Messages in this thread | | | From | Dan Williams <> | Date | Tue, 28 Jun 2016 09:33:10 -0700 | Subject | Re: [RESEND PATCH] x86/mm: only allow memmap=XX!YY over existing RAM |
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On Tue, Jun 28, 2016 at 1:31 AM, Yigal Korman <yigal@plexistor.com> wrote: > Before this patch, passing a range that is beyond the physical memory > range will succeed, the user will see a /dev/pmem0 and will be able to > access it. Reads will always return 0 and writes will be silently > ignored. > > I've gotten more than one bug report about mkfs.{xfs,ext4} or nvml > failing that were eventually tracked down to be wrong values passed to > memmap. > > This patch prevents the above issue by instead of adding a new memory > range, only update a RAM memory range with the PRAM type. This way, > passing the wrong memmap will either not give you a pmem at all or give > you a smaller one that actually has RAM behind it. > > And if someone still needs to fake a pmem that doesn't have RAM behind > it, they can simply do memmap=XX@YY,XX!YY. > > Signed-off-by: Yigal Korman <yigal@plexistor.com> > Acked-by: Dan Williams <dan.j.williams@intel.com> > Acked-by: Johannes Thumshirn <jthumshirn@suse.de> > Tested-by: Boaz Harrosh <boaz@plexistor.com> > ---
I have some other libnvdimm fixes heading upstream shortly if x86 folks just want to ack this one...
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