[Linaro-mm-sig] Re: [RFC v3 8/8] selftests: Add binder cgroup gpu memory transfer test

On Wed, Mar 9, 2022 at 1:31 PM Shuah Khan skhan@linuxfoundation.org wrote:

On 3/9/22 9:52 AM, T.J. Mercier wrote:

...

This test verifies that the cgroup GPU memory charge is transferred correctly when a dmabuf is passed between processes in two different cgroups and the sender specifies BINDER_BUFFER_FLAG_SENDER_NO_NEED in the binder transaction data containing the dmabuf file descriptor.

Signed-off-by: T.J. Mercier tjmercier@google.com

.../selftests/drivers/android/binder/Makefile | 8 + .../drivers/android/binder/binder_util.c | 254 +++++++++ .../drivers/android/binder/binder_util.h | 32 ++ .../selftests/drivers/android/binder/config | 4 + .../binder/test_dmabuf_cgroup_transfer.c | 480 ++++++++++++++++++ 5 files changed, 778 insertions(+) create mode 100644 tools/testing/selftests/drivers/android/binder/Makefile create mode 100644 tools/testing/selftests/drivers/android/binder/binder_util.c create mode 100644 tools/testing/selftests/drivers/android/binder/binder_util.h create mode 100644 tools/testing/selftests/drivers/android/binder/config create mode 100644 tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c

diff --git a/tools/testing/selftests/drivers/android/binder/Makefile b/tools/testing/selftests/drivers/android/binder/Makefile new file mode 100644 index 000000000000..726439d10675 --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0 +CFLAGS += -Wall

Does this test inteded to be built on all architectures? Is arch check necessary here?

I think this test should be runnable on any architecture, so long as the correct kernel configs (for binder and cgroups) are enabled. I have tested it on arm64 and x86-64.

Also does this test require root previleges - I see mount and unmount operations in the test. If so add root check and skip if non-root user runs the test.

Yes, currently it does. Thanks, I will add this check at the location you have pointed out in the TEST function.

...

+TEST_GEN_PROGS = test_dmabuf_cgroup_transfer

+include ../../../lib.mk

+$(OUTPUT)/test_dmabuf_cgroup_transfer: ../../../cgroup/cgroup_util.c binder_util.c diff --git a/tools/testing/selftests/drivers/android/binder/binder_util.c b/tools/testing/selftests/drivers/android/binder/binder_util.c new file mode 100644 index 000000000000..c9dcf5b9d42b --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/binder_util.c @@ -0,0 +1,254 @@ +// SPDX-License-Identifier: GPL-2.0

+#include "binder_util.h"

+#include <errno.h> +#include <fcntl.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/mount.h>

+#include <linux/limits.h> +#include <linux/android/binder.h> +#include <linux/android/binderfs.h>

+static const size_t BINDER_MMAP_SIZE = 64 * 1024;

+static void binderfs_unmount(const char *mountpoint) +{

• if (umount2(mountpoint, MNT_DETACH))
  

•         fprintf(stderr, "Failed to unmount binderfs at %s: %s\n",
  

•                 mountpoint, strerror(errno));
  

• else
  

•         fprintf(stderr, "Binderfs unmounted: %s\n", mountpoint);
  

• if (rmdir(mountpoint))
  

•         fprintf(stderr, "Failed to remove binderfs mount %s: %s\n",
  

•                 mountpoint, strerror(errno));
  

• else
  

•         fprintf(stderr, "Binderfs mountpoint destroyed: %s\n", mountpoint);
  

Does umount require root previleges? Same commment as above about non-root user running test.

...

+}

+struct binderfs_ctx create_binderfs(const char *name) +{

• int fd, ret, saved_errno;
  

• struct binderfs_device device = { 0 };
  

• struct binderfs_ctx ctx = { 0 };
  

• /*
  

•  * P_tmpdir is set to "/tmp/" on Android platforms where Binder is most
  

•  * commonly used, but this path does not actually exist on Android. We
  

•  * will first try using "/data/local/tmp" and fallback to P_tmpdir if
  

•  * that fails for non-Android platforms.
  

•  */
  

• static const char tmpdir[] = "/data/local/tmp";
  

• static const size_t MAX_TMPDIR_SIZE =
  

•         sizeof(tmpdir) > sizeof(P_tmpdir) ?
  

