malloc: protect stats with lock

When we're gathering statistics, we are traversing the freelist,
which may change under our feet in multithreaded scenario. This
is verified by occasional segfaults when running malloc autotest
on a machine with big amount of cores.

This patch protects malloc heap stats call with a lock. It changes
its definition in the process due to locking invalidating the
const-ness, but this isn't a public API, so that's OK.

Fixes: 2a5c356e177d ("memory: stats for malloc")
Cc: stable@dpdk.org
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

diff --git a/lib/librte_eal/common/malloc_heap.c b/lib/librte_eal/common/malloc_heap.c
index b98b3af..7aafc88 100644 (file)
--- a/lib/librte_eal/common/malloc_heap.c
+++ b/lib/librte_eal/common/malloc_heap.c
@@ -149,12 +149,14 @@ malloc_heap_alloc(struct malloc_heap *heap,
  * Function to retrieve data for heap on given socket
  */
 int
-malloc_heap_get_stats(const struct malloc_heap *heap,
+malloc_heap_get_stats(struct malloc_heap *heap,
                struct rte_malloc_socket_stats *socket_stats)
 {
        size_t idx;
        struct malloc_elem *elem;
 
+       rte_spinlock_lock(&heap->lock);
+
        /* Initialise variables for heap */
        socket_stats->free_count = 0;
        socket_stats->heap_freesz_bytes = 0;
@@ -176,6 +178,8 @@ malloc_heap_get_stats(const struct malloc_heap *heap,
        socket_stats->heap_allocsz_bytes = (socket_stats->heap_totalsz_bytes -
                        socket_stats->heap_freesz_bytes);
        socket_stats->alloc_count = heap->alloc_count;
+
+       rte_spinlock_unlock(&heap->lock);
        return 0;
 }
 

diff --git a/lib/librte_eal/common/malloc_heap.h b/lib/librte_eal/common/malloc_heap.h
index be5e6e6..e0defa7 100644 (file)
--- a/lib/librte_eal/common/malloc_heap.h
+++ b/lib/librte_eal/common/malloc_heap.h
@@ -28,7 +28,7 @@ malloc_heap_alloc(struct malloc_heap *heap,   const char *type, size_t size,
                unsigned flags, size_t align, size_t bound);
 
 int
-malloc_heap_get_stats(const struct malloc_heap *heap,
+malloc_heap_get_stats(struct malloc_heap *heap,
                struct rte_malloc_socket_stats *socket_stats);
 
 int