From f528f0b8e53d73b18be71e96693cfab9322f33c7 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 26 Sep 2011 17:12:53 +0100 Subject: kmemleak: Handle percpu memory allocation 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 Acked-by: Christoph Lameter Acked-by: Tejun Heo Signed-off-by: Catalin Marinas --- mm/kmemleak.c | 72 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ mm/percpu.c | 12 +++++++++- 2 files changed, 83 insertions(+), 1 deletion(-) (limited to 'mm') diff --git a/mm/kmemleak.c b/mm/kmemleak.c index b4f4e6021c1..15c50302ff9 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -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; diff --git a/mm/percpu.c b/mm/percpu.c index 3bb810a7200..86c5bdbdc37 100644 --- a/mm/percpu.c +++ b/mm/percpu.c @@ -67,6 +67,7 @@ #include #include #include +#include #include #include @@ -710,6 +711,7 @@ static void __percpu *pcpu_alloc(size_t size, size_t align, bool reserved) const char *err; int slot, off, new_alloc; unsigned long flags; + void __percpu *ptr; if (unlikely(!size || size > PCPU_MIN_UNIT_SIZE || align > PAGE_SIZE)) { WARN(true, "illegal size (%zu) or align (%zu) for " @@ -802,7 +804,9 @@ area_found: mutex_unlock(&pcpu_alloc_mutex); /* return address relative to base address */ - return __addr_to_pcpu_ptr(chunk->base_addr + off); + ptr = __addr_to_pcpu_ptr(chunk->base_addr + off); + kmemleak_alloc_percpu(ptr, size); + return ptr; fail_unlock: spin_unlock_irqrestore(&pcpu_lock, flags); @@ -916,6 +920,8 @@ void free_percpu(void __percpu *ptr) if (!ptr) return; + kmemleak_free_percpu(ptr); + addr = __pcpu_ptr_to_addr(ptr); spin_lock_irqsave(&pcpu_lock, flags); @@ -1637,6 +1643,8 @@ int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size, rc = -ENOMEM; goto out_free_areas; } + /* kmemleak tracks the percpu allocations separately */ + kmemleak_free(ptr); areas[group] = ptr; base = min(ptr, base); @@ -1751,6 +1759,8 @@ int __init pcpu_page_first_chunk(size_t reserved_size, "for cpu%u\n", psize_str, cpu); goto enomem; } + /* kmemleak tracks the percpu allocations separately */ + kmemleak_free(ptr); pages[j++] = virt_to_page(ptr); } -- cgit v1.2.3