> -----Original Message----- > From: Mohammed Gamal <mgamal@xxxxxxxxxx> > Sent: Tuesday, January 14, 2020 8:10 AM > To: linux-hyperv@xxxxxxxxxxxxxxx; Stephen Hemminger > <sthemmin@xxxxxxxxxxxxx>; Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>; > netdev@xxxxxxxxxxxxxxx > Cc: KY Srinivasan <kys@xxxxxxxxxxxxx>; sashal@xxxxxxxxxx; vkuznets > <vkuznets@xxxxxxxxxx>; cavery <cavery@xxxxxxxxxx>; linux- > kernel@xxxxxxxxxxxxxxx; Mohammed Gamal <mgamal@xxxxxxxxxx> > Subject: [PATCH v2] hv_netvsc: Fix memory leak when removing rndis device > > kmemleak detects the following memory leak when hot removing a network > device: > > unreferenced object 0xffff888083f63600 (size 256): > comm "kworker/0:1", pid 12, jiffies 4294831717 (age 1113.676s) > hex dump (first 32 bytes): > 00 40 c7 33 80 88 ff ff 00 00 00 00 10 00 00 00 .@.3............ > 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... > backtrace: > [<00000000d4a8f5be>] rndis_filter_device_add+0x117/0x11c0 [hv_netvsc] > [<000000009c02d75b>] netvsc_probe+0x5e7/0xbf0 [hv_netvsc] > [<00000000ddafce23>] vmbus_probe+0x74/0x170 [hv_vmbus] > [<00000000046e64f1>] really_probe+0x22f/0xb50 > [<000000005cc35eb7>] driver_probe_device+0x25e/0x370 > [<0000000043c642b2>] bus_for_each_drv+0x11f/0x1b0 > [<000000005e3d09f0>] __device_attach+0x1c6/0x2f0 > [<00000000a72c362f>] bus_probe_device+0x1a6/0x260 > [<0000000008478399>] device_add+0x10a3/0x18e0 > [<00000000cf07b48c>] vmbus_device_register+0xe7/0x1e0 [hv_vmbus] > [<00000000d46cf032>] vmbus_add_channel_work+0x8ab/0x1770 [hv_vmbus] > [<000000002c94bb64>] process_one_work+0x919/0x17d0 > [<0000000096de6781>] worker_thread+0x87/0xb40 > [<00000000fbe7397e>] kthread+0x333/0x3f0 > [<000000004f844269>] ret_from_fork+0x3a/0x50 > > rndis_filter_device_add() allocates an instance of struct rndis_device which > never gets deallocated as rndis_filter_device_remove() sets net_device- > >extension which points to the rndis_device struct to NULL, leaving the > rndis_device dangling. > > Since net_device->extension is eventually freed in free_netvsc_device(), we > refrain from setting it to NULL inside rndis_filter_device_remove() > > Signed-off-by: Mohammed Gamal <mgamal@xxxxxxxxxx> > --- > drivers/net/hyperv/rndis_filter.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c > index 857c4bea451c..e66d77dc28c8 100644 > --- a/drivers/net/hyperv/rndis_filter.c > +++ b/drivers/net/hyperv/rndis_filter.c > @@ -1443,8 +1443,6 @@ void rndis_filter_device_remove(struct hv_device > *dev, > /* Halt and release the rndis device */ > rndis_filter_halt_device(net_dev, rndis_dev); > > - net_dev->extension = NULL; > - > netvsc_device_remove(dev); Reviewed-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
