From: Mohammed Gamal mgamal@redhat.com
[ Upstream commit 536dc5df2808efbefc5acee334d3c4f701790ec0 ]
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@redhat.com Reviewed-by: Haiyang Zhang haiyangz@microsoft.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/hyperv/rndis_filter.c | 2 -- 1 file changed, 2 deletions(-)
--- a/drivers/net/hyperv/rndis_filter.c +++ b/drivers/net/hyperv/rndis_filter.c @@ -1331,8 +1331,6 @@ void rndis_filter_device_remove(struct h /* Halt and release the rndis device */ rndis_filter_halt_device(rndis_dev);
- net_dev->extension = NULL; - netvsc_device_remove(dev); }