Re: 3.12-rc3 memory leak in module memstick

From: Catalin Marinas
Date: Tue Oct 01 2013 - 10:05:36 EST


On 30 September 2013 18:51, Larry Finger <Larry.Finger@xxxxxxxxxxxx> wrote:
> On 3.12-rc3, I detected a memory leak in module memstick. The kmemleak
> results are listed below. The second output is after memstick was unloaded,
> which shows that it is not a false positive from kmemleak.
>
> larrylap:~ # echo scan > /sys/kernel/debug/kmemleak
> larrylap:~ # cat /sys/kernel/debug/kmemleak
> unreferenced object 0xffff8800ae85c190 (size 16):
> comm "kworker/u4:3", pid 685, jiffies 4294916336 (age 2831.760s)
> hex dump (first 16 bytes):
> 6d 65 6d 73 74 69 63 6b 30 00 00 00 00 00 00 00 memstick0.......
> backtrace:
> [<ffffffff8146a0d1>] kmemleak_alloc+0x21/0x50
> [<ffffffff81160720>] __kmalloc_track_caller+0x160/0x2f0
> [<ffffffff81237b9b>] kvasprintf+0x5b/0x90
> [<ffffffff8122c0c1>] kobject_set_name_vargs+0x21/0x60
> [<ffffffff812e7f5c>] dev_set_name+0x3c/0x40
> [<ffffffffa02bf918>] memstick_check+0xb8/0x340 [memstick]
> [<ffffffff81069862>] process_one_work+0x1d2/0x670
> [<ffffffff8106a88a>] worker_thread+0x11a/0x370
> [<ffffffff81072ea6>] kthread+0xd6/0xe0
> [<ffffffff81478bbc>] ret_from_fork+0x7c/0xb0

The leak is most likely coming from memstick_alloc_card() on the error
path. Commit 0252c3b4f0 (memstick: struct device - replace bus_id with
dev_name(), dev_set_name()) sets allocates the device name but 'card'
is freed on the error path without freeing the name.

--
Catalin
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