From 28926daf731f72d0537767fdbab2a3e06e31190a Mon Sep 17 00:00:00 2001 From: Jinjie Ruan Date: Mon, 23 Oct 2023 11:28:57 +0800 Subject: [PATCH] fpga: Fix memory leak for fpga_region_test_class_find() fpga_region_class_find() in fpga_region_test_class_find() will call get_device() if the data is matched, which will increment refcount for dev->kobj, so it should call put_device() to decrement refcount for dev->kobj to free the region, because fpga_region_unregister() will call fpga_region_dev_release() only when the refcount for dev->kobj is zero but fpga_region_test_init() call device_register() in fpga_region_register_full(), which also increment refcount. So call put_device() after calling fpga_region_class_find() in fpga_region_test_class_find(). After applying this patch, the following memory leak is never detected. unreferenced object 0xffff88810c8ef000 (size 1024): comm "kunit_try_catch", pid 1875, jiffies 4294715298 (age 836.836s) hex dump (first 32 bytes): b8 d1 fb 05 81 88 ff ff 08 f0 8e 0c 81 88 ff ff ................ 08 f0 8e 0c 81 88 ff ff 00 00 00 00 00 00 00 00 ................ backtrace: [] kmalloc_trace+0x27/0xa0 [] fpga_region_register_full+0x51/0x430 [fpga_region] [] 0xffffffffa0228e47 [] kunit_try_run_case+0xdd/0x250 [] kunit_generic_run_threadfn_adapter+0x4a/0x90 [] kthread+0x2b5/0x380 [] ret_from_fork+0x2d/0x70 [] ret_from_fork_asm+0x11/0x20 unreferenced object 0xffff888105fbd1b8 (size 8): comm "kunit_try_catch", pid 1875, jiffies 4294715298 (age 836.836s) hex dump (first 8 bytes): 72 65 67 69 6f 6e 30 00 region0. backtrace: [] __kmalloc_node_track_caller+0x53/0x150 [] kvasprintf+0xb0/0x130 [] kobject_set_name_vargs+0x41/0x110 [] dev_set_name+0xab/0xe0 [] fpga_region_register_full+0x312/0x430 [fpga_region] [] 0xffffffffa0228e47 [] kunit_try_run_case+0xdd/0x250 [] kunit_generic_run_threadfn_adapter+0x4a/0x90 [] kthread+0x2b5/0x380 [] ret_from_fork+0x2d/0x70 [] ret_from_fork_asm+0x11/0x20 unreferenced object 0xffff88810b3b8a00 (size 256): comm "kunit_try_catch", pid 1875, jiffies 4294715298 (age 836.836s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 08 8a 3b 0b 81 88 ff ff ..........;..... 08 8a 3b 0b 81 88 ff ff e0 ac 04 83 ff ff ff ff ..;............. backtrace: [] kmalloc_trace+0x27/0xa0 [] device_add+0xa2a/0x15e0 [] fpga_region_register_full+0x321/0x430 [fpga_region] [] 0xffffffffa0228e47 [] kunit_try_run_case+0xdd/0x250 [] kunit_generic_run_threadfn_adapter+0x4a/0x90 [] kthread+0x2b5/0x380 [] ret_from_fork+0x2d/0x70 [] ret_from_fork_asm+0x11/0x20 Fixes: 64a5f972c93d ("fpga: add an initial KUnit suite for the FPGA Region") Signed-off-by: Jinjie Ruan Reviewed-by: Marco Pagani Acked-by: Xu Yilun Link: https://lore.kernel.org/r/20231007094321.3447084-1-ruanjinjie@huawei.com [yilun.xu@intel.com: slightly changes the commit message] Signed-off-by: Xu Yilun Link: https://lore.kernel.org/r/20231023032857.902699-3-yilun.xu@linux.intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/fpga/tests/fpga-region-test.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/fpga/tests/fpga-region-test.c b/drivers/fpga/tests/fpga-region-test.c index 9f9d50e..baab07e 100644 --- a/drivers/fpga/tests/fpga-region-test.c +++ b/drivers/fpga/tests/fpga-region-test.c @@ -93,6 +93,8 @@ static void fpga_region_test_class_find(struct kunit *test) region = fpga_region_class_find(NULL, &ctx->region_pdev->dev, fake_region_match); KUNIT_EXPECT_PTR_EQ(test, region, ctx->region); + + put_device(®ion->dev); } /* -- 2.7.4