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From: Vinit Agnihotri <vinita@ryussi.com>
To: linux-rdma@vger.kernel.org
Subject: Unable to register memory, ibv_reg_mr returning EACCESS
Date: Fri, 8 Nov 2019 11:02:39 +0530	[thread overview]
Message-ID: <06a5eab8-6341-850a-46cd-8dfedfb63da9@ryussi.com> (raw)

Hi,

we have a userspace server which would allow user to access files using 
his/her own credentials via UID mapping.

while we are running server as root user, but to in order to honor posix 
mappings, we use  setfsgid()/setfssid() before

accessing any file and restore them back to user access. However when we 
try to ibv_reg_mr() EACCESS is returned.

We are ensuring to be root before we call to ibv_reg_mr(), yet it keeps 
failing.

While going through libibverbs sources we realize EACCESS might be 
returned by this call:

if (write(pd->context->cmd_fd, cmd, cmd_size) != cmd_size)
         return errno;


As we are ensuring that setfsgid()/setfssid() are set to root before we 
call to ibv_reg_mr(), why EACCESS is still returned?

Since these calls are thread specific only why it should affect entire 
process?

Can anyone provide any insight into this behavior?


Thanks & Regards,

Vinit.



                 reply	other threads:[~2019-11-08  5:32 UTC|newest]

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