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kmemleak: Handle percpu memory allocation

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This patch adds kmemleak callbacks from the percpu allocator, reducing a
number of false positives caused by kmemleak not scanning such memory
blocks. The percpu chunks are never reported as leaks because of current
kmemleak limitations with the __percpu pointer not pointing directly to
the actual chunks.

Reported-by: Huajun Li <huajun.li.lee@gmail.com>
Acked-by: Christoph Lameter <cl@gentwo.org>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Catalin Marinas
2011-09-26 17:12:53 +01:00
parent 74341703ed
commit f528f0b8e5
4 changed files with 94 additions and 1 deletions
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72
mm/kmemleak.c
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@@ -230,8 +230,10 @@ static int kmemleak_skip_disable;
/* kmemleak operation type for early logging */
enum {
KMEMLEAK_ALLOC,
KMEMLEAK_ALLOC_PERCPU,
KMEMLEAK_FREE,
KMEMLEAK_FREE_PART,
KMEMLEAK_FREE_PERCPU,
KMEMLEAK_NOT_LEAK,
KMEMLEAK_IGNORE,
KMEMLEAK_SCAN_AREA,
@@ -852,6 +854,20 @@ out:
rcu_read_unlock();
}
/*
* Log an early allocated block and populate the stack trace.
*/
static void early_alloc_percpu(struct early_log *log)
{
unsigned int cpu;
const void __percpu *ptr = log->ptr;
for_each_possible_cpu(cpu) {
log->ptr = per_cpu_ptr(ptr, cpu);
early_alloc(log);
}
}
/**
* kmemleak_alloc - register a newly allocated object
* @ptr: pointer to beginning of the object
@@ -878,6 +894,34 @@ void __ref kmemleak_alloc(const void *ptr, size_t size, int min_count,
}
EXPORT_SYMBOL_GPL(kmemleak_alloc);
/**
* kmemleak_alloc_percpu - register a newly allocated __percpu object
* @ptr: __percpu pointer to beginning of the object
* @size: size of the object
*
* This function is called from the kernel percpu allocator when a new object
* (memory block) is allocated (alloc_percpu). It assumes GFP_KERNEL
* allocation.
*/
void __ref kmemleak_alloc_percpu(const void __percpu *ptr, size_t size)
{
unsigned int cpu;
pr_debug("%s(0x%p, %zu)\n", __func__, ptr, size);
/*
* Percpu allocations are only scanned and not reported as leaks
* (min_count is set to 0).
*/
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
create_object((unsigned long)per_cpu_ptr(ptr, cpu),
size, 0, GFP_KERNEL);
else if (atomic_read(&kmemleak_early_log))
log_early(KMEMLEAK_ALLOC_PERCPU, ptr, size, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_alloc_percpu);
/**
* kmemleak_free - unregister a previously registered object
* @ptr: pointer to beginning of the object
@@ -916,6 +960,28 @@ void __ref kmemleak_free_part(const void *ptr, size_t size)
}
EXPORT_SYMBOL_GPL(kmemleak_free_part);
/**
* kmemleak_free_percpu - unregister a previously registered __percpu object
* @ptr: __percpu pointer to beginning of the object
*
* This function is called from the kernel percpu allocator when an object
* (memory block) is freed (free_percpu).
*/
void __ref kmemleak_free_percpu(const void __percpu *ptr)
{
unsigned int cpu;
pr_debug("%s(0x%p)\n", __func__, ptr);
if (atomic_read(&kmemleak_enabled) && ptr && !IS_ERR(ptr))
for_each_possible_cpu(cpu)
delete_object_full((unsigned long)per_cpu_ptr(ptr,
cpu));
else if (atomic_read(&kmemleak_early_log))
log_early(KMEMLEAK_FREE_PERCPU, ptr, 0, 0);
}
EXPORT_SYMBOL_GPL(kmemleak_free_percpu);
/**
* kmemleak_not_leak - mark an allocated object as false positive
* @ptr: pointer to beginning of the object
@@ -1727,12 +1793,18 @@ void __init kmemleak_init(void)
case KMEMLEAK_ALLOC:
early_alloc(log);
break;
case KMEMLEAK_ALLOC_PERCPU:
early_alloc_percpu(log);
break;
case KMEMLEAK_FREE:
kmemleak_free(log->ptr);
break;
case KMEMLEAK_FREE_PART:
kmemleak_free_part(log->ptr, log->size);
break;
case KMEMLEAK_FREE_PERCPU:
kmemleak_free_percpu(log->ptr);
break;
case KMEMLEAK_NOT_LEAK:
kmemleak_not_leak(log->ptr);
break;