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
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
|
From: He Zhe <zhe.he@windriver.com>
Date: Wed, 19 Dec 2018 16:30:57 +0100
Subject: [PATCH 024/354] kmemleak: Turn kmemleak_lock to raw spinlock on RT
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Origin: https://git.kernel.org/cgit/linux/kernel/git/rt/linux-stable-rt.git/commit?id=aaca0331f02dfc36b0ca67ea9c0da7300a9daa4f
kmemleak_lock, as a rwlock on RT, can possibly be held in atomic context and
causes the follow BUG.
BUG: scheduling while atomic: migration/15/132/0x00000002
Preemption disabled at:
[<ffffffff8c927c11>] cpu_stopper_thread+0x71/0x100
CPU: 15 PID: 132 Comm: migration/15 Not tainted 4.19.0-rt1-preempt-rt #1
Call Trace:
schedule+0x3d/0xe0
__rt_spin_lock+0x26/0x30
__write_rt_lock+0x23/0x1a0
rt_write_lock+0x2a/0x30
find_and_remove_object+0x1e/0x80
delete_object_full+0x10/0x20
kmemleak_free+0x32/0x50
kfree+0x104/0x1f0
intel_pmu_cpu_dying+0x67/0x70
x86_pmu_dying_cpu+0x1a/0x30
cpuhp_invoke_callback+0x92/0x700
take_cpu_down+0x70/0xa0
multi_cpu_stop+0x62/0xc0
cpu_stopper_thread+0x79/0x100
smpboot_thread_fn+0x20f/0x2d0
kthread+0x121/0x140
And on v4.18 stable tree the following call trace, caused by grabbing
kmemleak_lock again, is also observed.
kernel BUG at kernel/locking/rtmutex.c:1048!
CPU: 5 PID: 689 Comm: mkfs.ext4 Not tainted 4.18.16-rt9-preempt-rt #1
Call Trace:
rt_write_lock+0x2a/0x30
create_object+0x17d/0x2b0
kmemleak_alloc+0x34/0x50
kmem_cache_alloc+0x146/0x220
mempool_alloc_slab+0x15/0x20
mempool_alloc+0x65/0x170
sg_pool_alloc+0x21/0x60
sg_alloc_table_chained+0x8b/0xb0
…
blk_flush_plug_list+0x204/0x230
schedule+0x87/0xe0
rt_write_lock+0x2a/0x30
create_object+0x17d/0x2b0
kmemleak_alloc+0x34/0x50
__kmalloc_node+0x1cd/0x340
alloc_request_size+0x30/0x70
mempool_alloc+0x65/0x170
get_request+0x4e3/0x8d0
blk_queue_bio+0x153/0x470
generic_make_request+0x1dc/0x3f0
submit_bio+0x49/0x140
…
kmemleak is an error detecting feature. We would not expect as good performance
as without it. As there is no raw rwlock defining helpers, we turn kmemleak_lock
to a raw spinlock.
Signed-off-by: He Zhe <zhe.he@windriver.com>
Cc: catalin.marinas@arm.com
Cc: bigeasy@linutronix.de
Cc: tglx@linutronix.de
Cc: rostedt@goodmis.org
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lkml.kernel.org/r/1542877459-144382-1-git-send-email-zhe.he@windriver.com
Link: https://lkml.kernel.org/r/20181218150744.GB20197@arrakis.emea.arm.com
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
mm/kmemleak.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index f54734abf946..86caf2025c35 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -26,7 +26,7 @@
*
* The following locks and mutexes are used by kmemleak:
*
- * - kmemleak_lock (rwlock): protects the object_list modifications and
+ * - kmemleak_lock (raw spinlock): protects the object_list modifications and
* accesses to the object_tree_root. The object_list is the main list
* holding the metadata (struct kmemleak_object) for the allocated memory
* blocks. The object_tree_root is a red black tree used to look-up
@@ -197,7 +197,7 @@ static LIST_HEAD(gray_list);
/* search tree for object boundaries */
static struct rb_root object_tree_root = RB_ROOT;
/* rw_lock protecting the access to object_list and object_tree_root */
-static DEFINE_RWLOCK(kmemleak_lock);
+static DEFINE_RAW_SPINLOCK(kmemleak_lock);
/* allocation caches for kmemleak internal data */
static struct kmem_cache *object_cache;
@@ -491,9 +491,9 @@ static struct kmemleak_object *find_and_get_object(unsigned long ptr, int alias)
struct kmemleak_object *object;
rcu_read_lock();
- read_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = lookup_object(ptr, alias);
- read_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
/* check whether the object is still available */
if (object && !get_object(object))
@@ -513,13 +513,13 @@ static struct kmemleak_object *find_and_remove_object(unsigned long ptr, int ali
unsigned long flags;
struct kmemleak_object *object;
- write_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = lookup_object(ptr, alias);
if (object) {
rb_erase(&object->rb_node, &object_tree_root);
list_del_rcu(&object->object_list);
}
- write_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
@@ -593,7 +593,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
/* kernel backtrace */
object->trace_len = __save_stack_trace(object->trace);
- write_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
min_addr = min(min_addr, ptr);
max_addr = max(max_addr, ptr + size);
@@ -624,7 +624,7 @@ static struct kmemleak_object *create_object(unsigned long ptr, size_t size,
list_add_tail_rcu(&object->object_list, &object_list);
out:
- write_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
@@ -1310,7 +1310,7 @@ static void scan_block(void *_start, void *_end,
unsigned long *end = _end - (BYTES_PER_POINTER - 1);
unsigned long flags;
- read_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
for (ptr = start; ptr < end; ptr++) {
struct kmemleak_object *object;
unsigned long pointer;
@@ -1367,7 +1367,7 @@ static void scan_block(void *_start, void *_end,
spin_unlock(&object->lock);
}
}
- read_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/*
|
