On Mon, 23 Oct 2023 17:07:21 +0800 Fengnan Chang <changfeng...@bytedance.com> wrote:
> Dmitry Kozlyuk <dmitry.kozl...@gmail.com> 于2023年10月23日周一 04:22写道： > > > > 2023-09-22 16:12 (UTC+0800), Fengnan Chang: > > > ping > > > > > > Fengnan Chang <changfeng...@bytedance.com> 于2023年9月12日周二 17:05写道： > > > > > > > > Let's look at this path: > > > > malloc_elem_free > > > > ->malloc_elem_join_adjacent_free > > > > ->join_elem(elem, elem->next) > > > > > > > > 0. cur elem's pad > 0 > > > > 1. data area memset in malloc_elem_free first. > > > > 2. next elem is free, try to join cur elem and next. > > > > 3. in join_elem, try to modify inner->size, this address had > > > > memset in step 1, it casue the content of addrees become non-zero. > > > > > > > > If user call rte_zmalloc, and pick this elem, it can't get all > > > > zero'd memory. > > > > malloc_elem_join_adjacent_free() always calls memset() after join_elem(), > > for the next and the previous element respectively. > when try to call join_elem() for the next element in > malloc_elem_join_adjacent_free(), > the memset is try to memset *next* element, but join_elem() is update > *current* element's > content, which shoudn't happen, it's two different element. > > > How to reproduce this bug? > when I test this patch, > https://patches.dpdk.org/project/dpdk/patch/20230831111937.60975-1-changfeng...@bytedance.com/ > I have a case try to alloc 64/128/192 size object and free with 16 threads, > after every > alloc I'll check wheather all content is 0 or not. > It's not easy to reproduce, you can have a try, it's easier to find > this problem in code level. I tried to make a test that would reproduce the problem but it did not. diff --git a/app/test/test_malloc.c b/app/test/test_malloc.c index cd579c503cf5..cfd45d6a28eb 100644 --- a/app/test/test_malloc.c +++ b/app/test/test_malloc.c @@ -28,6 +28,7 @@ #include <rte_string_fns.h> #define N 10000 +#define BINS 100 static int is_mem_on_socket(int32_t socket); @@ -69,13 +70,24 @@ is_aligned(void *p, int align) return 1; } +static bool is_all_zero(uint8_t *mem, size_t sz) +{ + size_t i; + + for (i = 0; i < sz; i++) + if (mem[i] != 0) + return false; + + return true; +} + static int test_align_overlap_per_lcore(__rte_unused void *arg) { const unsigned align1 = 8, align2 = 64, align3 = 2048; - unsigned i,j; + unsigned int i; void *p1 = NULL, *p2 = NULL, *p3 = NULL; int ret = 0; @@ -86,11 +98,12 @@ test_align_overlap_per_lcore(__rte_unused void *arg) ret = -1; break; } - for(j = 0; j < 1000 ; j++) { - if( *(char *)p1 != 0) { - printf("rte_zmalloc didn't zero the allocated memory\n"); - ret = -1; - } + + if (!is_all_zero(p1, 1000)) { + printf("rte_zmalloc didn't zero the allocated memory\n"); + ret = -1; + rte_free(p1); + break; } p2 = rte_malloc("dummy", 1000, align2); if (!p2){ @@ -140,6 +153,66 @@ test_align_overlap_per_lcore(__rte_unused void *arg) return ret; } +/* + * Allocate random size chunks and make sure that they are + * always zero. + */ +static int +test_zmalloc(__rte_unused void *arg) +{ + unsigned int i, n; + void *slots[BINS] = { }; + void *p1; + size_t sz; + + /* Allocate many variable size chunks */ + for (i = 0; i < BINS; i++) { + sz = rte_rand_max(1024) + 1; + p1 = rte_zmalloc("slots", sz, 0); + if (p1 == NULL) { + printf("rte_zmalloc(%zu) returned NULL (i=%u)\n", sz, i); + goto fail; + } + slots[i] = p1; + if (!is_all_zero(p1, sz)) + goto fail; + } + + /* Drop one chunk per iteration */ + for (n = BINS; n > 0; n--) { + /* Swap in a new block into a slot */ + for (i = 0; i < N; i++) { + unsigned int bin = rte_rand_max(n); + + sz = rte_rand_max(1024) + 1; + p1 = rte_zmalloc("swap", sz, 0); + if (!p1){ + printf("rte_zmalloc(%zu) returned NULL (i=%u)\n", sz, i); + goto fail; + } + + if (!is_all_zero(p1, sz)) { + printf("rte_zmalloc didn't zero the allocated memory\n"); + goto fail; + } + + rte_free(slots[bin]); + slots[bin] = p1; + } + + /* Drop last bin */ + rte_free(slots[n]); + slots[n] = NULL; + } + + return 0; +fail: + for (i = 0; i < BINS; i++) + rte_free(slots[i]); + + return -1; +} + static int test_reordered_free_per_lcore(__rte_unused void *arg) { @@ -1020,6 +1091,21 @@ test_malloc(void) } else printf("test_realloc() passed\n"); + /*----------------------------*/ + RTE_LCORE_FOREACH_WORKER(lcore_id) { + rte_eal_remote_launch(test_zmalloc, NULL, lcore_id); + } + + RTE_LCORE_FOREACH_WORKER(lcore_id) { + if (rte_eal_wait_lcore(lcore_id) < 0) + ret = -1; + } + if (ret < 0){ + printf("test_zmalloc() failed\n"); + return ret; + } + else printf("test_zmalloc() passed\n"); + /*----------------------------*/ RTE_LCORE_FOREACH_WORKER(lcore_id) { rte_eal_remote_launch(test_align_overlap_per_lcore, NULL, lcore_id);
