Hi Mike,
> -----Original Message-----
> From: linux-rdma-owner@xxxxxxxxxxxxxxx <linux-rdma-
> owner@xxxxxxxxxxxxxxx> On Behalf Of Marciniszyn, Mike
> Sent: Wednesday, April 17, 2019 1:56 PM
> To: Leon Romanovsky <leonro@xxxxxxxxxxxx>
> Cc: linux-rdma@xxxxxxxxxxxxxxx
> Subject: new trace in RDMA next
>
> Leon,
>
> We seem to be getting a new trace with the RDMA for-next patches.
>
> Here is the trace:
>
> systemd: Starting Hostname Service...
> kobject (00000000b8a5bae6): tried to init an initialized object, something is
> seriously wrong.
> CPU: 68 PID: 2098 Comm: (ostnamed) Not tainted 5.1.0-rc4 #1
>
> Call Trace:
> dump_stack+0x5a/0x73
> kobject_init+0x74/0x80
> kobject_init_and_add+0x35/0xb0
> hfi1_create_port_files+0x6e/0x3c0 [hfi1]
> ib_setup_port_attrs+0x43b/0x560 [ib_core]
> add_one_compat_dev+0x16a/0x230 [ib_core]
> rdma_dev_init_net+0x110/0x160 [ib_core]
> ops_init+0x38/0xf0
> setup_net+0xcf/0x1e0
> copy_net_ns+0xb7/0x130
> create_new_namespaces+0x11a/0x1b0
> unshare_nsproxy_namespaces+0x55/0xa0
> ksys_unshare+0x1a7/0x340
> __x64_sys_unshare+0xe/0x20
> do_syscall_64+0x5b/0x180
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> It seems the core is calling init_port(hfi1_create_port_files) twice, the first
> during ib_register_device() and the second from the stack above.
>
> There is a comment in add_one_compat_dev() noting the race:
>
> /*
> * The first of init_net() or ib_register_device() to take the
> * compat_devs_mutex wins and gets to add the device. Others will wait
> * for completion here.
> */
> mutex_lock(&device->compat_devs_mutex);
> cdev = xa_load(&device->compat_devs, rnet->id); if (cdev) {
> ret = 0;
> goto done;
> }
>
> I don't see any xa_store() to compat_devs or use of the mutex in the
> ib_register_device() path?
>
The issue is not with xa_store or lock.
Issue is that hfi1_create_port_files() is trying to create sysfs files out ppd->sc2vl_kobj, which is already initialized during ib_register_device().
For every net ns, my patches are adding compat devices which probably shouldn't invoke init_port for those compat devices as it not meaningful.
Attached patch should fix it.
Can you please test it? I do not have hfi hw.
I will inline the patch, in case attachment doesn't work.
> Is this a known issue?
>
> Mike
Attachment:
0001-RDMA-core-Do-not-invoke-init_port-on-compat-devices.patch
Description: 0001-RDMA-core-Do-not-invoke-init_port-on-compat-devices.patch
