On Wed, 2013-03-27 at 17:44 +0800, zhangwei(Jovi) wrote:
> From: "zhangwei(Jovi)" <jovi.zhangwei@xxxxxxxxxx>
>
> Using perf command: perf stat -e ftrace:function ls
>
> this will cause kernel warning and oops.
>
> [ 797.828904] ------------[ cut here ]------------
> [ 797.828946] WARNING: at include/linux/ftrace.h:209 ftrace_ops_control_func+0xb1/0xc0()
> [ 797.829065] Pid: 6086, comm: perf Not tainted 3.8.0-rc4+ #88
> [ 797.829066] Call Trace:
> [ 797.829078] [<c0447a42>] warn_slowpath_common+0x72/0xa0
> [ 797.829080] [<c04bd6d1>] ? ftrace_ops_control_func+0xb1/0xc0
> [ 797.829082] [<c04bd6d1>] ? ftrace_ops_control_func+0xb1/0xc0
> [ 797.829083] [<c04b7453>] ? synchronize_sched+0x3/0x50
> [ 797.829085] [<c04be50f>] ? __unregister_ftrace_function+0x8f/0x170
> [ 797.829087] [<c0447a92>] warn_slowpath_null+0x22/0x30
> [ 797.829089] [<c04bd6d1>] ftrace_ops_control_func+0xb1/0xc0
> [ 797.829099] [<c08eba6b>] ftrace_call+0x5/0xb
> [ 797.829100] [<c04b7458>] ? synchronize_sched+0x8/0x50
> [ 797.829102] [<c04be50f>] __unregister_ftrace_function+0x8f/0x170
> [ 797.829104] [<c04c00cf>] unregister_ftrace_function+0x1f/0x50
> [ 797.829109] [<c04d31bd>] perf_ftrace_event_register+0x9d/0x140
> [ 797.829111] [<c04d304b>] perf_trace_destroy+0x2b/0x50
> [ 797.829117] [<c04db3c8>] tp_perf_event_destroy+0x8/0x10
> [ 797.829119] [<c04dd672>] free_event+0x42/0x110
> [ 797.829121] [<c04de446>] perf_event_release_kernel+0x56/0x90
> [ 797.829122] [<c04de4fc>] put_event+0x7c/0xa0
> [ 797.829124] [<c04de5cb>] perf_release+0xb/0x10
> [ 797.829128] [<c0532ae6>] __fput+0xc6/0x1f0
> [ 797.829130] [<c0532c1d>] ____fput+0xd/0x10
> [ 797.829134] [<c04645b1>] task_work_run+0x81/0xa0
> [ 797.829142] [<c0412819>] do_notify_resume+0x59/0x90
> [ 797.829150] [<c08e4745>] work_notifysig+0x30/0x37
> [ 797.829152] ---[ end trace 4dbd63f12b55163f ]---
>
> This bug was introduced by below commit(in 3.8-rc4):
> commit 0a016409e42f273415f8225ddf2c58eb2df88034
> Author: Steven Rostedt <srostedt@xxxxxxxxxx>
> Date: Fri Nov 2 17:03:03 2012 -0400
>
> ftrace: Optimize the function tracer list loop
>
> When variable op is ftrace_list_end, it cannot pass control ops checking,
> so that loop optimize is not suit for ftrace_control_list, change it back.
>
Thanks for finding the bug, but this isn't the fix.
> Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> kernel/trace/ftrace.c | 7 +++++--
> 1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
> index 2577082..2899974 100644
> --- a/kernel/trace/ftrace.c
> +++ b/kernel/trace/ftrace.c
> @@ -4185,11 +4185,14 @@ ftrace_ops_control_func(unsigned long ip, unsigned long parent_ip,
> */
> preempt_disable_notrace();
> trace_recursion_set(TRACE_CONTROL_BIT);
> - do_for_each_ftrace_op(op, ftrace_control_list) {
I'd much rather keep the do_for_each_op() as it keeps everything
consistent, and I don't have to worry about this if I change things in
the future.
I'll fix this so that it wont process stub functions.
Thanks!
-- Steve
> + op = rcu_dereference_raw(ftrace_control_list);
> + while (op != &ftrace_list_end) {
> if (!ftrace_function_local_disabled(op) &&
> ftrace_ops_test(op, ip))
> op->func(ip, parent_ip, op, regs);
> - } while_for_each_ftrace_op(op);
> +
> + op = rcu_dereference_raw(op->next);
> + }
> trace_recursion_clear(TRACE_CONTROL_BIT);
> preempt_enable_notrace();
> }
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html