•         sizeof(tmpdir) : sizeof(P_tmpdir);
  

• static const char template[] = "/binderfs_XXXXXX";
  

• char *mkdtemp_result;
  

• char binderfs_mntpt[MAX_TMPDIR_SIZE + sizeof(template)];
  

• char device_path[MAX_TMPDIR_SIZE + sizeof(template) + BINDERFS_MAX_NAME];
  

• snprintf(binderfs_mntpt, sizeof(binderfs_mntpt), "%s%s", tmpdir, template);
  

• mkdtemp_result = mkdtemp(binderfs_mntpt);
  

• if (mkdtemp_result == NULL) {
  

•         fprintf(stderr, "Failed to create binderfs mountpoint at %s: %s.\n",
  

•                 binderfs_mntpt, strerror(errno));
  

•         fprintf(stderr, "Trying fallback mountpoint...\n");
  

•         snprintf(binderfs_mntpt, sizeof(binderfs_mntpt), "%s%s", P_tmpdir, template);
  

•         if (mkdtemp(binderfs_mntpt) == NULL) {
  

•                 fprintf(stderr, "Failed to create binderfs mountpoint at %s: %s\n",
  

•                 binderfs_mntpt, strerror(errno));
  

•                 return ctx;
  

•         }
  

• }
  

• fprintf(stderr, "Binderfs mountpoint created at %s\n", binderfs_mntpt);
  

Does mount require root previleges? Same commment as above about non-root user running test.

...

• if (mount(NULL, binderfs_mntpt, "binder", 0, 0)) {
  

•         perror("Could not mount binderfs");
  

•         rmdir(binderfs_mntpt);
  

•         return ctx;
  

• }
  

• fprintf(stderr, "Binderfs mounted at %s\n", binderfs_mntpt);
  

• strncpy(device.name, name, sizeof(device.name));
  

• snprintf(device_path, sizeof(device_path), "%s/binder-control", binderfs_mntpt);
  

• fd = open(device_path, O_RDONLY | O_CLOEXEC);
  

• if (!fd) {
  

•         perror("Failed to open binder-control device");
  

•         binderfs_unmount(binderfs_mntpt);
  

•         return ctx;
  

• }
  

• ret = ioctl(fd, BINDER_CTL_ADD, &device);
  

• saved_errno = errno;
  

• close(fd);
  

• errno = saved_errno;
  

• if (ret) {
  

•         perror("Failed to allocate new binder device");
  

•         binderfs_unmount(binderfs_mntpt);
  

•         return ctx;
  

• }
  

• fprintf(stderr, "Allocated new binder device with major %d, minor %d, and name %s at %s\n",
  

•         device.major, device.minor, device.name, binderfs_mntpt);
  

• ctx.name = strdup(name);
  

• ctx.mountpoint = strdup(binderfs_mntpt);
  

• return ctx;
  

+}

+void destroy_binderfs(struct binderfs_ctx *ctx) +{

• char path[PATH_MAX];
  

• snprintf(path, sizeof(path), "%s/%s", ctx->mountpoint, ctx->name);
  

• if (unlink(path))
  

•         fprintf(stderr, "Failed to unlink binder device %s: %s\n", path, strerror(errno));
  

• else
  

•         fprintf(stderr, "Destroyed binder %s at %s\n", ctx->name, ctx->mountpoint);
  

• binderfs_unmount(ctx->mountpoint);
  

• free(ctx->name);
  

• free(ctx->mountpoint);
  

+}

+struct binder_ctx open_binder(struct binderfs_ctx *bfs_ctx) +{

• struct binder_ctx ctx = {.fd = -1, .memory = NULL};
  

• char path[PATH_MAX];
  

• snprintf(path, sizeof(path), "%s/%s", bfs_ctx->mountpoint, bfs_ctx->name);
  

• ctx.fd = open(path, O_RDWR | O_NONBLOCK | O_CLOEXEC);
  

• if (ctx.fd < 0) {
  

•         fprintf(stderr, "Error opening binder device %s: %s\n", path, strerror(errno));
  

Does this require root previleges?

...

