Messages in this thread | | | Date | Fri, 9 Mar 2012 14:02:44 -0800 | From | Matt Helsley <> | Subject | Re: [RFC] c/r: prctl: Add ability to set new mm_struct::exe_file v3 |
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On Fri, Mar 09, 2012 at 07:42:24PM +0400, Cyrill Gorcunov wrote: > On Fri, Mar 09, 2012 at 04:21:22PM +0100, Oleg Nesterov wrote:
<snip>
> > Just one note for the record, prctl_set_mm_exe_file() does > > > > if (mm->num_exe_file_vmas) > > return -EBUSY; > > > > We could do > > > > if (mm->exe_file) > > return -EBUSY; > > > > This way "because this feature is a special to C/R" becomes > > really true. IOW, you can't do PR_SET_MM_EXE_FILE twice. > > > > Sure, i'll make it this way. Thanks a lot, Oleg!!!
Sorry about the other email -- hadn't full caught up on this thread. This is even better, yes.
Of course I'd prefer it if there was a way to keep num_exe_file_vmas correct and not special-case c/r. The first approximation of a solution might be to increment the count whenever a new mmap filp == mm->exe_file and decrement on unmap. I think there are a bunch of details needed to make that work but my feeling is it's do-able. Have you investigated this already and rejected it for some reason (did I miss that discussion somehow?)?
Cheers, -Matt Helsley
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