When configure kprobe events of ftrace with "stacktrace" option enabled
in arm, there is no stacktrace was recorded after the kprobe event was
triggered. The root cause is no save_stack_trace_regs() function implemented.
Implement the save_stack_trace_regs() function in arm, then ftrace will
call this architecture-related function to record the stacktrace into
ring buffer.
After this fix, stacktrace can be recorded, for example:
# mount -t debugfs nodev /sys/kernel/debug
# echo "p:netrx net_rx_action" >> /sys/kernel/debug/tracing/kprobe_events
# echo 1 > /sys/kernel/debug/tracing/events/kprobes/netrx/enable
# echo 1 > /sys/kernel/debug/tracing/options/stacktrace
# echo 1 > /sys/kernel/debug/tracing/tracing_on
# ping 127.0.0.1 -c 1
# echo 0 > /sys/kernel/debug/tracing/tracing_on
# cat /sys/kernel/debug/tracing/trace
# tracer: nop
#
# entries-in-buffer/entries-written: 12/12 #P:1
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
<------ missing some entries ---------------->
ping-1200 [000] dNs1 667.603250: netrx: (net_rx_action+0x0/0x1f8)
ping-1200 [000] dNs1 667.604738: <stack trace>
=> net_rx_action
=> do_softirq
=> local_bh_enable
=> ip_finish_output
=> ip_output
=> ip_local_out
=> ip_send_skb
=> ip_push_pending_frames
=> raw_sendmsg
=> inet_sendmsg
=> sock_sendmsg
=> SyS_sendto
=> ret_fast_syscall
Signed-off-by: Lin Yongting <[email protected]>
---
arch/arm/kernel/stacktrace.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index af4e8c8..c558db6 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -123,6 +123,25 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
trace->entries[trace->nr_entries++] = ULONG_MAX;
}
+void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
+{
+ struct stack_trace_data data;
+ struct stackframe frame;
+
+ data.trace = trace;
+ data.skip = trace->skip;
+ data.no_sched_functions = 0;
+
+ frame.fp = regs->ARM_fp;
+ frame.sp = regs->ARM_sp;
+ frame.lr = regs->ARM_lr;
+ frame.pc = regs->ARM_pc;
+
+ walk_stackframe(&frame, save_trace, &data);
+ if (trace->nr_entries < trace->max_entries)
+ trace->entries[trace->nr_entries++] = ULONG_MAX;
+}
+
void save_stack_trace(struct stack_trace *trace)
{
save_stack_trace_tsk(current, trace);
--
1.7.9.5
On Wed, 23 Apr 2014 20:52:21 +0800
Lin Yongting <[email protected]> wrote:
> When configure kprobe events of ftrace with "stacktrace" option enabled
> in arm, there is no stacktrace was recorded after the kprobe event was
> triggered. The root cause is no save_stack_trace_regs() function implemented.
>
> Implement the save_stack_trace_regs() function in arm, then ftrace will
> call this architecture-related function to record the stacktrace into
> ring buffer.
>
> After this fix, stacktrace can be recorded, for example:
>
> # mount -t debugfs nodev /sys/kernel/debug
> # echo "p:netrx net_rx_action" >> /sys/kernel/debug/tracing/kprobe_events
> # echo 1 > /sys/kernel/debug/tracing/events/kprobes/netrx/enable
> # echo 1 > /sys/kernel/debug/tracing/options/stacktrace
> # echo 1 > /sys/kernel/debug/tracing/tracing_on
> # ping 127.0.0.1 -c 1
> # echo 0 > /sys/kernel/debug/tracing/tracing_on
>
> # cat /sys/kernel/debug/tracing/trace
> # tracer: nop
> #
> # entries-in-buffer/entries-written: 12/12 #P:1
> #
> # _-----=> irqs-off
> # / _----=> need-resched
> # | / _---=> hardirq/softirq
> # || / _--=> preempt-depth
> # ||| / delay
> # TASK-PID CPU# |||| TIMESTAMP FUNCTION
> # | | | |||| | |
> <------ missing some entries ---------------->
> ping-1200 [000] dNs1 667.603250: netrx: (net_rx_action+0x0/0x1f8)
> ping-1200 [000] dNs1 667.604738: <stack trace>
> => net_rx_action
> => do_softirq
> => local_bh_enable
> => ip_finish_output
> => ip_output
> => ip_local_out
> => ip_send_skb
> => ip_push_pending_frames
> => raw_sendmsg
> => inet_sendmsg
> => sock_sendmsg
> => SyS_sendto
> => ret_fast_syscall
>
> Signed-off-by: Lin Yongting <[email protected]>
> ---
As this affects ftrace for ARM...
