The following kernel memory leak was noticed after running tools/testing/selftests/firmware/fw_run_tests.sh:
[root@pc-mtodorov firmware]# cat /sys/kernel/debug/kmemleak . . . unreferenced object 0xffff955389bc3400 (size 1024): comm "test_firmware-0", pid 5451, jiffies 4294944822 (age 65.652s) hex dump (first 32 bytes): 47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0 [<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240 [<ffffffff962704de>] kmalloc_trace+0x2e/0xc0 [<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180 [<ffffffff95fd813b>] kthread+0x10b/0x140 [<ffffffff95e033e9>] ret_from_fork+0x29/0x50 unreferenced object 0xffff9553c334b400 (size 1024): comm "test_firmware-1", pid 5452, jiffies 4294944822 (age 65.652s) hex dump (first 32 bytes): 47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0 [<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240 [<ffffffff962704de>] kmalloc_trace+0x2e/0xc0 [<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180 [<ffffffff95fd813b>] kthread+0x10b/0x140 [<ffffffff95e033e9>] ret_from_fork+0x29/0x50 unreferenced object 0xffff9553c334f000 (size 1024): comm "test_firmware-2", pid 5453, jiffies 4294944822 (age 65.652s) hex dump (first 32 bytes): 47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0 [<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240 [<ffffffff962704de>] kmalloc_trace+0x2e/0xc0 [<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180 [<ffffffff95fd813b>] kthread+0x10b/0x140 [<ffffffff95e033e9>] ret_from_fork+0x29/0x50 unreferenced object 0xffff9553c3348400 (size 1024): comm "test_firmware-3", pid 5454, jiffies 4294944822 (age 65.652s) hex dump (first 32 bytes): 47 48 34 35 36 37 0a 00 00 00 00 00 00 00 00 00 GH4567.......... 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff962f5dec>] slab_post_alloc_hook+0x8c/0x3c0 [<ffffffff962fcca4>] __kmem_cache_alloc_node+0x184/0x240 [<ffffffff962704de>] kmalloc_trace+0x2e/0xc0 [<ffffffff9665b42d>] test_fw_run_batch_request+0x9d/0x180 [<ffffffff95fd813b>] kthread+0x10b/0x140 [<ffffffff95e033e9>] ret_from_fork+0x29/0x50 [root@pc-mtodorov firmware]#
Note that the size 1024 corresponds to the size of the test firmware buffer. The actual number of the buffers leaked is around 70-110, depending on the test run.
The cause of the leak is the following:
request_partial_firmware_into_buf() and request_firmware_into_buf() provided firmware buffer isn't released on release_firmware(), we have allocated it and we are responsible for deallocating it manually. This is introduced in a number of context where previously only release_firmware() was called, which was insufficient.
Reported-by: Mirsad Goran Todorovac mirsad.todorovac@alu.unizg.hr Fixes: 7feebfa487b92 ("test_firmware: add support for request_firmware_into_buf") Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Cc: Dan Carpenter error27@gmail.com Cc: Takashi Iwai tiwai@suse.de Cc: Luis Chamberlain mcgrof@kernel.org Cc: Russ Weight russell.h.weight@intel.com Cc: Tianfei zhang tianfei.zhang@intel.com Cc: Christophe JAILLET christophe.jaillet@wanadoo.fr Cc: Zhengchao Shao shaozhengchao@huawei.com Cc: Colin Ian King colin.i.king@gmail.com Cc: linux-kernel@vger.kernel.org Cc: Kees Cook keescook@chromium.org Cc: Scott Branden sbranden@broadcom.com Cc: Luis R. Rodriguez mcgrof@kernel.org Cc: linux-kselftest@vger.kernel.org Cc: stable@vger.kernel.org # v5.4 Signed-off-by: Mirsad Goran Todorovac mirsad.todorovac@alu.unizg.hr --- lib/test_firmware.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/lib/test_firmware.c b/lib/test_firmware.c index 91b232ed3161..1d7d480b8eeb 100644 --- a/lib/test_firmware.c +++ b/lib/test_firmware.c @@ -45,6 +45,7 @@ struct test_batched_req { bool sent; const struct firmware *fw; const char *name; + const char *fw_buf; struct completion completion; struct task_struct *task; struct device *dev; @@ -175,8 +176,14 @@ static void __test_release_all_firmware(void)
for (i = 0; i < test_fw_config->num_requests; i++) { req = &test_fw_config->reqs[i]; - if (req->fw) + if (req->fw) { + if (req->fw_buf) { + kfree_const(req->fw_buf); + req->fw_buf = NULL; + } release_firmware(req->fw); + req->fw = NULL; + } }
vfree(test_fw_config->reqs); @@ -670,6 +677,8 @@ static ssize_t trigger_request_store(struct device *dev,
mutex_lock(&test_fw_mutex); release_firmware(test_firmware); + if (test_fw_config->reqs) + __test_release_all_firmware(); test_firmware = NULL; rc = request_firmware(&test_firmware, name, dev); if (rc) { @@ -770,6 +779,8 @@ static ssize_t trigger_async_request_store(struct device *dev, mutex_lock(&test_fw_mutex); release_firmware(test_firmware); test_firmware = NULL; + if (test_fw_config->reqs) + __test_release_all_firmware(); rc = request_firmware_nowait(THIS_MODULE, 1, name, dev, GFP_KERNEL, NULL, trigger_async_request_cb); if (rc) { @@ -812,6 +823,8 @@ static ssize_t trigger_custom_fallback_store(struct device *dev,
mutex_lock(&test_fw_mutex); release_firmware(test_firmware); + if (test_fw_config->reqs) + __test_release_all_firmware(); test_firmware = NULL; rc = request_firmware_nowait(THIS_MODULE, FW_ACTION_NOUEVENT, name, dev, GFP_KERNEL, NULL, @@ -874,6 +887,8 @@ static int test_fw_run_batch_request(void *data) test_fw_config->buf_size); if (!req->fw) kfree(test_buf); + else + req->fw_buf = test_buf; } else { req->rc = test_fw_config->req_firmware(&req->fw, req->name, @@ -934,6 +949,7 @@ static ssize_t trigger_batched_requests_store(struct device *dev, req->fw = NULL; req->idx = i; req->name = test_fw_config->name; + req->fw_buf = NULL; req->dev = dev; init_completion(&req->completion); req->task = kthread_run(test_fw_run_batch_request, req, @@ -1038,6 +1054,7 @@ ssize_t trigger_batched_requests_async_store(struct device *dev, for (i = 0; i < test_fw_config->num_requests; i++) { req = &test_fw_config->reqs[i]; req->name = test_fw_config->name; + req->fw_buf = NULL; req->fw = NULL; req->idx = i; init_completion(&req->completion);