
        raw_local_irq_restore(flags);
+
+       if (preempt_count() == SOFTIRQ_OFFSET)
+               trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
 }
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip)