Hi, I've got the following error report while fuzzing the kernel with syzkaller. On commit 9705596d08ac87c18aee32cc97f2783b7d14624e (4.12-rc6+). A reproducer and .config are attached. ------------[ cut here ]------------ WARNING: CPU: 1 PID: 4313 at mm/page_alloc.c:3700 __alloc_pages_slowpath+0x18fd/0x2360 Modules linked in: CPU: 1 PID: 4313 Comm: a.out Not tainted 4.12.0-rc6+ #11 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 task: ffff88006a8c1600 task.stack: ffff8800640b8000 RIP: 0010:should_compact_retry mm/page_alloc.c:3385 RIP: 0010:__alloc_pages_slowpath+0x18fd/0x2360 mm/page_alloc.c:3866 RSP: 0018:ffff8800640bec48 EFLAGS: 00010246 RAX: 0000000100010fde RBX: 00000000014000c0 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000014 RDI: 000000000140c0c0 RBP: ffff8800640bf180 R08: 0000000000000000 R09: fffffffffff00f88 R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff1000c817e38 R13: ffff8800640bf220 R14: ffff8800640bf340 R15: ffff8800640bf2e0 FS: 00007facb1334700(0000) GS:ffff88006cb00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020781000 CR3: 0000000065757000 CR4: 00000000000006e0 Call Trace: __alloc_pages_nodemask+0x914/0xc80 mm/page_alloc.c:4039 alloc_pages_current+0x1cc/0x6b0 mm/mempolicy.c:2065 alloc_pages ./include/linux/gfp.h:478 kmalloc_order+0x24/0x70 mm/slab_common.c:1114 kmalloc_order_trace+0x24/0x160 mm/slab_common.c:1125 kmalloc_large ./include/linux/slab.h:424 __kmalloc+0x215/0x2d0 mm/slub.c:3734 kmalloc_array ./include/linux/slab.h:611 kcalloc ./include/linux/slab.h:622 ipip6_tunnel_get_prl net/ipv6/sit.c:308 ipip6_tunnel_ioctl+0xed1/0x2070 net/ipv6/sit.c:1263 dev_ifsioc+0x544/0x9f0 net/core/dev_ioctl.c:338 dev_ioctl+0xc41/0x1160 net/core/dev_ioctl.c:555 sock_ioctl+0x16e/0x440 net/socket.c:944 vfs_ioctl fs/ioctl.c:45 do_vfs_ioctl+0x1c4/0x1660 fs/ioctl.c:685 SYSC_ioctl fs/ioctl.c:700 SyS_ioctl+0x94/0xc0 fs/ioctl.c:691 entry_SYSCALL_64_fastpath+0x1f/0xbe arch/x86/entry/entry_64.S:203 RIP: 0033:0x7facb0a46b79 RSP: 002b:00007ffeb5763068 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007ffeb5763170 RCX: 00007facb0a46b79 RDX: 0000000020781000 RSI: 00000000000089f4 RDI: 0000000000000004 RBP: 00000000004004e0 R08: 0003000000000019 R09: 0000000000000000 R10: 00e315ffffff0300 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffeb5763170 R14: 0000000000000000 R15: 0000000000000000 Code: ff ff 39 d8 0f 8f b4 01 00 00 8b 85 d8 fa ff ff c7 85 98 fb ff ff 01 00 00 00 41 bd 01 00 00 00 89 85 a0 fb ff ff e9 2d fc ff ff <0f> ff e9 ca e8 ff ff 0f ff 89 d8 c7 85 ec fa ff ff 00 00 00 00 ---[ end trace edcb5387b3d4d646 ]---