•         return ctx;
  

• }
  

• ctx.memory = mmap(NULL, BINDER_MMAP_SIZE, PROT_READ, MAP_SHARED, ctx.fd, 0);
  

• if (ctx.memory == NULL) {
  

•         perror("Error mapping binder memory");
  

•         close(ctx.fd);
  

•         ctx.fd = -1;
  

• }
  

• return ctx;
  

+}

+void close_binder(struct binder_ctx *ctx) +{

• if (munmap(ctx->memory, BINDER_MMAP_SIZE))
  

•         perror("Failed to unmap binder memory");
  

• ctx->memory = NULL;
  

• if (close(ctx->fd))
  

•         perror("Failed to close binder");
  

• ctx->fd = -1;
  

+}

+int become_binder_context_manager(int binder_fd) +{

• return ioctl(binder_fd, BINDER_SET_CONTEXT_MGR, 0);
  

+}

+int do_binder_write_read(int binder_fd, void *writebuf, binder_size_t writesize,

•                  void *readbuf, binder_size_t readsize)
  

+{

• int err;
  

• struct binder_write_read bwr = {
  

•         .write_buffer = (binder_uintptr_t)writebuf,
  

•         .write_size = writesize,
  

•         .read_buffer = (binder_uintptr_t)readbuf,
  

•         .read_size = readsize
  

• };
  

• do {
  

•         if (ioctl(binder_fd, BINDER_WRITE_READ, &bwr) >= 0)
  

•                 err = 0;
  

•         else
  

•                 err = -errno;
  

• } while (err == -EINTR);
  

• if (err < 0) {
  

•         perror("BINDER_WRITE_READ");
  

•         return -1;
  

• }
  

• if (bwr.write_consumed < writesize) {
  

•         fprintf(stderr, "Binder did not consume full write buffer %llu %llu\n",
  

•                 bwr.write_consumed, writesize);
  

•         return -1;
  

• }
  

• return bwr.read_consumed;
  

+}

+static const char *reply_string(int cmd) +{

• switch (cmd) {
  

• case BR_ERROR:
  

•         return("BR_ERROR");
  

• case BR_OK:
  

•         return("BR_OK");
  

• case BR_TRANSACTION_SEC_CTX:
  

•         return("BR_TRANSACTION_SEC_CTX");
  

• case BR_TRANSACTION:
  

•         return("BR_TRANSACTION");
  

• case BR_REPLY:
  

•         return("BR_REPLY");
  

• case BR_ACQUIRE_RESULT:
  

•         return("BR_ACQUIRE_RESULT");
  

• case BR_DEAD_REPLY:
  

•         return("BR_DEAD_REPLY");
  

• case BR_TRANSACTION_COMPLETE:
  

•         return("BR_TRANSACTION_COMPLETE");
  

• case BR_INCREFS:
  

•         return("BR_INCREFS");
  

• case BR_ACQUIRE:
  

•         return("BR_ACQUIRE");
  

• case BR_RELEASE:
  

•         return("BR_RELEASE");
  

• case BR_DECREFS:
  

•         return("BR_DECREFS");
  

• case BR_ATTEMPT_ACQUIRE:
  

•         return("BR_ATTEMPT_ACQUIRE");
  

• case BR_NOOP:
  

•         return("BR_NOOP");
  

• case BR_SPAWN_LOOPER:
  

•         return("BR_SPAWN_LOOPER");
  

• case BR_FINISHED:
  

•         return("BR_FINISHED");
  

• case BR_DEAD_BINDER:
  

•         return("BR_DEAD_BINDER");
  

• case BR_CLEAR_DEATH_NOTIFICATION_DONE:
  

•         return("BR_CLEAR_DEATH_NOTIFICATION_DONE");
  

• case BR_FAILED_REPLY:
  

•         return("BR_FAILED_REPLY");
  

• case BR_FROZEN_REPLY:
  

•         return("BR_FROZEN_REPLY");
  

• case BR_ONEWAY_SPAM_SUSPECT:
  

•         return("BR_ONEWAY_SPAM_SUSPECT");
  

• default:
  

•         return("Unknown");
  

• };
  

+}

+int expect_binder_reply(int32_t actual, int32_t expected) +{

• if (actual != expected) {
  

•         fprintf(stderr, "Expected %s but received %s\n",
  

•                 reply_string(expected), reply_string(actual));
  

•         return -1;
  

