mem: fix deadlock on secondary allocation

Previous fix used `rte_malloc_heap_socket_is_external()` to check if the
heap was an external heap. However, that API is thread-safe, and when
we're inside the allocation process, we're already write-locked, so
calling `rte_malloc_heap_socket_is_external()` will result in a
deadlock followed by a timeout.

Fix it by replacing the API call with a check against maximum number of
NUMA nodes, because external heaps always have higher socket ID's.

Fixes: 7ac31e82bc8f ("mem: improve parameter checking on memory hotplug")

Reported-by: Jim Harris <james.r.harris@intel.com>
Signed-off-by: Anatoly Burakov <anatoly.burakov@intel.com>

diff --git a/lib/librte_eal/common/malloc_mp.c b/lib/librte_eal/common/malloc_mp.c
index 0b19d4d..c7101b3 100644 (file)
--- a/lib/librte_eal/common/malloc_mp.c
+++ b/lib/librte_eal/common/malloc_mp.c
@@ -241,8 +241,13 @@ handle_alloc_request(const struct malloc_mp_req *m,
 
        heap = &mcfg->malloc_heaps[ar->malloc_heap_idx];
 
-       /* for allocations, we must only use internal heaps */
-       if (rte_malloc_heap_socket_is_external(heap->socket_id)) {
+       /*
+        * for allocations, we must only use internal heaps, but since the
+        * rte_malloc_heap_socket_is_external() is thread-safe and we're already
+        * read-locked, we'll have to take advantage of the fact that internal
+        * socket ID's are always lower than RTE_MAX_NUMA_NODES.
+        */
+       if (heap->socket_id >= RTE_MAX_NUMA_NODES) {
                RTE_LOG(ERR, EAL, "Attempting to allocate from external heap\n");
                return -1;
        }