Re: [PATCH for-rc 6/7] IB/hfi1: Remove overly conservative VM_EXEC flag check

[Jason Gunthorpe <jgg@ziepe.ca>]

On Thu, Jan 17, 2019 at 12:42:04PM -0800, Dennis Dalessandro wrote:
> From: Michael J. Ruhl <michael.j.ruhl@intel.com>
> 
> Applications that use the stack for execution purposes cause
> PSM jobs to fail during mmap().
> 
> Both Fortran (non-standard format parsing) and C (callback
> functions located in the stack) applications can be written
> such that stack execution is required.
> 
> Because of this the EXECSTACK bit can be automatically set at link
> time for any application.
> 
> On application load, the ELF loader evaluates the EXECSTACK bit
> for the application and it's linked libraries.  It will set the
> process VM flags to allow the stack to include the VM_EXEC bit
> if the EXECSTACK bit is set.  This flag is propagated to the
> driver during the mmap() call in the vma flag bits.
> 
> Checking for this bit and failing the request with EPERM is overly
> conservative and will break any PSM application that has the bit set.
> 
> Remove the VM_EXEC flag from the check.
> 
> Cc: <stable@vger.kernel.org> #v4.14+
> Fixes: 12220267645c ("IB/hfi: Protect against writable mmap")
> Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com>
> Reviewed-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@intel.com>
> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
> ---
>  drivers/infiniband/hw/hfi1/file_ops.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)

applied to for-next

Thanks,
Jason