• }
  

• return 0;
  

+}

diff --git a/tools/testing/selftests/drivers/android/binder/binder_util.h b/tools/testing/selftests/drivers/android/binder/binder_util.h new file mode 100644 index 000000000000..807f5abe987e --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/binder_util.h @@ -0,0 +1,32 @@ +/* SPDX-License-Identifier: GPL-2.0 */

+#ifndef SELFTEST_BINDER_UTIL_H +#define SELFTEST_BINDER_UTIL_H

+#include <stdint.h>

+#include <linux/android/binder.h>

+struct binderfs_ctx {

• char *name;
  

• char *mountpoint;
  

+};

+struct binder_ctx {

• int fd;
  

• void *memory;
  

+};

+struct binderfs_ctx create_binderfs(const char *name); +void destroy_binderfs(struct binderfs_ctx *ctx);

+struct binder_ctx open_binder(struct binderfs_ctx *bfs_ctx); +void close_binder(struct binder_ctx *ctx);

+int become_binder_context_manager(int binder_fd);

+int do_binder_write_read(int binder_fd, void *writebuf, binder_size_t writesize,

•                  void *readbuf, binder_size_t readsize);
  

+int expect_binder_reply(int32_t actual, int32_t expected); +#endif diff --git a/tools/testing/selftests/drivers/android/binder/config b/tools/testing/selftests/drivers/android/binder/config new file mode 100644 index 000000000000..fcc5f8f693b3 --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/config @@ -0,0 +1,4 @@ +CONFIG_CGROUP_GPU=y +CONFIG_ANDROID=y +CONFIG_ANDROID_BINDERFS=y +CONFIG_ANDROID_BINDER_IPC=y diff --git a/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c b/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c new file mode 100644 index 000000000000..9b952ab401cc --- /dev/null +++ b/tools/testing/selftests/drivers/android/binder/test_dmabuf_cgroup_transfer.c @@ -0,0 +1,480 @@ +// SPDX-License-Identifier: GPL-2.0

+/*

• • This test verifies that the cgroup GPU memory charge is transferred correctly
• • when a dmabuf is passed between processes in two different cgroups and the
• • sender specifies BINDER_BUFFER_FLAG_SENDER_NO_NEED in the binder transaction
• • data containing the dmabuf file descriptor.
• • The gpu_cgroup_dmabuf_transfer test function becomes the binder context
• • manager, then forks a child who initiates a transaction with the context
• • manager by specifying a target of 0. The context manager reply contains a
• • dmabuf file descriptor which was allocated by the gpu_cgroup_dmabuf_transfer
• • test function, but should be charged to the child cgroup after the binder
• • transaction.
• */

+#include <errno.h> +#include <fcntl.h> +#include <stddef.h> +#include <stdint.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/epoll.h> +#include <sys/ioctl.h> +#include <sys/types.h> +#include <sys/wait.h>

+#include "binder_util.h" +#include "../../../cgroup/cgroup_util.h" +#include "../../../kselftest.h" +#include "../../../kselftest_harness.h"

+#include <linux/limits.h> +#include <linux/dma-heap.h> +#include <linux/android/binder.h>

+#define UNUSED(x) ((void)(x))

+static const unsigned int BINDER_CODE = 8675309; /* Any number will work here */

+struct cgroup_ctx {

• char *root;
  

• char *source;
  

• char *dest;
  

+};

+void destroy_cgroups(struct __test_metadata *_metadata, struct cgroup_ctx *ctx) +{

• if (ctx->source != NULL) {
  

•         TH_LOG("Destroying cgroup: %s", ctx->source);
  

•         rmdir(ctx->source);
  

•         free(ctx->source);
  

• }
  

• if (ctx->dest != NULL) {
  

•         TH_LOG("Destroying cgroup: %s", ctx->dest);
  

•         rmdir(ctx->dest);
  

•         free(ctx->dest);
  

• }
  

• free(ctx->root);
  

• ctx->root = ctx->source = ctx->dest = NULL;
  

+}

+struct cgroup_ctx create_cgroups(struct __test_metadata *_metadata) +{

• struct cgroup_ctx ctx = {0};
  

• char root[PATH_MAX], *tmp;
  

• static const char template[] = "/gpucg_XXXXXX";
  

