This bug is original reported at https://lore.kernel.org/patchwork/patch/1020838/ In a short word, this bug should affect all archs, where a machine with a numa-node having no memory, if nr_cpus prevents the instance of nodeA, and the device on nodeA tries to allocate memory with device->numa_node info. And node_zonelist(preferred_nid, gfp_mask) will panic due to uninstanced nodeA.
And there are two alternative methods to fix it. -1st. Fix it in mm system -2nd. Fix it in all archs independently, by online all possible nodes. Originaly, I tries to fix it by the 1st method, while Michal suggests the 2nd one. This series [1-2/3] tries to resolve some defect in v1, pointed out by Michal. For discussion purpose, I send [3/3] in this thread, which tries to show e.g of the 2nd method on powerpc platform. For x86, I still help Michal to verify his patch on my test machine, please see: https://lore.kernel.org/patchwork/comment/1208479/ https://lore.kernel.org/patchwork/comment/1210452/ It has already cost a little long time to find a solution, cc x86 and ppc mailing list and hope their maintainers to give some suggestion to speed up the final solution. Pingfan Liu (3): mm/numa: change the topo of build_zonelist_xx() mm/numa: build zonelist when alloc for device on offline node powerpc/numa: make all possible node be instanced against NULL reference in node_zonelist() arch/powerpc/mm/numa.c | 13 ++++++-- include/linux/gfp.h | 10 +++++- mm/page_alloc.c | 85 ++++++++++++++++++++++++++++++++++++-------------- 3 files changed, 81 insertions(+), 27 deletions(-) Cc: linuxppc-dev@lists.ozlabs.org Cc: x...@kernel.org Cc: linux-ker...@vger.kernel.org Cc: Andrew Morton <a...@linux-foundation.org> Cc: Michal Hocko <mho...@suse.com> Cc: Vlastimil Babka <vba...@suse.cz> Cc: Mike Rapoport <r...@linux.vnet.ibm.com> Cc: Bjorn Helgaas <bhelg...@google.com> Cc: Jonathan Cameron <jonathan.came...@huawei.com> Cc: David Rientjes <rient...@google.com> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ingo Molnar <mi...@redhat.com> Cc: Borislav Petkov <b...@alien8.de> Cc: "H. Peter Anvin" <h...@zytor.com> Cc: Benjamin Herrenschmidt <b...@kernel.crashing.org> Cc: Paul Mackerras <pau...@samba.org> Cc: Michael Ellerman <m...@ellerman.id.au> -- 2.7.4
