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From: He Zhe <zhe.he@windriver.com>
Date: Wed, 19 Dec 2018 16:30:57 +0100
Subject: [PATCH] kmemleak: Turn kmemleak_lock to raw spinlock on RT
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.4/older/patches-5.4.3-rt1.tar.xz
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 | 28 ++++++++++++++--------------
1 file changed, 14 insertions(+), 14 deletions(-)
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -13,7 +13,7 @@
*
* 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
@@ -192,7 +192,7 @@ static LIST_HEAD(mem_pool_free_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;
@@ -426,7 +426,7 @@ static struct kmemleak_object *mem_pool_
}
/* slab allocation failed, try the memory pool */
- write_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
object = list_first_entry_or_null(&mem_pool_free_list,
typeof(*object), object_list);
if (object)
@@ -435,7 +435,7 @@ static struct kmemleak_object *mem_pool_
object = &mem_pool[--mem_pool_free_count];
else
pr_warn_once("Memory pool empty, consider increasing CONFIG_DEBUG_KMEMLEAK_MEM_POOL_SIZE\n");
- write_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
@@ -453,9 +453,9 @@ static void mem_pool_free(struct kmemlea
}
/* add the object to the memory pool free list */
- write_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
list_add(&object->object_list, &mem_pool_free_list);
- write_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/*
@@ -514,9 +514,9 @@ static struct kmemleak_object *find_and_
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))
@@ -546,11 +546,11 @@ static struct kmemleak_object *find_and_
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)
__remove_object(object);
- write_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
return object;
}
@@ -617,7 +617,7 @@ static struct kmemleak_object *create_ob
/* kernel backtrace */
object->trace_len = __save_stack_trace(object->trace);
- write_lock_irqsave(&kmemleak_lock, flags);
+ raw_spin_lock_irqsave(&kmemleak_lock, flags);
untagged_ptr = (unsigned long)kasan_reset_tag((void *)ptr);
min_addr = min(min_addr, untagged_ptr);
@@ -649,7 +649,7 @@ static struct kmemleak_object *create_ob
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;
}
@@ -1233,7 +1233,7 @@ static void scan_block(void *_start, voi
unsigned long flags;
unsigned long untagged_ptr;
- 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;
@@ -1291,7 +1291,7 @@ static void scan_block(void *_start, voi
spin_unlock(&object->lock);
}
}
- read_unlock_irqrestore(&kmemleak_lock, flags);
+ raw_spin_unlock_irqrestore(&kmemleak_lock, flags);
}
/*
|
