blob: 7d94cdb9defe467e5d739b014d529f763fbb6601 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
|
From: Thomas Gleixner <tglx@linutronix.de>
Date: Fri, 8 Sep 2023 18:22:53 +0200
Subject: [PATCH 6/7] locking/rtmutex: Add a lockdep assert to catch potential
nested blocking
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.6/older/patches-6.6.7-rt18.tar.xz
There used to be a BUG_ON(current->pi_blocked_on) in the lock acquisition
functions, but that vanished in one of the rtmutex overhauls.
Bring it back in form of a lockdep assert to catch code paths which take
rtmutex based locks with current::pi_blocked_on != NULL.
Reported-by: Crystal Wood <swood@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20230908162254.999499-7-bigeasy@linutronix.de
---
kernel/locking/rtmutex.c | 2 ++
kernel/locking/rwbase_rt.c | 2 ++
kernel/locking/spinlock_rt.c | 2 ++
3 files changed, 6 insertions(+)
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1784,6 +1784,8 @@ static int __sched rt_mutex_slowlock(str
static __always_inline int __rt_mutex_lock(struct rt_mutex_base *lock,
unsigned int state)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (likely(rt_mutex_try_acquire(lock)))
return 0;
--- a/kernel/locking/rwbase_rt.c
+++ b/kernel/locking/rwbase_rt.c
@@ -133,6 +133,8 @@ static int __sched __rwbase_read_lock(st
static __always_inline int rwbase_read_lock(struct rwbase_rt *rwb,
unsigned int state)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (rwbase_read_trylock(rwb))
return 0;
--- a/kernel/locking/spinlock_rt.c
+++ b/kernel/locking/spinlock_rt.c
@@ -37,6 +37,8 @@
static __always_inline void rtlock_lock(struct rt_mutex_base *rtm)
{
+ lockdep_assert(!current->pi_blocked_on);
+
if (unlikely(!rt_mutex_cmpxchg_acquire(rtm, NULL, current)))
rtlock_slowlock(rtm);
}
|
