Hi Sam, On Fri, 19 Oct 2012 19:30:16 +0000 "Gutierrez, Samuel K" <sam...@lanl.gov> wrote: > > Thanks for all the info. Below is what can go into the FAQ. Any > suggestions? >
Sounds good. One thing that might be worth adding is a suggestion to look at SE Linux as well if the ptrace_scope setting doesn't work. I don't know the details but I think Fedora might now disable ptrace by default using an SE Linux setting. Regards, Chris > 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 > -- cy...@ozlabs.org
