@@ -152,6 +152,27 @@ static int save_trace(struct stackframe *frame, void *d)
return trace->nr_entries >= trace->max_entries;
}
+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->regs[29];
+ frame.sp = regs->sp;
+ frame.pc = regs->pc;
+#ifdef CONFIG_FUNCTION_GRAPH_TRACER
+ frame.graph = current->curr_ret_stack;
+#endif
+
+ walk_stackframe(current, &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)
{
struct stack_trace_data data;
Currently, enabling stacktrace of a kprobe events generates warning: echo stacktrace > /sys/kernel/debug/tracing/trace_options echo "p xhci_irq" > /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable save_stack_trace_regs() not implemented yet. ------------[ cut here ]------------ WARNING: CPU: 1 PID: 0 at ../kernel/stacktrace.c:74 save_stack_trace_regs+0x3c/0x48 Modules linked in: CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.8.0-rc4-dirty #5128 Hardware name: ARM Juno development board (r1) (DT) task: ffff800975dd1900 task.stack: ffff800975ddc000 PC is at save_stack_trace_regs+0x3c/0x48 LR is at save_stack_trace_regs+0x3c/0x48 pc : [<ffff000008126c64>] lr : [<ffff000008126c64>] pstate: 600003c5 sp : ffff80097ef52c00 Call trace: [<ffff000008126c64>] save_stack_trace_regs+0x3c/0x48 [<ffff00000817a0b0>] __ftrace_trace_stack+0x168/0x208 [<ffff00000817ad40>] trace_buffer_unlock_commit_regs+0x5c/0x7c [<ffff00000818d57c>] kprobe_trace_func+0x308/0x3d8 [<ffff00000818defc>] kprobe_dispatcher+0x58/0x60 [<ffff0000088d8cfc>] kprobe_breakpoint_handler+0xbc/0x18c [<ffff0000080851b8>] brk_handler+0x50/0x90 [<ffff000008081300>] do_debug_exception+0x50/0xbc This patch implements save_stack_trace_regs(), so that stacktrace of a kprobe events can be obtained. After this patch, there is no warning and we can see the stacktrace for kprobe events in trace buffer. more /sys/kernel/debug/tracing/trace <idle>-0 [004] d.h. 1356.000496: p_xhci_irq_0:(xhci_irq+0x0/0x9ac) <idle>-0 [004] d.h. 1356.000497: <stack trace> => xhci_irq => __handle_irq_event_percpu => handle_irq_event_percpu => handle_irq_event => handle_fasteoi_irq => generic_handle_irq => __handle_domain_irq => gic_handle_irq => el1_irq => arch_cpu_idle => default_idle_call => cpu_startup_entry => secondary_start_kernel => Tested-by: David A. Long <dave.long@linaro.org> Reviewed-by: James Morse <james.morse@arm.com> Signed-off-by: Pratyush Anand <panand@redhat.com> --- v1 to v2: Rebased with 4.8.0-rc4 v2 to v3: CONFIG_FUNCTION_GRAPH_TRACER fixup and improved commit log arch/arm64/kernel/stacktrace.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+)