Messages in this thread | | | From | Clemens Kolbitsch <> | Subject | Re: Forbid deletion of memory mappings | Date | Thu, 30 Aug 2007 23:41:09 +0200 |
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On Thursday 30 August 2007 23:34:52 you wrote: > On Thu, 30 Aug 2007, Clemens Kolbitsch wrote: > > is there no way to tell the kernel, that a certain mapping must not be > > removed, no matter what (except of course an explicit call to sys_unmap, > > of course)? > > I don't seem to get what is the issue here. Your mapping is not removed, > only the VMAs are merged together into one larger VMA if they have > neighbouring address ranges and compatible protection bits. See > vma_merge().
the thing is that they are not. the kernel chooses to REPLACE my mapping.
consider the user-space code:
mmap(0xaaaa0000, 0x3000, MAP_FIXED, ...); mmap(0xaaaa1000, 0x4000, MAP_FIXED, ...);
here, the second call to mmap will shorten the first mapping to 0x1000 bytes and create one big vma with size 0x5000 bytes.
is there a way to tell it that the second mmap MUST fail?
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