On Mon, Aug 2, 2021 at 8:47 AM Leon Romanovsky <leon@xxxxxxxxxx> wrote: > > On Fri, Jul 30, 2021 at 03:18:24PM +0200, Jack Wang wrote: > > From: Gioh Kim <gi-oh.kim@xxxxxxxxx> > > > > If the client tries to create a path with name "ctl", > > the server tries to creates /sys/devices/virtual/rtrs-server/ctl/. > > Then server generated below error because there is already ctl directory > > which manages some setup of the server. > > > > sysfs: cannot create duplicate filename '/devices/virtual/rtrs-server/ctl' > > Workqueue: ib-comp-wq ib_cq_poll_work [ib_core] > > Call Trace: > > dump_stack+0x50/0x63 > > sysfs_warn_dup.cold+0x17/0x24 > > sysfs_create_dir_ns+0xb6/0xd0 > > kobject_add_internal+0xa6/0x2a0 > > kobject_add+0x7e/0xb0 > > ? _cond_resched+0x15/0x30 > > device_add+0x121/0x640 > > rtrs_srv_create_sess_files+0x18f/0x1f0 [rtrs_server] > > ? __alloc_pages_nodemask+0x16c/0x2b0 > > ? kmalloc_order+0x7c/0x90 > > ? kmalloc_order_trace+0x1d/0xa0 > > ? rtrs_iu_alloc+0x17e/0x1bf [rtrs_core] > > rtrs_srv_info_req_done+0x417/0x5b0 [rtrs_server] > > ? __switch_to_asm+0x40/0x70 > > __ib_process_cq+0x76/0xd0 [ib_core] > > ib_cq_poll_work+0x26/0x80 [ib_core] > > process_one_work+0x1df/0x3a0 > > worker_thread+0x4a/0x3c0 > > kthread+0xfb/0x130 > > ? process_one_work+0x3a0/0x3a0 > > ? kthread_park+0x90/0x90 > > ret_from_fork+0x1f/0x40 > > kobject_add_internal failed for ctl with -EEXIST, don't try to register things with the same name in the same directory. > > rtrs_server L178: device_add(): -17 > > > > This patch checks the path name and disconnect on server to prevent > > the kernel error. > > > > Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxx> > > Signed-off-by: Jack Wang <jinpu.wang@xxxxxxxxx> > > --- > > drivers/infiniband/ulp/rtrs/rtrs-srv.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/infiniband/ulp/rtrs/rtrs-srv.c b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > index cd9a4ccf4c28..b814a6052cf1 100644 > > --- a/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > +++ b/drivers/infiniband/ulp/rtrs/rtrs-srv.c > > @@ -758,6 +758,14 @@ static bool exist_sessname(struct rtrs_srv_ctx *ctx, > > struct rtrs_srv_sess *sess; > > bool found = false; > > > > + /* > > + * Session name "ct" is not allowed because > > + * /sys/devices/virtual/rtrs-server/ctl already exists > > + * for setup management. > > + */ > > + if (!strcmp(sessname, "ctl")) > > + return true; > > Why does it have special treatment? rtrs-server creates a folder named ctl when the module is modprob'ed. When a session is established, a folder of the session name is created at the same location, which would hold sysfs entries such as clt_hostname, path details, queue_depth, etc. Due to this conflict of names, creation of session with that name is not possible. So this gracefully fails the connection establishment instead of a stack trace. > And what will happen if user supplies "." or ".."? Weirdly enough, this succeeds. I tried, and the session creation succeeds, and there is a hidden entry in the rtrs-server folder, but it cannot be accessed through bash. > Does rtrs receive this session name from the other side in the network? Yes. This string is entered by the user while creating the session. > > Thanks
