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Chris Wedgwood <chris@cybernet.co.nz> said: [...] > Basically... if you pass bogus addresses and pointers to the kernel, > depending on what OS and version you are running, you might get an > EFAULT and you might not. This is (somewhat) OK. > There is no wrong or right way - and no simple fix other than DON'T > PASS BOGUS POINTERS TO THE KERNEL. You should try not to, but the kernel _can't_ just believe in your guarantees. For all it knows, you might be Kubys ;-) > In linux 2.0.x and more traditional kernels, the verify_area checks > will determine the address of bogus before reading or writing any > data, under 2.1.x and I think also NetBSD, if the start of the memory > range you spcific is legitimate, some data will be read and written. In the 2.1.xx kernels this mechanism was replaced by a nifty, no-overhead use of the MM to do the same thing: No checks, but if an illegal access is attempted, the kernel gets an exception. Look at your nearest Documentation directory. -- Dr. Horst H. von Brand mailto:vonbrand@inf.utfsm.cl Departamento de Informatica Fono: +56 32 654431 Universidad Tecnica Federico Santa Maria +56 32 654239 Casilla 110-V, Valparaiso, Chile Fax: +56 32 797513 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||||
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