* Kernel memory leak on CDC-ACM device plug/unplug
@ 2018-09-19 14:11 Romain Izard
2018-09-19 20:32 ` Greg KH
2018-09-21 8:08 ` Oliver Neukum
0 siblings, 2 replies; 5+ messages in thread
From: Romain Izard @ 2018-09-19 14:11 UTC (permalink / raw)
To: linux-arm-kernel
While trying to debug a memory leak problem, I encountered the following
problem:
After plugging/unplugging an USB CDC-ACM device, kmemleak reports multiple
copies of the following leak. It is not necessary to open the port for the
leak to happen.
unreferenced object 0xddbfd500 (size 128):
comm "kworker/0:3", pid 675, jiffies 69734 (age 916.580s)
hex dump (first 32 bytes):
01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
00 00 00 00 00 00 00 00 00 00 00 00 1c d5 bf dd ................
backtrace:
[<da0194da>] acm_probe+0x868/0xc3c
[<cc72c809>] usb_probe_interface+0x11c/0x274
[<bbce212c>] driver_probe_device+0x22c/0x320
[<544a5b43>] bus_for_each_drv+0x58/0xb8
[<fe5944dc>] __device_attach+0xd0/0x138
[<d807c1e5>] bus_probe_device+0x84/0x8c
[<16645f2c>] device_add+0x3cc/0x5c0
[<80c11c88>] usb_set_configuration+0x448/0x7b0
[<76bdbcdf>] generic_probe+0x2c/0x78
[<bbce212c>] driver_probe_device+0x22c/0x320
[<544a5b43>] bus_for_each_drv+0x58/0xb8
[<fe5944dc>] __device_attach+0xd0/0x138
[<d807c1e5>] bus_probe_device+0x84/0x8c
[<16645f2c>] device_add+0x3cc/0x5c0
[<02a49898>] usb_new_device+0x264/0x424
[<865a481b>] hub_event+0xa20/0x1154
For each additional plug/unplug cycle, around 30 such new leaks are created.
Tested on a SAMA5D2 Xplained demo board, with a v4.18.8 kernel.
The CDC-ACM device was another SAMA5D2 device, with a composite profile
including a CDC-ACM port implemented with configfs.
--
Romain Izard
^ permalink raw reply [flat|nested] 5+ messages in thread* Kernel memory leak on CDC-ACM device plug/unplug
2018-09-19 14:11 Kernel memory leak on CDC-ACM device plug/unplug Romain Izard
@ 2018-09-19 20:32 ` Greg KH
2018-09-20 14:17 ` Romain Izard
2018-09-21 8:08 ` Oliver Neukum
1 sibling, 1 reply; 5+ messages in thread
From: Greg KH @ 2018-09-19 20:32 UTC (permalink / raw)
To: linux-arm-kernel
On Wed, Sep 19, 2018 at 04:11:55PM +0200, Romain Izard wrote:
> While trying to debug a memory leak problem, I encountered the following
> problem:
>
> After plugging/unplugging an USB CDC-ACM device, kmemleak reports multiple
> copies of the following leak. It is not necessary to open the port for the
> leak to happen.
>
> unreferenced object 0xddbfd500 (size 128):
> comm "kworker/0:3", pid 675, jiffies 69734 (age 916.580s)
> hex dump (first 32 bytes):
> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
> 00 00 00 00 00 00 00 00 00 00 00 00 1c d5 bf dd ................
> backtrace:
> [<da0194da>] acm_probe+0x868/0xc3c
> [<cc72c809>] usb_probe_interface+0x11c/0x274
> [<bbce212c>] driver_probe_device+0x22c/0x320
> [<544a5b43>] bus_for_each_drv+0x58/0xb8
> [<fe5944dc>] __device_attach+0xd0/0x138
> [<d807c1e5>] bus_probe_device+0x84/0x8c
> [<16645f2c>] device_add+0x3cc/0x5c0
> [<80c11c88>] usb_set_configuration+0x448/0x7b0
> [<76bdbcdf>] generic_probe+0x2c/0x78
> [<bbce212c>] driver_probe_device+0x22c/0x320
> [<544a5b43>] bus_for_each_drv+0x58/0xb8
> [<fe5944dc>] __device_attach+0xd0/0x138
> [<d807c1e5>] bus_probe_device+0x84/0x8c
> [<16645f2c>] device_add+0x3cc/0x5c0
> [<02a49898>] usb_new_device+0x264/0x424
> [<865a481b>] hub_event+0xa20/0x1154
>
> For each additional plug/unplug cycle, around 30 such new leaks are created.
>
> Tested on a SAMA5D2 Xplained demo board, with a v4.18.8 kernel.
> The CDC-ACM device was another SAMA5D2 device, with a composite profile
> including a CDC-ACM port implemented with configfs.
Have you come up with any patches that might resolve this? It's hard to
see what exactly is "leaking" here.
thanks,
greg k-h
^ permalink raw reply [flat|nested] 5+ messages in thread
* Kernel memory leak on CDC-ACM device plug/unplug
2018-09-19 20:32 ` Greg KH
@ 2018-09-20 14:17 ` Romain Izard
0 siblings, 0 replies; 5+ messages in thread
From: Romain Izard @ 2018-09-20 14:17 UTC (permalink / raw)
To: linux-arm-kernel
2018-09-19 22:32 GMT+02:00 Greg KH <gregkh@linuxfoundation.org>:
> On Wed, Sep 19, 2018 at 04:11:55PM +0200, Romain Izard wrote:
>> While trying to debug a memory leak problem, I encountered the following
>> problem:
>>
>> After plugging/unplugging an USB CDC-ACM device, kmemleak reports multiple
>> copies of the following leak. It is not necessary to open the port for the
>> leak to happen.
