On 07/02/2014 07:55 AM, Sasha Levin wrote: > Hi all, > > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following spew: > > [ 3569.869749] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC > [ 3569.869769] Dumping ftrace buffer: > [ 3569.869879] (ftrace buffer empty) > [ 3569.869894] Modules linked in: > [ 3569.869900] CPU: 7 PID: 10239 Comm: trinity-c86 Tainted: G W 3.16.0-rc3-next-20140701-sasha-00023-g4eb2544-dirty #759 > [ 3569.869906] task: ffff88039e873000 ti: ffff880393f8c000 task.ti: ffff880393f8c000 > [ 3569.869932] RIP: show_mountinfo (fs/proc_namespace.c:127) > [ 3569.869938] RSP: 0018:ffff880393f8fd08 EFLAGS: 00010282 > [ 3569.869943] RAX: ffff880200c6d208 RBX: 6b6b6b6b6b6b6b03 RCX: 0000000000000074 > [ 3569.869946] RDX: 0000000000000000 RSI: 6b6b6b6b6b6b6b03 RDI: ffff880200c6d208 > [ 3569.869953] RBP: ffff880393f8fd58 R08: 0000000000000001 R09: ffff88039e873d38 > [ 3569.869957] R10: 0000000000000001 R11: 0000000000000000 R12: ffff880200c6d208 > [ 3569.869962] R13: 6b6b6b6b6b6b6b6b R14: ffff880393f8ff50 R15: ffff880200c6d208 > [ 3569.869966] FS: 00007f6f20db9700(0000) GS:ffff8801ece00000(0000) knlGS:0000000000000000 > [ 3569.869969] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 3569.869974] CR2: 00007f6f20bee000 CR3: 00000003a0775000 CR4: 00000000000006a0 > [ 3569.869992] Stack: > [ 3569.870011] ffff880393f8ff50 ffff880200c6d208 ffff880393f8fd48 ffffffff984e10ea > [ 3569.870025] ffffffff9532c7fe ffff8802069a3b80 0000000000000065 6b6b6b6b6b6b6b6b > [ 3569.870036] ffff880393f8ff50 ffff880200c6d208 ffff880393f8fd68 ffffffff9532c756 > [ 3569.870038] Call Trace: > [ 3569.870051] ? down_read (kernel/locking/rwsem.c:45 (discriminator 2)) > [ 3569.870059] ? m_start (kernel/module.c:3634) > [ 3569.870069] m_show (kernel/module.c:3649) > [ 3569.870076] seq_read (fs/seq_file.c:235) > [ 3569.870081] ? single_open_size (fs/seq_file.c:166) > [ 3569.870092] do_loop_readv_writev (fs/read_write.c:708) > [ 3569.870098] ? single_open_size (fs/seq_file.c:166) > [ 3569.870098] do_readv_writev (fs/read_write.c:840) > [ 3569.870098] ? get_parent_ip (kernel/sched/core.c:2550) > [ 3569.870098] ? mutex_lock_nested (./arch/x86/include/asm/preempt.h:98 kernel/locking/mutex.c:570 kernel/locking/mutex.c:587) > [ 3569.870098] ? __fdget_pos (fs/file.c:714) > [ 3569.870098] ? __fdget_pos (fs/file.c:714) > [ 3569.870098] ? trace_hardirqs_on_caller (kernel/locking/lockdep.c:2557 kernel/locking/lockdep.c:2599) > [ 3569.870098] ? __fget_light (fs/file.c:685) > [ 3569.870098] vfs_readv (fs/read_write.c:866) > [ 3569.870098] SyS_readv (fs/read_write.c:892 fs/read_write.c:884) > [ 3569.870098] tracesys (arch/x86/kernel/entry_64.S:542) > [ 3569.870098] Code: 00 00 00 00 66 66 66 66 90 55 48 89 e5 48 83 ec 50 48 89 5d d8 48 89 f3 4c 89 65 e0 49 89 fc 4c 89 6d e8 4c 89 75 f0 4c 89 7d f8 <48> 8b 06 48 89 75 b0 4c 8b 76 08 8b 96 ec 00 00 00 48 89 45 b8 > All code > ======== > 0: 00 00 add %al,(%rax) > 2: 00 00 add %al,(%rax) > 4: 66 66 66 66 90 data32 data32 data32 xchg %ax,%ax > 9: 55 push %rbp > a: 48 89 e5 mov %rsp,%rbp > d: 48 83 ec 50 sub $0x50,%rsp > 11: 48 89 5d d8 mov %rbx,-0x28(%rbp) > 15: 48 89 f3 mov %rsi,%rbx > 18: 4c 89 65 e0 mov %r12,-0x20(%rbp) > 1c: 49 89 fc mov %rdi,%r12 > 1f: 4c 89 6d e8 mov %r13,-0x18(%rbp) > 23: 4c 89 75 f0 mov %r14,-0x10(%rbp) > 27: 4c 89 7d f8 mov %r15,-0x8(%rbp) > 2b:* 48 8b 06 mov (%rsi),%rax <-- trapping instruction > 2e: 48 89 75 b0 mov %rsi,-0x50(%rbp) > 32: 4c 8b 76 08 mov 0x8(%rsi),%r14 > 36: 8b 96 ec 00 00 00 mov 0xec(%rsi),%edx > 3c: 48 89 45 b8 mov %rax,-0x48(%rbp) > ... > > Code starting with the faulting instruction > =========================================== > 0: 48 8b 06 mov (%rsi),%rax > 3: 48 89 75 b0 mov %rsi,-0x50(%rbp) > 