Hi, I am getting BUG_ON in migration_entry_to_page() with 4.1.0-rc2 kernel on powerpc system which has 512 CPUs (64 cores - 16 nodes) and 1.6 TB memory. We can easily recreate this issue with kernel compile (make -j500). But I could not reproduce with numa_balancing=disable.
------------[ cut here ]------------ kernel BUG at include/linux/swapops.h:134! cpu 0x154: Vector: 700 (Program Check) at [c00009cf365c7610] pc: c00000000021e48c: remove_migration_pte+0x29c/0x450 lr: c00000000021e47c: remove_migration_pte+0x28c/0x450 sp: c00009cf365c7890 msr: 8000000002029033 current = 0xc00009cf36525fc0 paca = 0xc00000000e80fa00 softe: 0 irq_happened: 0x01 pid = 244969, comm = cc1 kernel BUG at include/linux/swapops.h:134! enter ? for help [c00009cf365c7960] c0000000001f3228 rmap_walk+0x348/0x460 [c00009cf365c7a10] c0000000008d8804 remove_migration_ptes+0x6c/0x84 [c00009cf365c7ab0] c000000000220d2c migrate_pages+0xaac/0xd20 [c00009cf365c7c00] c0000000002218cc migrate_misplaced_page+0x12c/0x210 [c00009cf365c7ca0] c0000000001e613c handle_mm_fault+0xa4c/0x17d0 [c00009cf365c7d70] c0000000008d1098 do_page_fault+0x3a8/0x800 [c00009cf365c7e30] c000000000008664 handle_page_fault+0x10/0x30 I think we are hitting this race issue when the migrate entry page is not locked. dump_page() for *old page: page:f00000035f36a5a0 count:1 mapcount:0 mapping:c00009cf3d351311 index:0x3ffffffe flags: 0x93ffff800080009(locked|uptodate|swapbacked) dump_page() for migrate entry page: page:f00000009f36a5a0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x13ffff800000000() Any suggestions on how to debug this issue? Thanks Haren -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/