From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
To: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
"David S. Miller" <davem@davemloft.net>,
Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: [BUG kretprobes] kretprobe triggers General Protection Faults
Date: Tue, 25 Feb 2014 19:46:01 +0000 (UTC) [thread overview]
Message-ID: <1332921457.30140.1393357561516.JavaMail.zimbra@efficios.com> (raw)
In-Reply-To: <1164803689.30103.1393357052243.JavaMail.zimbra@efficios.com>
Hi,
I had a bug report[1] from a user trying to add a kretprobe on the system
call entry code path:
arch/x86/kernel/entry_64.S:
ffffffff813dffe2 <system_call_fastpath+0x16>:
cmpl $__NR_syscall_max,%eax
#endif
ja badsys
movq %r10,%rcx
call *sys_call_table(,%rax,8) # XXX: rip relative
movq %rax,RAX-ARGOFFSET(%rsp) <--- return address pointing here
And all hell breaks loose (various types of faults, machine reboots,
applications exit randomly, etc.). I understand that this code path
is not marked as unsafe against kprobes, and I tested that a kprobes
indeed works fine there. However, kretprobes probably presumes a function
stack layout that is just not valid for the syscall entry routine.
Any thoughts on how kretprobes should handle this ?
Thanks,
Mathieu
[1] http://bugs.lttng.org/issues/687
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
next parent reply other threads:[~2014-02-25 19:46 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1164803689.30103.1393357052243.JavaMail.zimbra@efficios.com>
2014-02-25 19:46 ` Mathieu Desnoyers [this message]
2014-02-26 2:48 ` [BUG kretprobes] kretprobe triggers General Protection Faults Masami Hiramatsu
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