• if (cg_find_unified_root(root, sizeof(root))) {
  

•         TH_LOG("Could not find cgroups root");
  

•         return ctx;
  

• }
  

• if (cg_read_strstr(root, "cgroup.controllers", "gpu")) {
  

•         TH_LOG("Could not find GPU controller");
  

•         return ctx;
  

• }
  

• if (cg_write(root, "cgroup.subtree_control", "+gpu")) {
  

•         TH_LOG("Could not enable GPU controller");
  

•         return ctx;
  

• }
  

• ctx.root = strdup(root);
  

• snprintf(root, sizeof(root), "%s/%s", ctx.root, template);
  

• tmp = mkdtemp(root);
  

• if (tmp == NULL) {
  

•         TH_LOG("%s - Could not create source cgroup", strerror(errno));
  

•         destroy_cgroups(_metadata, &ctx);
  

•         return ctx;
  

• }
  

• ctx.source = strdup(tmp);
  

• snprintf(root, sizeof(root), "%s/%s", ctx.root, template);
  

• tmp = mkdtemp(root);
  

• if (tmp == NULL) {
  

•         TH_LOG("%s - Could not create destination cgroup", strerror(errno));
  

•         destroy_cgroups(_metadata, &ctx);
  

•         return ctx;
  

• }
  

• ctx.dest = strdup(tmp);
  

• TH_LOG("Created cgroups: %s %s", ctx.source, ctx.dest);
  

• return ctx;
  

+}

+int dmabuf_heap_alloc(int fd, size_t len, int *dmabuf_fd) +{

• struct dma_heap_allocation_data data = {
  

•         .len = len,
  

•         .fd = 0,
  

•         .fd_flags = O_RDONLY | O_CLOEXEC,
  

•         .heap_flags = 0,
  

• };
  

• int ret;
  

• if (!dmabuf_fd)
  

•         return -EINVAL;
  

• ret = ioctl(fd, DMA_HEAP_IOCTL_ALLOC, &data);
  

• if (ret < 0)
  

•         return ret;
  

• *dmabuf_fd = (int)data.fd;
  

• return ret;
  

+}

+/* The system heap is known to export dmabufs with support for cgroup tracking */ +int alloc_dmabuf_from_system_heap(struct __test_metadata *_metadata, size_t bytes) +{

• int heap_fd = -1, dmabuf_fd = -1;
  

• static const char * const heap_path = "/dev/dma_heap/system";
  

• heap_fd = open(heap_path, O_RDONLY);
  

• if (heap_fd < 0) {
  

•         TH_LOG("%s - open %s failed!\n", strerror(errno), heap_path);
  

•         return -1;
  

• }
  

Same question about root preveliges?

...

• if (dmabuf_heap_alloc(heap_fd, bytes, &dmabuf_fd))
  

•         TH_LOG("dmabuf allocation failed! - %s", strerror(errno));
  

• close(heap_fd);
  

• return dmabuf_fd;
  

+}

+int binder_request_dmabuf(int binder_fd) +{

• int ret;
  

• /*
  

•  * We just send an empty binder_buffer_object to initiate a transaction
  

•  * with the context manager, who should respond with a single dmabuf
  

•  * inside a binder_fd_array_object.
  

•  */
  

• struct binder_buffer_object bbo = {
  

•         .hdr.type = BINDER_TYPE_PTR,
  

•         .flags = 0,
  

•         .buffer = 0,
  

•         .length = 0,
  

•         .parent = 0, /* No parent */
  

•         .parent_offset = 0 /* No parent */
  

• };
  

• binder_size_t offsets[] = {0};
  

• struct {
  

•         int32_t cmd;
  

•         struct binder_transaction_data btd;
  

• } __attribute__((packed)) bc = {
  

•         .cmd = BC_TRANSACTION,
  

•         .btd = {
  

•                 .target = { 0 },
  

•                 .cookie = 0,
  

•                 .code = BINDER_CODE,
  

•                 .flags = TF_ACCEPT_FDS, /* We expect a FDA in the reply */
  

•                 .data_size = sizeof(bbo),
  

•                 .offsets_size = sizeof(offsets),
  

•                 .data.ptr = {
  

•                         (binder_uintptr_t)&bbo,
  

•                         (binder_uintptr_t)offsets
  

•                 }
  

•         },
  

• };
  

