下面是trace扩展的项目地址：

• https://github.com/fujitsu/crash-trace

如果已经编译安装过crash，可以直接编译，然后使用extend工具加载.

加载模块

crash> extend /mnt/crash-trace/trace.so
/mnt/crash-trace/trace.so: shared object loaded

crash> extend
SHARED OBJECT              COMMANDS
/mnt/crash-trace/trace.so  trace

输出缓冲区数据

crash> trace show
...
cpus=8
            bash-461   [002]   548.086834: function:             mutex_unlock
            bash-461   [002]   548.086847: function:             __mutex_unlock_slowpath
            bash-461   [002]   548.086849: function:             preempt_count_add
            bash-461   [002]   548.086849: function:             rcu_read_lock_any_held
            bash-461   [002]   548.086849: function:                rcu_read_lock_held_common
            bash-461   [002]   548.086849: function:                   rcu_lockdep_current_cpu_online
            bash-461   [002]   548.086849: function:             preempt_count_sub
            bash-461   [002]   548.086850: function:             syscall_exit_to_user_mode_prepare
            bash-461   [002]   548.086850: function:             exit_to_user_mode_prepare
            bash-461   [002]   548.086851: function:                fpregs_assert_state_consistent
            bash-461   [002]   548.086851: function:                switch_fpu_return
            bash-461   [002]   548.086862: function:             __x64_sys_dup2

导出到trace.dat

crash> trace dump -t

# trace-cmd report
...
cpus=8
            bash-461   [002]   548.086834: function:             mutex_unlock
            bash-461   [002]   548.086847: function:             __mutex_unlock_slowpath
            bash-461   [002]   548.086849: function:             preempt_count_add
            bash-461   [002]   548.086849: function:             rcu_read_lock_any_held
            bash-461   [002]   548.086849: function:                rcu_read_lock_held_common
            bash-461   [002]   548.086849: function:                   rcu_lockdep_current_cpu_online
            bash-461   [002]   548.086849: function:             preempt_count_sub
            bash-461   [002]   548.086850: function:             syscall_exit_to_user_mode_prepare

卸载

crash> extend /mnt/crash-trace/trace.so -u
/mnt/crash-trace/trace.so: shared object unloaded