selftests/xsk: Fix munmap for hugepage allocated umem

Fix the unmapping of hugepage allocated umems so that they are
properly unmapped. The new test referred to in the fixes label,
introduced a test that allocated a umem that is not a multiple of a 2M
hugepage size. This is fine for mmap() that rounds the size up the
nearest multiple of 2M. But munmap() requires the size to be a
multiple of the hugepage size in order for it to unmap the region. The
current behaviour of not properly unmapping the umem, was discovered
when further additions of tests that require hugepages (unaligned mode
tests only) started failing as the system was running out of
hugepages.

Fixes: c0801598e543 ("selftests: xsk: Add test UNALIGNED_INV_DESC_4K1_FRAME_SIZE")
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230418143617.27762-1-magnus.karlsson@gmail.com

diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
index 5a9691e942de0705c2c21a1c20aa2779aae7ceb5..a59d04118842a749fd14aa21b9e2fbe660121883 100644 (file)
--- a/tools/testing/selftests/bpf/xskxceiver.c
+++ b/tools/testing/selftests/bpf/xskxceiver.c
@@ -77,6 +77,7 @@
 #include <linux/if_link.h>
 #include <linux/if_ether.h>
 #include <linux/ip.h>
+#include <linux/mman.h>
 #include <linux/udp.h>
 #include <arpa/inet.h>
 #include <net/if.h>
@@ -1286,16 +1287,19 @@ static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
        u64 umem_sz = ifobject->umem->num_frames * ifobject->umem->frame_size;
        int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
        LIBBPF_OPTS(bpf_xdp_query_opts, opts);
+       off_t mmap_offset = 0;
        void *bufs;
        int ret;
 
-       if (ifobject->umem->unaligned_mode)
+       if (ifobject->umem->unaligned_mode) {
                mmap_flags |= MAP_HUGETLB;
+               mmap_offset = MAP_HUGE_2MB;
+       }
 
        if (ifobject->shared_umem)
                umem_sz *= 2;
 
-       bufs = mmap(NULL, umem_sz, PROT_READ | PROT_WRITE, mmap_flags, -1, 0);
+       bufs = mmap(NULL, umem_sz, PROT_READ | PROT_WRITE, mmap_flags, -1, mmap_offset);
        if (bufs == MAP_FAILED)
                exit_with_error(errno);
 
@@ -1379,6 +1383,11 @@ static void *worker_testapp_validate_rx(void *arg)
        pthread_exit(NULL);
 }
 
+static u64 ceil_u64(u64 a, u64 b)
+{
+       return (a + b - 1) / b;
+}
+
 static void testapp_clean_xsk_umem(struct ifobject *ifobj)
 {
        u64 umem_sz = ifobj->umem->num_frames * ifobj->umem->frame_size;
@@ -1386,6 +1395,7 @@ static void testapp_clean_xsk_umem(struct ifobject *ifobj)
        if (ifobj->shared_umem)
                umem_sz *= 2;
 
+       umem_sz = ceil_u64(umem_sz, HUGEPAGE_SIZE) * HUGEPAGE_SIZE;
        xsk_umem__delete(ifobj->umem->umem);
        munmap(ifobj->umem->buffer, umem_sz);
 }
@@ -1619,14 +1629,15 @@ static void testapp_stats_fill_empty(struct test_spec *test)
 /* Simple test */
 static bool hugepages_present(struct ifobject *ifobject)
 {
-       const size_t mmap_sz = 2 * ifobject->umem->num_frames * ifobject->umem->frame_size;
+       size_t mmap_sz = 2 * ifobject->umem->num_frames * ifobject->umem->frame_size;
        void *bufs;
 
        bufs = mmap(NULL, mmap_sz, PROT_READ | PROT_WRITE,
-                   MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, 0);
+                   MAP_PRIVATE | MAP_ANONYMOUS | MAP_HUGETLB, -1, MAP_HUGE_2MB);
        if (bufs == MAP_FAILED)
                return false;
 
+       mmap_sz = ceil_u64(mmap_sz, HUGEPAGE_SIZE) * HUGEPAGE_SIZE;
        munmap(bufs, mmap_sz);
        return true;
 }

diff --git a/tools/testing/selftests/bpf/xskxceiver.h b/tools/testing/selftests/bpf/xskxceiver.h
index 919327807a4eee12de4448e4333aff08e0d48f7b..c535aeab2ca353c998b11fa51bc5b86f9e369382 100644 (file)
--- a/tools/testing/selftests/bpf/xskxceiver.h
+++ b/tools/testing/selftests/bpf/xskxceiver.h
@@ -56,6 +56,7 @@
 #define RX_FULL_RXQSIZE 32
 #define UMEM_HEADROOM_TEST_SIZE 128
 #define XSK_UMEM__INVALID_FRAME_SIZE (XSK_UMEM__DEFAULT_FRAME_SIZE + 1)
+#define HUGEPAGE_SIZE (2 * 1024 * 1024)
 
 #define print_verbose(x...) do { if (opt_verbose) ksft_print_msg(x); } while (0)