I just noticed that recent mmotm and linux-next kernels will not boot if you attempt to preallocate 1G huge pages at boot time (on x86). To preallocate, simply add "hugepagesz=1G hugepages=1" to kernel command line. I have not yet started to debug. However, based on the "BUG_ON(page_mapcount(page));" I am guessing it is related to recent mapcount/refcount changes. [ 0.465644] ------------[ cut here ]------------ [ 0.467640] kernel BUG at mm/hugetlb.c:1218! [ 0.468745] invalid opcode: 0000 [#1] SMP [ 0.469989] Modules linked in: [ 0.470867] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.4.0 #1 [ 0.471724] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.8.1-20150318_183358- 04/01/2014 [ 0.473162] task: ffff880236290000 ti: ffff880236298000 task.ti: ffff880236298000 [ 0.474417] RIP: 0010:[<ffffffff811e3422>] [<ffffffff811e3422>] free_huge_page+0x2a2/0x2b0 [ 0.475791] RSP: 0000:ffff88023629bdc8 EFLAGS: 00010202 [ 0.476583] RAX: 0000000000000001 RBX: ffffffff81f97d60 RCX: ffffea000700001f [ 0.477555] RDX: 0000000000000000 RSI: ffffffff81f993d0 RDI: ffffea0007000000 [ 0.478697] RBP: ffff88023629bdf0 R08: 00000000001c0000 R09: ffffea0007000001 [ 0.479636] R10: 0000000000040000 R11: ffffffff81f993be R12: ffffea0007000000 [ 0.480572] R13: 0200000000004000 R14: 0000000000000000 R15: ffffea0007000000 [ 0.481519] FS: 0000000000000000(0000) GS:ffff88023fc00000(0000) knlGS:0000000000000000 [ 0.482991] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 0.484018] CR2: 00000000ffffffff CR3: 0000000001c09000 CR4: 00000000001406f0 [ 0.485210] Stack: [ 0.485782] ffffea0007000000 ffffffff81f97d60 0000000000000001 ffffea0000000000 [ 0.487462] ffffea0007000000 ffff88023629be08 ffffffff811a0a30 ffffea0007000000 [ 0.489175] ffff88023629be20 ffffffff811a103a ffff8801c0000000 ffff88023629be88 [ 0.490873] Call Trace: [ 0.491507] [<ffffffff811a0a30>] __put_compound_page+0x30/0x50 [ 0.492549] [<ffffffff811a103a>] __put_page+0x1a/0x40 [ 0.493498] [<ffffffff81d80e76>] hugetlb_init+0x5c0/0x5d4 [ 0.494500] [<ffffffff81002113>] ? do_one_initcall+0xa3/0x200 [ 0.495528] [<ffffffff81d808b6>] ? hugetlb_add_hstate+0x180/0x180 [ 0.497509] [<ffffffff81d808b6>] ? hugetlb_add_hstate+0x180/0x180 [ 0.498366] [<ffffffff81002123>] do_one_initcall+0xb3/0x200 [ 0.499173] [<ffffffff810b52f5>] ? parse_args+0x295/0x4b0 [ 0.499965] [<ffffffff81d52192>] kernel_init_freeable+0x16d/0x207 [ 0.500815] [<ffffffff81750640>] ? rest_init+0x80/0x80 [ 0.501586] [<ffffffff8175064e>] kernel_init+0xe/0xe0 [ 0.509314] [<ffffffff8175c7cf>] ret_from_fork+0x3f/0x70 [ 0.510117] [<ffffffff81750640>] ? rest_init+0x80/0x80 [ 0.510886] Code: c0 01 e9 7e fe ff ff 48 c7 c6 28 8b a5 81 4c 89 e7 e8 93 b8 fd ff 0f 0b 0f 0b 48 c7 c6 e0 75 a5 81 4c 89 e7 e8 80 b8 fd ff 0f 0b <0f> 0b 66 66 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 [ 0.516745] RIP [<ffffffff811e3422>] free_huge_page+0x2a2/0x2b0 [ 0.517650] RSP <ffff88023629bdc8> [ 0.518303] ---[ end trace 6f9049db529aa0d6 ]--- [ 0.519043] Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 0.519043] [ 0.520782] ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b [ 0.520782] -- Mike Kravetz -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>