• struct {
  

•         int32_t reply_noop;
  

• } __attribute__((packed)) br;
  

• ret = do_binder_write_read(binder_fd, &bc, sizeof(bc), &br, sizeof(br));
  

• if (ret >= sizeof(br) && expect_binder_reply(br.reply_noop, BR_NOOP)) {
  

•         return -1;
  

• } else if (ret < sizeof(br)) {
  

•         fprintf(stderr, "Not enough bytes in binder reply %d\n", ret);
  

•         return -1;
  

• }
  

• return 0;
  

+}

+int send_dmabuf_reply(int binder_fd, struct binder_transaction_data *tr, int dmabuf_fd) +{

• int ret;
  

• /*
  

•  * The trailing 0 is to achieve the necessary alignment for the binder
  

•  * buffer_size.
  

•  */
  

• int fdarray[] = { dmabuf_fd, 0 };
  

• struct binder_buffer_object bbo = {
  

•         .hdr.type = BINDER_TYPE_PTR,
  

•         .flags = BINDER_BUFFER_FLAG_SENDER_NO_NEED,
  

•         .buffer = (binder_uintptr_t)fdarray,
  

•         .length = sizeof(fdarray),
  

•         .parent = 0, /* No parent */
  

•         .parent_offset = 0 /* No parent */
  

• };
  

• struct binder_fd_array_object bfdao = {
  

•         .hdr.type = BINDER_TYPE_FDA,
  

•         .num_fds = 1,
  

•         .parent = 0, /* The binder_buffer_object */
  

•         .parent_offset = 0 /* FDs follow immediately */
  

• };
  

• uint64_t sz = sizeof(fdarray);
  

• uint8_t data[sizeof(sz) + sizeof(bbo) + sizeof(bfdao)];
  

• binder_size_t offsets[] = {sizeof(sz), sizeof(sz)+sizeof(bbo)};
  

• memcpy(data,                            &sz, sizeof(sz));
  

• memcpy(data + sizeof(sz),               &bbo, sizeof(bbo));
  

• memcpy(data + sizeof(sz) + sizeof(bbo), &bfdao, sizeof(bfdao));
  

• struct {
  

•         int32_t cmd;
  

•         struct binder_transaction_data_sg btd;
  

• } __attribute__((packed)) bc = {
  

•         .cmd = BC_REPLY_SG,
  

•         .btd.transaction_data = {
  

•                 .target = { tr->target.handle },
  

•                 .cookie = tr->cookie,
  

•                 .code = BINDER_CODE,
  

•                 .flags = 0,
  

•                 .data_size = sizeof(data),
  

•                 .offsets_size = sizeof(offsets),
  

•                 .data.ptr = {
  

•                         (binder_uintptr_t)data,
  

•                         (binder_uintptr_t)offsets
  

•                 }
  

•         },
  

•         .btd.buffers_size = sizeof(fdarray)
  

• };
  

• struct {
  

•         int32_t reply_noop;
  

• } __attribute__((packed)) br;
  

• ret = do_binder_write_read(binder_fd, &bc, sizeof(bc), &br, sizeof(br));
  

• if (ret >= sizeof(br) && expect_binder_reply(br.reply_noop, BR_NOOP)) {
  

•         return -1;
  

• } else if (ret < sizeof(br)) {
  

•         fprintf(stderr, "Not enough bytes in binder reply %d\n", ret);
  

•         return -1;
  

• }
  

• return 0;
  

+}

+struct binder_transaction_data *binder_wait_for_transaction(int binder_fd,

•                                                     uint32_t *readbuf,
  

•                                                     size_t readsize)
  

+{

• static const int MAX_EVENTS = 1, EPOLL_WAIT_TIME_MS = 3 * 1000;
  

• struct binder_reply {
  

•         int32_t reply0;
  

•         int32_t reply1;
  

•         struct binder_transaction_data btd;
  

• } *br;
  

• struct binder_transaction_data *ret = NULL;
  

• struct epoll_event events[MAX_EVENTS];
  

• int epoll_fd, num_events, readcount;
  

• uint32_t bc[] = { BC_ENTER_LOOPER };
  

• do_binder_write_read(binder_fd, &bc, sizeof(bc), NULL, 0);
  

