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[2.34.30.58]) by smtp.gmail.com with ESMTPSA id e1-20020a0ce3c1000000b0065d52e04f78sm3773031qvl.97.2023.10.09.05.03.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 09 Oct 2023 05:03:20 -0700 (PDT) Message-ID: Date: Mon, 9 Oct 2023 14:03:18 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [PATCH] fpga: Fix memory leak for fpga_region_test_class_find() To: Jinjie Ruan References: <20231007094321.3447084-1-ruanjinjie@huawei.com> Content-Language: en-US Cc: Moritz Fischer , Xu Yilun , Tom Rix , Wu Hao , linux-fpga@vger.kernel.org From: Marco Pagani In-Reply-To: <20231007094321.3447084-1-ruanjinjie@huawei.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-fpga@vger.kernel.org On 2023-10-07 11:43, Jinjie Ruan wrote: > When CONFIG_FPGA_KUNIT_TESTS=m and making CONFIG_DEBUG_KMEMLEAK=y > and CONFIG_DEBUG_KMEMLEAK_AUTO_SCAN=y, modprobe fpga-region-test and then > rmmod fpga-region-test, the below memory leak is detected. > > 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 Looks good to me. Thanks. Reviewed-by: Marco Pagani > 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 > --- > 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 5ff688b394f9..7cd2667d52be 100644 > --- a/drivers/fpga/tests/fpga-region-test.c > +++ b/drivers/fpga/tests/fpga-region-test.c > @@ -95,6 +95,8 @@ 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); > } > > /*