Dan Williams <[email protected]> writes: > In commit ec776ef6bbe1 "x86/mm: Add support for the non-standard > protected e820 type" Christoph references the original patch I wrote > implementing pmem support. The intent of the 'max_pfn' changes in that > commit were to enable persistent memory ranges to be covered by the > struct page memmap by default. However, that approach was abandoned > when Christoph ported the patches [1], and that functionality has since > been replaced by devm_memremap_pages(). > > In the meantime, this max_pfn manipulation is confusing kdump [2] that > assumes that everything covered by the max_pfn is "System RAM". This > results in kdump hanging or crashing.
That was my assumption, I'm not certain that the kdump code is assuming the pmem region is usable as RAM. The end result is a hung kdump kernel. > [1]: https://lists.01.org/pipermail/linux-nvdimm/2015-March/000348.html > [2]: https://bugzilla.redhat.com/show_bug.cgi?id=1351098 > > Cc: Christoph Hellwig <[email protected]> > Cc: Ross Zwisler <[email protected]> > Cc: Andrew Morton <[email protected]> > Cc: Boaz Harrosh <[email protected]> > Cc: H. Peter Anvin <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: Ingo Molnar <[email protected]> > Reported-by: Zhang Yi <[email protected]> > Reported-by: Jeff Moyer <[email protected]> > Tested-by: Zhang Yi <[email protected]> I actually did the testing. You can leave that line as is, though, as I'm sure Yi will also test it. :) > Fixes: ec776ef6bbe1 ("x86/mm: Add support for the non-standard protected e820 > type") > Signed-off-by: Dan Williams <[email protected]> Reviewed-by: Jeff Moyer <[email protected]> Thanks, Dan! -Jeff