Acked-by: Steven Rostedt <[email protected]>
-- Steve
> arch/arm/kernel/stacktrace.c | 19 +++++++++++++++++++
> 1 file changed, 19 insertions(+)
>
> diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
> index af4e8c8..c558db6 100644
> --- a/arch/arm/kernel/stacktrace.c
> +++ b/arch/arm/kernel/stacktrace.c
> @@ -123,6 +123,25 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
> trace->entries[trace->nr_entries++] = ULONG_MAX;
> }
>
> +void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
> +{
> + struct stack_trace_data data;
> + struct stackframe frame;
> +
> + data.trace = trace;
> + data.skip = trace->skip;
> + data.no_sched_functions = 0;
> +
> + frame.fp = regs->ARM_fp;
> + frame.sp = regs->ARM_sp;
> + frame.lr = regs->ARM_lr;
> + frame.pc = regs->ARM_pc;
> +
> + walk_stackframe(&frame, save_trace, &data);
> + if (trace->nr_entries < trace->max_entries)
> + trace->entries[trace->nr_entries++] = ULONG_MAX;
> +}
> +
> void save_stack_trace(struct stack_trace *trace)
> {
> save_stack_trace_tsk(current, trace);
2014-04-23 21:03 GMT+08:00 Steven Rostedt <[email protected]>:
> On Wed, 23 Apr 2014 20:52:21 +0800
> Lin Yongting <[email protected]> wrote:
>
>> When configure kprobe events of ftrace with "stacktrace" option enabled
>> in arm, there is no stacktrace was recorded after the kprobe event was
>> triggered. The root cause is no save_stack_trace_regs() function implemented.
>>
>> Implement the save_stack_trace_regs() function in arm, then ftrace will
>> call this architecture-related function to record the stacktrace into
>> ring buffer.
>>
>> After this fix, stacktrace can be recorded, for example:
>>
>> # mount -t debugfs nodev /sys/kernel/debug
>> # echo "p:netrx net_rx_action" >> /sys/kernel/debug/tracing/kprobe_events
>> # echo 1 > /sys/kernel/debug/tracing/events/kprobes/netrx/enable
>> # echo 1 > /sys/kernel/debug/tracing/options/stacktrace
>> # echo 1 > /sys/kernel/debug/tracing/tracing_on
>> # ping 127.0.0.1 -c 1
>> # echo 0 > /sys/kernel/debug/tracing/tracing_on
>>
>> # cat /sys/kernel/debug/tracing/trace
>> # tracer: nop
>> #
>> # entries-in-buffer/entries-written: 12/12 #P:1
>> #
>> # _-----=> irqs-off
>> # / _----=> need-resched
>> # | / _---=> hardirq/softirq
>> # || / _--=> preempt-depth
>> # ||| / delay
>> # TASK-PID CPU# |||| TIMESTAMP FUNCTION
>> # | | | |||| | |
>> <------ missing some entries ---------------->
>> ping-1200 [000] dNs1 667.603250: netrx: (net_rx_action+0x0/0x1f8)
>> ping-1200 [000] dNs1 667.604738: <stack trace>
>> => net_rx_action
>> => do_softirq
>> => local_bh_enable
>> => ip_finish_output
>> => ip_output
>> => ip_local_out
>> => ip_send_skb
>> => ip_push_pending_frames
>> => raw_sendmsg
>> => inet_sendmsg
>> => sock_sendmsg
>> => SyS_sendto
>> => ret_fast_syscall
>>
>> Signed-off-by: Lin Yongting <[email protected]>
>> ---
>
> As this affects ftrace for ARM...
>
> Acked-by: Steven Rostedt <[email protected]>
>
> -- Steve
>
Hi Russell
How about my Patch? any advice is appreciate。
Best Regards!
-- Yongting.
>> arch/arm/kernel/stacktrace.c | 19 +++++++++++++++++++
>> 1 file changed, 19 insertions(+)
>>
>> diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
>> index af4e8c8..c558db6 100644
>> --- a/arch/arm/kernel/stacktrace.c
>> +++ b/arch/arm/kernel/stacktrace.c
>> @@ -123,6 +123,25 @@ void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
>> trace->entries[trace->nr_entries++] = ULONG_MAX;
>> }
>>
>> +void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
>> +{
>> + struct stack_trace_data data;
>> + struct stackframe frame;
>> +
>> + data.trace = trace;
>> + data.skip = trace->skip;
>> + data.no_sched_functions = 0;
>> +
>> + frame.fp = regs->ARM_fp;
>> + frame.sp = regs->ARM_sp;
>> + frame.lr = regs->ARM_lr;
>> + frame.pc = regs->ARM_pc;
>> +
>> + walk_stackframe(&frame, save_trace, &data);
>> + if (trace->nr_entries < trace->max_entries)
>> + trace->entries[trace->nr_entries++] = ULONG_MAX;
>> +}
>> +
>> void save_stack_trace(struct stack_trace *trace)
>> {
>> save_stack_trace_tsk(current, trace);
>