• epoll_fd = epoll_create1(EPOLL_CLOEXEC);
  

• if (epoll_fd == -1) {
  

•         perror("epoll_create");
  

•         return NULL;
  

• }
  

• events[0].events = EPOLLIN;
  

• if (epoll_ctl(epoll_fd, EPOLL_CTL_ADD, binder_fd, &events[0])) {
  

•         perror("epoll_ctl add");
  

•         goto err_close;
  

• }
  

• num_events = epoll_wait(epoll_fd, events, MAX_EVENTS, EPOLL_WAIT_TIME_MS);
  

• if (num_events < 0) {
  

•         perror("epoll_wait");
  

•         goto err_ctl;
  

• } else if (num_events == 0) {
  

•         fprintf(stderr, "No events\n");
  

•         goto err_ctl;
  

• }
  

• readcount = do_binder_write_read(binder_fd, NULL, 0, readbuf, readsize);
  

• fprintf(stderr, "Read %d bytes from binder\n", readcount);
  

• if (readcount < (int)sizeof(struct binder_reply)) {
  

•         fprintf(stderr, "read_consumed not large enough\n");
  

•         goto err_ctl;
  

• }
  

• br = (struct binder_reply *)readbuf;
  

• if (expect_binder_reply(br->reply0, BR_NOOP))
  

•         goto err_ctl;
  

• if (br->reply1 == BR_TRANSACTION) {
  

•         if (br->btd.code == BINDER_CODE)
  

•                 ret = &br->btd;
  

•         else
  

•                 fprintf(stderr, "Received transaction with unexpected code: %u\n",
  

•                         br->btd.code);
  

• } else {
  

•         expect_binder_reply(br->reply1, BR_TRANSACTION_COMPLETE);
  

• }
  

+err_ctl:

• if (epoll_ctl(epoll_fd, EPOLL_CTL_DEL, binder_fd, NULL))
  

•         perror("epoll_ctl del");
  

+err_close:

• close(epoll_fd);
  

• return ret;
  

+}

+static int child_request_dmabuf_transfer(const char *cgroup, void *arg) +{

• UNUSED(cgroup);
  

• int ret = -1;
  

• uint32_t readbuf[32];
  

• struct binderfs_ctx bfs_ctx = *(struct binderfs_ctx *)arg;
  

• struct binder_ctx b_ctx;
  

• fprintf(stderr, "Child PID: %d\n", getpid());
  

• b_ctx = open_binder(&bfs_ctx);
  

• if (b_ctx.fd < 0) {
  

•         fprintf(stderr, "Child unable to open binder\n");
  

•         return -1;
  

• }
  

• if (binder_request_dmabuf(b_ctx.fd))
  

•         goto err;
  

• /* The child must stay alive until the binder reply is received */
  

• if (binder_wait_for_transaction(b_ctx.fd, readbuf, sizeof(readbuf)) == NULL)
  

•         ret = 0;
  

• /*
  

•  * We don't close the received dmabuf here so that the parent can
  

•  * inspect the cgroup gpu memory charges to verify the charge transfer
  

•  * completed successfully.
  

•  */
  

+err:

• close_binder(&b_ctx);
  

• fprintf(stderr, "Child done\n");
  

• return ret;
  

+}

+TEST(gpu_cgroup_dmabuf_transfer) +{

• static const char * const GPUMEM_FILENAME = "gpu.memory.current";
  

• static const size_t ONE_MiB = 1024 * 1024;
  

• int ret, dmabuf_fd;
  

• uint32_t readbuf[32];
  

• long memsize;
  

• pid_t child_pid;
  

• struct binderfs_ctx bfs_ctx;
  

• struct binder_ctx b_ctx;
  

• struct cgroup_ctx cg_ctx;
  

• struct binder_transaction_data *tr;
  

• struct flat_binder_object *fbo;
  

• struct binder_buffer_object *bbo;
  

If root previges is necessary - pls add check here and skip.

...

