Messages in this thread | | | Date | Tue, 6 Jan 2009 00:54:58 -0500 | From | "Mike Frysinger" <> | Subject | Re: debugfs & vfs file permission issue? |
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On Tue, Jan 6, 2009 at 00:48, Greg KH wrote: > On Mon, Jan 05, 2009 at 09:57:07PM -0500, Robin Getz wrote: >> On 2.6.28-rc2, If I create a debugfs file with >> >> debugfs_create_x16("SPORT1_TX", 0200 , parent, 0xFFC00910); > > Um, are you are passing in a pointer to a known memory location > properly? Why would it be ok for the kernel to directly read that > location?
it's a nommu system and the 0xffc00000+ addresses are always available
>> Although the file shows up as write only (no read): >> >> root:/> ls -l /sys/kernel/debug/blackfin/SPORT/SPORT1_TX >> --w------- 1 root root 0 Jan 1 >> 2007 /sys/kernel/debug/blackfin/SPORT/SPORT1_TX >> >> root:/> cat /sys/kernel/debug/blackfin/SPORT/SPORT1_TX >> >> Still works - and causes the read to occur, which crashes :( > > You're root, you can do anything :)
any thoughts on how to declare debugfs files that are read or write only ? we'll have to add new helper functions or have it be a parameter or declare our own debugfs file ? -mike
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