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); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
