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: [email protected] Cc: [email protected] Cc: [email protected] Cc: Andrew Morton <[email protected]> Cc: Michal Hocko <[email protected]> Cc: Vlastimil Babka <[email protected]> Cc: Mike Rapoport <[email protected]> Cc: Bjorn Helgaas <[email protected]> Cc: Jonathan Cameron <[email protected]> Cc: David Rientjes <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: "H. Peter Anvin" <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Michael Ellerman <[email protected]> -- 2.7.4
