From: Jinjie Ruan <ruanjinjie@huawei.com>
To: <linux-fpga@vger.kernel.org>, Moritz Fischer <mdf@kernel.org>,
Wu Hao <hao.wu@intel.com>, Xu Yilun <yilun.xu@intel.com>,
Tom Rix <trix@redhat.com>, Marco Pagani <marpagan@redhat.com>
Cc: <ruanjinjie@huawei.com>
Subject: [PATCH] fpga: Fix memory leak for fpga_region_test_class_find()
Date: Sat, 7 Oct 2023 17:43:21 +0800 [thread overview]
Message-ID: <20231007094321.3447084-1-ruanjinjie@huawei.com> (raw)
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
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@huawei.com>
---
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);
}
/*
--
2.34.1
next reply other threads:[~2023-10-07 9:45 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-07 9:43 Jinjie Ruan [this message]
2023-10-09 12:03 ` [PATCH] fpga: Fix memory leak for fpga_region_test_class_find() Marco Pagani
2023-10-12 5:05 ` Xu Yilun
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