The title is a bit long. :-) On Oct 19, 2012, at 3:30 PM, Gutierrez, Samuel K wrote:
> Hi Chris, > > Thanks for all the info. Below is what can go into the FAQ. Any suggestions? > > I'm trying to use the Cross Memory Attach (CMA) capability within the > shared-memory (sm) BTL, but am getting: "mca_btl_sm_get_sync: process_vm_readv > failed: 1." Why am I seeing this error message? > > This may be due to insufficient permissions. CMA's usage requirements are > exactly the same as those required to successfully perform a ptrace wtih > PTRACE_ATTACH. > > On some systems, a modification to /etc/sysctl.d/10-ptrace.conf is required. > > Change: > kernel.yama.ptrace_scope = 1 > > to > > kernel.yama.ptrace_scope = 0 > > and restart your system so the change can take effect. > > Thanks, > > Sam > ________________________________________ > From: devel-boun...@open-mpi.org [devel-boun...@open-mpi.org] on behalf of > Christopher Yeoh [cy...@ozlabs.org] > Sent: Thursday, October 18, 2012 5:57 PM > To: de...@open-mpi.org > Subject: Re: [OMPI devel] Cross Memory Attach: What am I Missing? > > Hi Sam, > > On Thu, 18 Oct 2012 15:08:59 +0000 > "Gutierrez, Samuel K" <sam...@lanl.gov> wrote: >> >> I really appreciate your pointing me in the right direction. It turns >> out that on this particular system had /etc/sysctl.d/10-ptrace.conf >> was set to 1. Changing this to 0 fixed the problem. I'm not sure if >> this is the best way of getting things to work, but is sufficient for >> my purposes. > > Yes I think this is the best way to do it. The kernel side > implementation of CMA does the same permission checking as as ptrace > (checks to see if PTRACE_MODE_ATTACH would be permitted). A value of 1 > in that config file only allows you to ptrace direct child processes, > whereas a 0 removes that restriction. > > You still need to either have CAP_SYS_PTRACE (eg am probably root) or > have the same UID/GID as the target. So from a security point of view > the only extra risk you have exposed your system to are bugs that may > exist in the ptrace or CMA implementations. > > Regards, > > Chris > >> Thanks! >> >> Sam >> ________________________________ >> From: devel-boun...@open-mpi.org [devel-boun...@open-mpi.org] on >> behalf of George Bosilca [bosi...@icl.utk.edu] Sent: Thursday, >> October 18, 2012 7:44 AM To: Open MPI Developers >> Subject: Re: [OMPI devel] Cross Memory Attach: What am I Missing? >> >> Check the permissions granted by pam. Look in the /etc/security to >> check for any type of restrictions. >> >> george. >> >> >> On Oct 17, 2012, at 23:30 , "Gutierrez, Samuel K" >> <sam...@lanl.gov<mailto:sam...@lanl.gov>> wrote: >> >> Hi, >> >> I'm trying to run with CMA support, but process_vm_readv is failing >> with EPERM when trying to use it as a regular user (everything seems >> to work fine as root). I've looked around for some solutions, but I >> can't seem to find what I'm looking for. The documentation states >> that the target and source processes need to have the same GID and >> UID to work properly. It appears that they do, so my feeling is that >> I'm missing something. >> >> Any help is greatly appreciated. >> >> Thanks, >> >> Sam >> _______________________________________________ >> devel mailing list >> de...@open-mpi.org<mailto:de...@open-mpi.org> >> http://www.open-mpi.org/mailman/listinfo.cgi/devel >> > -- > cy...@au1.ibm.com > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel > > _______________________________________________ > devel mailing list > de...@open-mpi.org > http://www.open-mpi.org/mailman/listinfo.cgi/devel -- Jeff Squyres jsquy...@cisco.com For corporate legal information go to: http://www.cisco.com/web/about/doing_business/legal/cri/
