Hi all, While fuzzing with trinity inside a KVM tools guest running the latest -next kernel, I've stumbled on the following spew: [ 2957.087977] BUG: unable to handle kernel paging request at ffffea0003480008 [ 2957.088008] IP: unmap_page_range (mm/memory.c:1132 mm/memory.c:1256 mm/memory.c:1277 mm/memory.c:1301) [ 2957.088024] PGD 7fffc6067 PUD 7fffc5067 PMD 0 [ 2957.088041] Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 2957.088087] Dumping ftrace buffer: [ 2957.088266] (ftrace buffer empty) [ 2957.088279] Modules linked in: [ 2957.088293] CPU: 2 PID: 15417 Comm: trinity-c200 Not tainted 3.16.0-rc7-next-20140801-sasha-00047-gd6ce559 #990 [ 2957.088301] task: ffff8807a8c50000 ti: ffff880739fb4000 task.ti: ffff880739fb4000 [ 2957.088320] RIP: unmap_page_range (mm/memory.c:1132 mm/memory.c:1256 mm/memory.c:1277 mm/memory.c:1301) [ 2957.088328] RSP: 0018:ffff880739fb7c58 EFLAGS: 00010246 [ 2957.088336] RAX: 0000000000000000 RBX: ffff880eb2bdbed8 RCX: dfff971b42800000 [ 2957.088343] RDX: 1ffff100e73f6fc4 RSI: 00007f00e85db000 RDI: ffffea0003480008 [ 2957.088350] RBP: ffff880739fb7d58 R08: 0000000000000001 R09: 0000000000b6e000 [ 2957.088357] R10: 0000000000000000 R11: 0000000000000001 R12: ffffea0003480000 [ 2957.088365] R13: 00000000d2000700 R14: 00007f00e85dc000 R15: 00007f00e85db000 [ 2957.088374] FS: 00007f00e85d8700(0000) GS:ffff88177fa00000(0000) knlGS:0000000000000000 [ 2957.088381] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 2957.088387] CR2: ffffea0003480008 CR3: 00000007a802a000 CR4: 00000000000006a0 [ 2957.088406] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 2957.088413] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600 [ 2957.088416] Stack: [ 2957.088432] ffff88171726d570 0000000000000010 0000000000000008 00000000d2000730 [ 2957.088450] 0000000019d00250 00007f00e85dc000 ffff880f9d311900 ffff880739fb7e20 [ 2957.088466] ffff8807a8c507a0 ffff8807a8c50000 ffff8807a75fe000 ffff8807ceaa7a10 [ 2957.088469] Call Trace: [ 2957.088490] unmap_single_vma (mm/memory.c:1348) [ 2957.088505] unmap_vmas (mm/memory.c:1375 (discriminator 3)) [ 2957.088520] unmap_region (mm/mmap.c:2386 (discriminator 4)) [ 2957.088542] ? vma_rb_erase (mm/mmap.c:454 include/linux/rbtree_augmented.h:219 include/linux/rbtree_augmented.h:227 mm/mmap.c:493) [ 2957.088559] ? vmacache_update (mm/vmacache.c:61) [ 2957.088572] do_munmap (mm/mmap.c:2581) [ 2957.088583] vm_munmap (mm/mmap.c:2596) [ 2957.088595] SyS_munmap (mm/mmap.c:2601) [ 2957.088616] tracesys (arch/x86/kernel/entry_64.S:541) [ 2957.088770] Code: ff ff e8 f9 5f 07 00 48 8b 45 90 80 48 18 01 4d 85 e4 0f 84 8b fe ff ff 45 84 ed 0f 85 fc 03 00 00 49 8d 7c 24 08 e8 b5 67 07 00 <41> f6 44 24 08 01 0f 84 29 02 00 00 83 6d c8 01 4c 89 e7 e8 bd All code ======== 0: ff (bad) 1: ff e8 ljmpq *<internal disassembler error> 3: f9 stc 4: 5f pop %rdi 5: 07 (bad) 6: 00 48 8b add %cl,-0x75(%rax) 9: 45 90 rex.RB xchg %eax,%r8d b: 80 48 18 01 orb $0x1,0x18(%rax) f: 4d 85 e4 test %r12,%r12 12: 0f 84 8b fe ff ff je 0xfffffffffffffea3 18: 45 84 ed test %r13b,%r13b 1b: 0f 85 fc 03 00 00 jne 0x41d 21: 49 8d 7c 24 08 lea 0x8(%r12),%rdi 26: e8 b5 67 07 00 callq 0x767e0 2b:* 41 f6 44 24 08 01 testb $0x1,0x8(%r12) <-- trapping instruction 31: 0f 84 29 02 00 00 je 0x260 37: 83 6d c8 01 subl $0x1,-0x38(%rbp) 3b: 4c 89 e7 mov %r12,%rdi 3e: e8 .byte 0xe8 3f: bd .byte 0xbd ... Code starting with the faulting instruction =========================================== 0: 41 f6 44 24 08 01 testb $0x1,0x8(%r12) 6: 0f 84 29 02 00 00 je 0x235 c: 83 6d c8 01 subl $0x1,-0x38(%rbp) 10: 4c 89 e7 mov %r12,%rdi 13: e8 .byte 0xe8 14: bd .byte 0xbd ... [ 2957.088784] RIP unmap_page_range (mm/memory.c:1132 mm/memory.c:1256 mm/memory.c:1277 mm/memory.c:1301) [ 2957.088789] RSP <ffff880739fb7c58> [ 2957.088794] CR2: ffffea0003480008 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>