• bfs_ctx = create_binderfs("testbinder");
  

• if (bfs_ctx.name == NULL)
  

•         ksft_exit_skip("The Android binderfs filesystem is not available\n");
  

• cg_ctx = create_cgroups(_metadata);
  

• if (cg_ctx.root == NULL) {
  

•         destroy_binderfs(&bfs_ctx);
  

•         ksft_exit_skip("cgroup v2 isn't mounted\n");
  

• }
  

• ASSERT_EQ(cg_enter_current(cg_ctx.source), 0) {
  

•         TH_LOG("Could not move parent to cgroup: %s", cg_ctx.source);
  

•         goto err_cg;
  

• }
  

• dmabuf_fd = alloc_dmabuf_from_system_heap(_metadata, ONE_MiB);
  

• ASSERT_GE(dmabuf_fd, 0) {
  

•         goto err_cg;
  

• }
  

• TH_LOG("Allocated dmabuf");
  

• memsize = cg_read_key_long(cg_ctx.source, GPUMEM_FILENAME, "system");
  

• ASSERT_EQ(memsize, ONE_MiB) {
  

•         TH_LOG("GPU memory used after allocation: %ld but it should be %lu",
  

•                memsize, (unsigned long)ONE_MiB);
  

•         goto err_dmabuf;
  

• }
  

• b_ctx = open_binder(&bfs_ctx);
  

• ASSERT_GE(b_ctx.fd, 0) {
  

•         TH_LOG("Parent unable to open binder");
  

•         goto err_dmabuf;
  

• }
  

• TH_LOG("Opened binder at %s/%s", bfs_ctx.mountpoint, bfs_ctx.name);
  

• ASSERT_EQ(become_binder_context_manager(b_ctx.fd), 0) {
  

•         TH_LOG("Cannot become context manager: %s", strerror(errno));
  

•         goto err_binder;
  

• }
  

• child_pid = cg_run_nowait(cg_ctx.dest, child_request_dmabuf_transfer, &bfs_ctx);
  

• ASSERT_GT(child_pid, 0) {
  

•         TH_LOG("Error forking: %s", strerror(errno));
  

•         goto err_binder;
  

• }
  

• tr = binder_wait_for_transaction(b_ctx.fd, readbuf, sizeof(readbuf));
  

• ASSERT_NE(tr, NULL) {
  

•         TH_LOG("Error receiving transaction request from child");
  

•         goto err_child;
  

• }
  

• fbo = (struct flat_binder_object *)tr->data.ptr.buffer;
  

• ASSERT_EQ(fbo->hdr.type, BINDER_TYPE_PTR) {
  

•         TH_LOG("Did not receive a buffer object from child");
  

•         goto err_child;
  

• }
  

• bbo = (struct binder_buffer_object *)fbo;
  

• ASSERT_EQ(bbo->length, 0) {
  

•         TH_LOG("Did not receive an empty buffer object from child");
  

•         goto err_child;
  

• }
  

• TH_LOG("Received transaction from child");
  

• send_dmabuf_reply(b_ctx.fd, tr, dmabuf_fd);
  

• ASSERT_EQ(cg_read_key_long(cg_ctx.dest, GPUMEM_FILENAME, "system"), ONE_MiB) {
  

•         TH_LOG("Destination cgroup does not have system charge!");
  

•         goto err_child;
  

• }
  

• ASSERT_EQ(cg_read_key_long(cg_ctx.source, GPUMEM_FILENAME, "system"), 0) {
  

•         TH_LOG("Source cgroup still has system charge!");
  

•         goto err_child;
  

• }
  

• TH_LOG("Charge transfer succeeded!");
  

+err_child:

• waitpid(child_pid, &ret, 0);
  

• if (WIFEXITED(ret))
  

•         TH_LOG("Child %d terminated with %d", child_pid, WEXITSTATUS(ret));
  

• else
  

•         TH_LOG("Child terminated abnormally");
  

What does this mean? What are the conditions that could cause this? Pls include more info. in the message.

This would be very unusual, but possible if the child is (accidentally?) killed by a user or the low/out of memory killer. It looks like I can add more information with the WIFSIGNALED and WTERMSIG macros, so I will do that.

...

+err_binder:

• close_binder(&b_ctx);
  

+err_dmabuf:

• close(dmabuf_fd);
  

+err_cg:

• destroy_cgroups(_metadata, &cg_ctx);
  

• destroy_binderfs(&bfs_ctx);
  

+}

+TEST_HARNESS_MAIN

thanks, -- Shuah

Thanks for taking a look!