Date: Fri, 30 May 2003 10:30:29 -0700 From: Marcel Moolenaar <marcel@xcllnt.net> To: Alan Robinson <alan.robinson@fujitsu-siemens.com> Cc: freebsd-ia64@freebsd.org Subject: Re: /dev/kmem read return value is double requested value Message-ID: <20030530173029.GB568@dhcp01.pn.xcllnt.net> In-Reply-To: <20030530132408.A3690@fujitsu-siemens.com> References: <20030530132408.A3690@fujitsu-siemens.com>
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On Fri, May 30, 2003 at 01:24:08PM +0200, Alan Robinson wrote: > > I was playing with a user-land program that read some data out > of the kernel memory and noticed that the read() return value was > twice what I was expecting. I think the error is in the mmrw() function > in file sys/ia64/ia64/mem.c, removing the following lines seems to > fix the problem. > > iov->iov_base = (char *)iov->iov_base + c; > iov->iov_len -= c; > uio->uio_offset += c; > uio->uio_resid -= c; > > I had a little look at some of the other sys/ARCH/ARCH/mem.c and some others > seem to contain the same code so I might be wrong, then again so might the > ARCHs. If you see behaviour that's not particular to ia64, it's probably better to post to arch@ or current@. More people hang out there, so there's a bigger chance you get replies. I don't think there's anything wrong with the lines you think we need to remove. > Note that the actual data transfered is OK, just the read() return value > and the /dev/kmem file offset are wrong after returning from the read(). It helps if you demonstrate the behaviour with some trivial test program that people can run too. > PS is this the reason there is no gdb ? No. There's currenty no gdb because it hasn't been ported yet. -- Marcel Moolenaar USPA: A-39004 marcel@xcllnt.net
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