[PATCH 15/37] softirq: Pass softirq vector number to lockdep on vector execution

Frederic Weisbecker
2019-02-28T17:13:49Z

Pass the softirq vector number to lockdep on callback execution so that
we know which one is involved while holding a lock. We will then be able
to pick up the proper LOCK_USED_IN_*_SOFTIRQ index to perform the
finegrained verifications.

Reviewed-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Pavan Kondeti <pkondeti@codeaurora.org>
Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com>
Cc: David S . Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
---
include/linux/irqflags.h | 12 ++++++------
kernel/softirq.c | 8 ++++----
lib/locking-selftest.c | 4 ++--
3 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/include/linux/irqflags.h b/include/linux/irqflags.h
index 21619c92c377..623030a74866 100644
--- a/include/linux/irqflags.h
+++ b/include/linux/irqflags.h
@@ -43,13 +43,13 @@ do { \
do { \
current->hardirq_context--; \
} while (0)
-# define lockdep_softirq_enter() \
+# define lockdep_softirq_enter(__VEC) \
do { \
- current->softirq_context++; \
+ current->softirq_context |= BIT(__VEC); \
} while (0)
-# define lockdep_softirq_exit() \
+# define lockdep_softirq_exit(__VEC) \
do { \
- current->softirq_context--; \
+ current->softirq_context &= ~BIT(__VEC);\
} while (0)
#else
# define trace_hardirqs_on() do { } while (0)
@@ -60,8 +60,8 @@ do { \
# define trace_softirqs_enabled(p) 0
# define trace_hardirq_enter() do { } while (0)
# define trace_hardirq_exit() do { } while (0)
-# define lockdep_softirq_enter() do { } while (0)
-# define lockdep_softirq_exit() do { } while (0)
+# define lockdep_softirq_enter(vec) do { } while (0)
+# define lockdep_softirq_exit(vec) do { } while (0)
#endif

#if defined(CONFIG_IRQSOFF_TRACER) || \
diff --git a/kernel/softirq.c b/kernel/softirq.c
index d28813306b2c..2dcaef813acb 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -229,18 +229,15 @@ static inline bool lockdep_softirq_start(void)
trace_hardirq_exit();
}

- lockdep_softirq_enter();
-
return in_hardirq;
}

static inline void lockdep_softirq_end(bool in_hardirq)
{
- lockdep_softirq_exit();
-
if (in_hardirq)
trace_hardirq_enter();
}
+
#else
static inline bool lockdep_softirq_start(void) { return false; }
static inline void lockdep_softirq_end(bool in_hardirq) { }
@@ -288,9 +285,12 @@ asmlinkage __visible void __softirq_entry __do_softirq(void)

kstat_incr_softirqs_this_cpu(vec_nr);

+ lockdep_softirq_enter(vec_nr);
trace_softirq_entry(vec_nr);
h->action(h);
trace_softirq_exit(vec_nr);
+ lockdep_softirq_exit(vec_nr);
+
if (unlikely(prev_count != preempt_count())) {
pr_err("huh, entered softirq %u %s %p with preempt_count %08x, exited with %08x?\n",
vec_nr, softirq_to_name[vec_nr], h->action,
diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c
index 1e1bbf171eca..2bd782d7f2e5 100644
--- a/lib/locking-selftest.c
+++ b/lib/locking-selftest.c
@@ -197,11 +197,11 @@ static void init_shared_classes(void)
#define SOFTIRQ_ENTER() \
local_bh_disable(); \
local_irq_disable(); \
- lockdep_softirq_enter(); \
+ lockdep_softirq_enter(0); \
WARN_ON(!in_softirq());

#define SOFTIRQ_EXIT() \
- lockdep_softirq_exit(); \
+ lockdep_softirq_exit(0); \
local_irq_enable(); \
local_bh_enable();

--
2.21.0