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authorLin Yongting <linyongting@gmail.com>2014-05-04 16:27:41 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2014-05-30 01:12:32 +0100
commit9c986661638c69772f5479c4715061239ec61b29 (patch)
tree01d88c6ddbef930c205f0549203dbc9a6efecb00
parent2961b4bf70f833f16d522823ac16c5bb9e277ef7 (diff)
downloadop-kernel-dev-9c986661638c69772f5479c4715061239ec61b29.zip
op-kernel-dev-9c986661638c69772f5479c4715061239ec61b29.tar.gz
ARM: 8049/1: ftrace/add save_stack_trace_regs() implementation
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 <linyongting@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
-rw-r--r--arch/arm/kernel/stacktrace.c19
1 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm/kernel/stacktrace.c b/arch/arm/kernel/stacktrace.c
index 5a80ddf..f065eb05 100644
--- a/arch/arm/kernel/stacktrace.c
+++ b/arch/arm/kernel/stacktrace.c
@@ -149,6 +149,25 @@ static noinline void __save_stack_trace(struct task_struct *tsk,
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_tsk(struct task_struct *tsk, struct stack_trace *trace)
{
__save_stack_trace(tsk, trace, 1);
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