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 <marpagan@xxxxxxxxxx>
> 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:
> [<ffffffff817ebad7>] kmalloc_trace+0x27/0xa0
> [<ffffffffa02385e1>] fpga_region_register_full+0x51/0x430 [fpga_region]
> [<ffffffffa0228e47>] 0xffffffffa0228e47
> [<ffffffff829c479d>] kunit_try_run_case+0xdd/0x250
> [<ffffffff829c9f2a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81238b85>] kthread+0x2b5/0x380
> [<ffffffff81097ded>] ret_from_fork+0x2d/0x70
> [<ffffffff810034d1>] 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:
> [<ffffffff817ec023>] __kmalloc_node_track_caller+0x53/0x150
> [<ffffffff82995590>] kvasprintf+0xb0/0x130
> [<ffffffff83f713b1>] kobject_set_name_vargs+0x41/0x110
> [<ffffffff8304ac1b>] dev_set_name+0xab/0xe0
> [<ffffffffa02388a2>] fpga_region_register_full+0x312/0x430 [fpga_region]
> [<ffffffffa0228e47>] 0xffffffffa0228e47
> [<ffffffff829c479d>] kunit_try_run_case+0xdd/0x250
> [<ffffffff829c9f2a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81238b85>] kthread+0x2b5/0x380
> [<ffffffff81097ded>] ret_from_fork+0x2d/0x70
> [<ffffffff810034d1>] 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:
> [<ffffffff817ebad7>] kmalloc_trace+0x27/0xa0
> [<ffffffff83056d7a>] device_add+0xa2a/0x15e0
> [<ffffffffa02388b1>] fpga_region_register_full+0x321/0x430 [fpga_region]
> [<ffffffffa0228e47>] 0xffffffffa0228e47
> [<ffffffff829c479d>] kunit_try_run_case+0xdd/0x250
> [<ffffffff829c9f2a>] kunit_generic_run_threadfn_adapter+0x4a/0x90
> [<ffffffff81238b85>] kthread+0x2b5/0x380
> [<ffffffff81097ded>] ret_from_fork+0x2d/0x70
> [<ffffffff810034d1>] ret_from_fork_asm+0x11/0x20
>
> Fixes: 64a5f972c93d ("fpga: add an initial KUnit suite for the FPGA Region")
> Signed-off-by: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
> ---
> 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);
> }
>
> /*
