Messages in this thread | | | Subject | Re: 2.6.8.1-mm4 | From | Alan Cox <> | Date | Mon, 23 Aug 2004 19:31:15 +0100 |
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On Llu, 2004-08-23 at 19:21, Tomasz Torcz wrote: > >- This kernel has an x86 patch which alters the copy_*_user() functions so > > they will return -EFAULT on a fault rather than the number of bytes which > > remain to be copied. This is a bit of an experiment, because this seems to > > be the preferred API for those functions. It's a see-what-breaks thing. > > > > Things appear to broke. Sometimes kernel starts to spit page allocation > failures into log for few minutes, despite memory beeing available:
The kernel relies on copy_from_user returning the number of bytes copied so no suprise there. In fact if it returns -EFAULT and you've not reworked all the drivers (including out of kernel serial drivers in particular) you get a security hole because you can move the buffer pointers backwards.
Other code uses it to decide what object was passed for compatibility too.
Alan
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