Hi Rik, While fuzzing with trinity inside a KVM tools guest running latest -next kernel I've hit the following spew. This seems to be introduced by your patch "mm,numa: reorganize change_pmd_range()". [ 886.745765] kernel BUG at mm/mprotect.c:149! [ 886.746831] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 886.748511] Dumping ftrace buffer: [ 886.749998] (ftrace buffer empty) [ 886.750110] Modules linked in: [ 886.751396] CPU: 20 PID: 26219 Comm: trinity-c216 Tainted: G W 3.14.0-rc5-next-20140305-sasha-00011-ge06f5f3-dirty #105 [ 886.751396] task: ffff8800b6c80000 ti: ffff880228436000 task.ti: ffff880228436000 [ 886.751396] RIP: 0010:[<ffffffff812aab33>] [<ffffffff812aab33>] change_protection_range+0x3b3/0x500 [ 886.751396] RSP: 0000:ffff880228437da8 EFLAGS: 00010282 [ 886.751396] RAX: 8000000527c008e5 RBX: 00007f647916e000 RCX: 0000000000000000 [ 886.751396] RDX: ffff8802ef488e40 RSI: 00007f6479000000 RDI: 8000000527c008e5 [ 886.751396] RBP: ffff880228437e78 R08: 0000000000000000 R09: 0000000000000000 [ 886.751396] R10: 0000000000000001 R11: 0000000000000000 R12: ffff8802ef488e40 [ 886.751396] R13: 00007f6479000000 R14: 00007f647916e000 R15: 00007f646e34e000 [ 886.751396] FS: 00007f64b28d4700(0000) GS:ffff88052ba00000(0000) knlGS:0000000000000000 [ 886.751396] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 886.751396] CR2: 00007f64aed83af8 CR3: 0000000206e52000 CR4: 00000000000006a0 [ 886.751396] Stack: [ 886.751396] ffff880200000001 ffffffff8447f152 ffff880228437dd8 ffff880228af3000 [ 886.769142] 00007f646e34e000 00007f647916dfff 0000000000000000 00007f647916e000 [ 886.769142] ffff880206e527f0 00007f647916dfff 0000000000000000 0000000000000000 [ 886.769142] Call Trace: [ 886.769142] [<ffffffff8447f152>] ? preempt_count_sub+0xe2/0x120 [ 886.769142] [<ffffffff812aaca5>] change_protection+0x25/0x30 [ 886.769142] [<ffffffff812c3eeb>] change_prot_numa+0x1b/0x30 [ 886.769142] [<ffffffff8118df49>] task_numa_work+0x279/0x360 [ 886.769142] [<ffffffff8116c57e>] task_work_run+0xae/0xf0 [ 886.769142] [<ffffffff8106ffbe>] do_notify_resume+0x8e/0xe0 [ 886.769142] [<ffffffff8447a93b>] retint_signal+0x4d/0x92 [ 886.769142] Code: 49 8b 3c 24 48 83 3d fc 2e ba 04 00 75 12 0f 0b 0f 1f 84 00 00 00 00 00 eb fe 66 0f 1f 44 00 00 48 89 f8 66 66 66 90 84 c0 79 0d <0f> 0b 0f 1f 00 eb fe 66 0f 1f 44 00 00 8b 4d 9c 44 8b 4d 98 89 [ 886.769142] RIP [<ffffffff812aab33>] change_protection_range+0x3b3/0x500 [ 886.769142] RSP <ffff880228437da8> Thanks, Sasha -- 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>