7: 4c 8b 76 08 mov 0x8(%rsi),%r14 > b: 8b 96 ec 00 00 00 mov 0xec(%rsi),%edx > 11: 48 89 45 b8 mov %rax,-0x48(%rbp) > ... > [ 3569.870098] RIP show_mountinfo (fs/proc_namespace.c:127) > [ 3569.870098] RSP <ffff880393f8fd08> > > > Thanks, > Sasha > This one seems related: [ 4292.460172] kernel tried to execute NX-protected page - exploit attempt? (uid: 84) [ 4292.462109] BUG: unable to handle kernel paging request at ffff8804650c3ec8 [ 4292.464167] IP: 0xffff8804650c3ec8 (??:?) [ 4292.465775] PGD 24b7d067 PUD 703f42067 PMD 703e19067 PTE 80000004650c3163 [ 4292.467882] Oops: 0011 [#1] PREEMPT SMP DEBUG_PAGEALLOC [ 4292.469606] Dumping ftrace buffer: [ 4292.470032] (ftrace buffer empty) [ 4292.470032] Modules linked in: [ 4292.470032] CPU: 9 PID: 16397 Comm: trinity-c103 Tainted: G W 3.16.0-rc3-next-20140702-sasha-00023-ga35ffce-dirty #760 [ 4292.470032] task: ffff8801b479b000 ti: ffff8804650c0000 task.ti: ffff8804650c0000 [ 4292.470032] RIP: 0xffff8804650c3ec8 (??:?) [ 4292.470032] RSP: 0000:ffff8804650c3e60 EFLAGS: 00010293 [ 4292.470032] RAX: ffff8803d5e586a0 RBX: ffff88007bf85b00 RCX: ffff8800a5ab69a8 [ 4292.470032] RDX: 0000000000000000 RSI: ffffffffa31352f8 RDI: ffff8803d5e5b6a8 [ 4292.470032] RBP: ffff8804650c3e58 R08: ffff8803d5e5b6a8 R09: 0000000000000009 [ 4292.470032] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 [ 4292.490142] R13: ffff8803d5e5b6a8 R14: ffff8804650c3f50 R15: ffff88008082e900 [ 4292.490142] FS: 00007ff380e2e700(0000) GS:ffff88025ce00000(0000) knlGS:0000000000000000 [ 4292.490142] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 4292.490142] CR2: ffff8804650c3ec8 CR3: 000000017f20e000 CR4: 00000000000006a0 [ 4292.490142] Stack: [ 4292.490142] ffffffff9d332972 0000000000000009 0000000081000000 ffff88008082e940 [ 4292.490142] 0000000000000e5f 0000000000000000 0000000000000001 ffff8804650c3ec8 [ 4292.490142] ffff8803d69b1ff0 ffff88007bf85b00 0000000081000000 ffff8804650c3f50 [ 4292.490142] Call Trace: [ 4292.490142] seq_read (fs/seq_file.c:265) [ 4292.490142] ? proc_reg_read (fs/proc/inode.c:211) [ 4292.508936] ? vfs_read (fs/read_write.c:430) [ 4292.508936] ? SyS_read (fs/read_write.c:568 fs/read_write.c:560) [ 4292.508936] ? ia32_do_call (arch/x86/ia32/ia32entry.S:430) [ 4292.508936] Code: 88 ff ff f0 1f 9b d6 03 88 ff ff 00 5b f8 7b 00 88 ff ff 00 00 00 81 00 00 00 00 50 3f 0c 65 04 88 ff ff 03 00 00 00 00 00 00 00 <f8> 3e 0c 65 04 88 ff ff 42 ae 37 9d ff ff ff ff 08 3f 0c 65 04 All code ======== 0: 88 ff mov %bh,%bh 2: ff f0 push %rax 4: 1f (bad) 5: 9b fwait 6: d6 (bad) 7: 03 88 ff ff 00 5b add 0x5b00ffff(%rax),%ecx d: f8 clc e: 7b 00 jnp 0x10 10: 88 ff mov %bh,%bh 12: ff 00 incl (%rax) 14: 00 00 add %al,(%rax) 16: 81 00 00 00 00 50 addl $0x50000000,(%rax) 1c: 3f (bad) 1d: 0c 65 or $0x65,%al 1f: 04 88 add $0x88,%al 21: ff (bad) 22: ff 03 incl (%rbx) 24: 00 00 add %al,(%rax) 26: 00 00 add %al,(%rax) 28: 00 00 add %al,(%rax) 2a:* 00 f8 add %bh,%al <-- trapping instruction 2c: 3e ds 2d: 0c 65 or $0x65,%al 2f: 04 88 add $0x88,%al 31: ff (bad) 32: ff 42 ae incl -0x52(%rdx) 35: 37 (bad) 36: 9d popfq 37: ff (bad) 38: ff (bad) 39: ff (bad) 3a: ff 08 decl (%rax) 3c: 3f (bad) 3d: 0c 65 or $0x65,%al 3f: 04 00 add $0x0,%al Code starting with the faulting instruction =========================================== 0: f8 clc 1: 3e ds 2: 0c 65 or $0x65,%al 4: 04 88 add $0x88,%al 6: ff (bad) 7: ff 42 ae incl -0x52(%rdx) a: 37 (bad) b: 9d popfq c: ff (bad) d: ff (bad) e: ff (bad) f: ff 08 decl (%rax) 11: 3f (bad) 12: 0c 65 or $0x65,%al 14: 04 00 add $0x0,%al [ 4292.508936] RIP 0xffff8804650c3ec8 (??:?) [ 4292.508936] RSP <ffff8804650c3e60> [ 4292.508936] CR2: ffff8804650c3ec8 Thanks, Sasha -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
