Messages in this thread | | | Subject | Re: [PATCH] Fix mmap_kmem (was: [question] What's the difference between /dev/kmem and /dev/mem) | From | Alan Cox <> | Date | Wed, 17 Aug 2005 00:33:45 +0100 |
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On Maw, 2005-08-16 at 17:12 -0500, Greg Edwards wrote: > mmap_mem suffers from a lack of proper checks as well. For example, on > Altix page 0 of each node is reserved for prom and a read or write to it > will cause an MCA. mmaping /dev/mem with offset 0 will nicely explode. > Would adding a pfn_valid test in mmap_mem be the best bet, or could we > consolidate the checks currently in mmap_kmem into mmap_mem?
If you use /dev/mem you should know what you are doing. Even with "checks" dd if=/dev/zero of=/dev/mem will do bad things. Trapping obviously bad cases is fine, but complete sanity checking may actually be counter productive.
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