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
