ptrace: gpf in syscall_trace_enter

Sasha Levin
2014-05-07T00:36:58Z

Hi all,

While fuzzing with trinity inside a KVM tools guest running the latest -next
kernel I've stumbled on the following spew:

[ 3029.100936] general protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 3029.102198] Dumping ftrace buffer:
[ 3029.102928] (ftrace buffer empty)
[ 3029.103644] Modules linked in:
[ 3029.104732] CPU: 16 PID: 4959 Comm: sleep Tainted: G B 3.15.0-rc4-next-20140506-sasha-00021-gc164334-dirty #447
[ 3029.108662] task: ffff8805472f8000 ti: ffff880547e3e000 task.ti: ffff880547e3e000
[ 3029.109900] RIP: syscall_trace_enter (include/trace/events/syscalls.h:16 arch/x86/kernel/ptrace.c:1488)
[ 3029.110064] RSP: 0018:ffff880547e3ff28 EFLAGS: 00010286
[ 3029.110064] RAX: 0000000000000000 RBX: ffff880547e3ff58 RCX: 0000000000000001
[ 3029.110064] RDX: 000000000000000c RSI: ffff880547e3ff58 RDI: 6b6b6b6b6b6b6b6b
[ 3029.110064] RBP: ffff880547e3ff48 R08: 0000000000000000 R09: 0000000000000001
[ 3029.110064] R10: 0000000000000000 R11: 0000000000000000 R12: 000000000000000c
[ 3029.110064] R13: 0000000000000000 R14: ffff880039583d50 R15: 0000000000001000
[ 3029.110064] FS: 0000000000000000(0000) GS:ffff8803d6e00000(0000) knlGS:0000000000000000
[ 3029.110064] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[ 3029.110064] CR2: 00007fe08b205130 CR3: 000000061d271000 CR4: 00000000000006a0
[ 3029.110064] DR0: 00000000006df000 DR1: 0000000000000000 DR2: 0000000000000000
[ 3029.110064] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
[ 3029.110064] Stack:
[ 3029.110064] 0000000000400040 0000000000000009 00007fffe95ab4b9 0000000000000000
[ 3029.110064] 00007fe08afe64e0 ffffffffaa585625 0000000000001000 0000000000000000
[ 3029.110064] 00007fffe95ab4b9 0000000000000009 00007fe08afe64e0 0000000000400040
[ 3029.110064] Call Trace:
[ 3029.110064] tracesys (arch/x86/kernel/entry_64.S:736)
[ 3029.110064] Code: c6 05 e0 9f f0 05 01 e8 3d 30 14 00 4d 85 f6 75 10 65 ff 0c 25 a0 da 00 00 0f 84 ca 00 00 00 eb 19 49 8b 7e 08 4c 89 e2 48 89 de <41> ff 16 49 83 c6 10 49 83 3e 00 75 e9 eb d7 4c 8b 63 78 0f 1f
[ 3029.110064] RIP syscall_trace_enter (include/trace/events/syscalls.h:16 arch/x86/kernel/ptrace.c:1488)
[ 3029.110064] RSP <ffff880547e3ff28>

Thanks,
Sasha