>>
>> unreferenced object 0xddbfd500 (size 128):
>> comm "kworker/0:3", pid 675, jiffies 69734 (age 916.580s)
>> hex dump (first 32 bytes):
>> 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
>> 00 00 00 00 00 00 00 00 00 00 00 00 1c d5 bf dd ................
>> backtrace:
>> [<da0194da>] acm_probe+0x868/0xc3c
>> [<cc72c809>] usb_probe_interface+0x11c/0x274
>> [<bbce212c>] driver_probe_device+0x22c/0x320
>> [<544a5b43>] bus_for_each_drv+0x58/0xb8
>> [<fe5944dc>] __device_attach+0xd0/0x138
>> [<d807c1e5>] bus_probe_device+0x84/0x8c
>> [<16645f2c>] device_add+0x3cc/0x5c0
>> [<80c11c88>] usb_set_configuration+0x448/0x7b0
>> [<76bdbcdf>] generic_probe+0x2c/0x78
>> [<bbce212c>] driver_probe_device+0x22c/0x320
>> [<544a5b43>] bus_for_each_drv+0x58/0xb8
>> [<fe5944dc>] __device_attach+0xd0/0x138
>> [<d807c1e5>] bus_probe_device+0x84/0x8c
>> [<16645f2c>] device_add+0x3cc/0x5c0
>> [<02a49898>] usb_new_device+0x264/0x424
>> [<865a481b>] hub_event+0xa20/0x1154
>>
>> For each additional plug/unplug cycle, around 30 such new leaks are created.
>>
>> Tested on a SAMA5D2 Xplained demo board, with a v4.18.8 kernel.
>> The CDC-ACM device was another SAMA5D2 device, with a composite profile
>> including a CDC-ACM port implemented with configfs.
>
> Have you come up with any patches that might resolve this? It's hard to
> see what exactly is "leaking" here.
>
I finally found that Linux v4.9 was not affected.
git-bisect gives the following output:
ba8c931ded8d96c8923662099416bc2096644eab is the first bad commit
commit ba8c931ded8d96c8923662099416bc2096644eab
Author: Ladislav Michl <ladis@linux-mips.org>
Date: Fri Nov 18 19:07:08 2016 +0100
cdc-acm: refactor killing urbs
Move urb killing code into separate function and use it
instead of copying that code pattern over.
Signed-off-by: Ladislav Michl <ladis@linux-mips.org>
Acked-by: Oliver Neukum <oneukum@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
:040000 040000 bb64a6003aa575fb459cd64cb63ff0189134db8f
68ad7dc597533eaff2d33c9ac2b23d49906f6551 M drivers
I found a bug in that commit, I'm sending a fix for it.
Best regards
--
Romain Izard
^ permalink raw reply [flat|nested] 5+ messages in thread
* Kernel memory leak on CDC-ACM device plug/unplug
2018-09-19 14:11 Kernel memory leak on CDC-ACM device plug/unplug Romain Izard
2018-09-19 20:32 ` Greg KH
@ 2018-09-21 8:08 ` Oliver Neukum
2018-09-21 10:11 ` Romain Izard
1 sibling, 1 reply; 5+ messages in thread
From: Oliver Neukum @ 2018-09-21 8:08 UTC (permalink / raw)
To: linux-arm-kernel
On Mi, 2018-09-19 at 16:11 +0200, Romain Izard wrote:
> While trying to debug a memory leak problem, I encountered the following
> problem:
>
> After plugging/unplugging an USB CDC-ACM device, kmemleak reports multiple
> copies of the following leak. It is not necessary to open the port for the
> leak to happen.
Hi,
nothing is immediately obvious to me. Could you compile a kernel with
CONFIG_DEBUG_KMEMLEAK?
Regards
Oliver
^ permalink raw reply [flat|nested] 5+ messages in thread
* Kernel memory leak on CDC-ACM device plug/unplug
2018-09-21 8:08 ` Oliver Neukum
@ 2018-09-21 10:11 ` Romain Izard
0 siblings, 0 replies; 5+ messages in thread
From: Romain Izard @ 2018-09-21 10:11 UTC (permalink / raw)
To: linux-arm-kernel
2018-09-21 10:08 GMT+02:00 Oliver Neukum <oneukum@suse.com>:
> On Mi, 2018-09-19 at 16:11 +0200, Romain Izard wrote:
>> While trying to debug a memory leak problem, I encountered the following
>> problem:
>>
>> After plugging/unplugging an USB CDC-ACM device, kmemleak reports multiple
>> copies of the following leak. It is not necessary to open the port for the
>> leak to happen.
>
> Hi,
>
> nothing is immediately obvious to me. Could you compile a kernel with
> CONFIG_DEBUG_KMEMLEAK?
>
The fix for this issue is the following patch:
https://www.spinics.net/lists/linux-usb/msg172850.html
Best regards,
--
Romain Izard
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2018-09-21 10:11 UTC | newest]
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2018-09-19 14:11 Kernel memory leak on CDC-ACM device plug/unplug Romain Izard
2018-09-19 20:32 ` Greg KH
2018-09-20 14:17 ` Romain Izard
2018-09-21 8:08 ` Oliver Neukum
2018-09-21 10:11 ` Romain Izard
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