本文已参与「新人创作礼」活动，一起开启掘金创作之路。
一、查看是否有挂载分区
cat /proc/mounts
二、驱动相关
c 代表字符型驱动 char类型 b代表块类型驱动 block类型
前面一个叫主设备号用于判断那个驱动，后面是次设备号，用于判断那个硬件
mek_8q:/ # ls -l /dev
total 12
drwx--x--x 2 root root 3380 2022-05-20 20:51 __properties__
crw-rw-rw- 1 root root 10, 125 2022-05-20 20:51 ashmem /*主设备号10 此次设备号 125*/
crw-rw-rw- 1 root root 10, 125 2022-05-20 20:51 ashmem15f99089-24f8-4f88-a9ad-3787ae2aa4d0
crw------- 1 root root 10, 235 2022-05-20 20:51 autofs
lrwxrwxrwx 1 root root 20 2022-05-20 20:51 binder -> /dev/binderfs/binder
drwxr-xr-x 3 root root 0 2022-05-20 20:51 binderfs
dr-xr-xr-x 3 system system 0 2022-05-20 20:51 blkio
drwxr-xr-x 6 root root 1540 2022-05-20 20:51 block
drwxr-xr-x 3 root root 60 2022-05-20 20:51 boringssl
drwxr-xr-x 3 root root 60 2022-05-20 20:51 bus
drwx--x--x 2 system system 60 2022-05-20 20:51 cgroup_info
crw------- 1 root root 5, 1 2022-05-20 20:51 console
三、查看log buffer size
logcat -g
mek_8q:/ # logcat -g
main: ring buffer is 16 MiB (359 KiB consumed), max entry is 5120 B, max payload is 4068 B
system: ring buffer is 16 MiB (371 KiB consumed), max entry is 5120 B, max payload is 4068 B
crash: ring buffer is 16 MiB (0 B consumed), max entry is 5120 B, max payload is 4068 B
kernel: ring buffer is 16 MiB (43 KiB consumed), max entry is 5120 B, max payload is 4068 B
四、在.mk文件里面添加打印
Android.mk
+++ b/Android.mk
@@ -2,6 +2,8 @@ LOCAL_PATH := $(call my-dir)
ifneq ($(BOARD_HAVE_BLUETOOTH_BCM),)
+$(warning "cluo---------the value of BOARD_HAVE_BLUETOOTH_BCM is $(BOARD_HAVE_BLUETOOTH_BCM)")
+
include $(CLEAR_VARS)
编译时打印
hardware/broadcom/libbt/Android.mk was modified, regenerating...
[ 41% 97/233] including hardware/broadcom/libbt/Android.mk ...
hardware/broadcom/libbt/Android.mk:5: warning: "cluo---------the value of BOARD_HAVE_BLUETOOTH_BCM is true"
[ 95% 222/233] including vendor/nxp-opensource/nn-imx/Android.mk ...
五、addr2line反编译
崩溃日志；
05-20 03:40:23.756 2098 2098 F DEBUG : #01 pc 0000000000265434 /system/lib64/libbluetooth.so (startup_timer_expired(void*)+188) (BuildId: 3fae33ca1eda89f10865aeb654a96422)
05-20 03:40:23.756 2098 2098 F DEBUG : #02 pc 0000000000336e48 /system/lib64/libbluetooth.so (alarm_ready_generic(alarm_t*, std::__1::unique_lock<std::__1::mutex>&)+400) (BuildId: 3fae33ca1eda89f1086)
05-20 03:40:23.756 2098 2098 F DEBUG : #03 pc 0000000000336c78 /system/lib64/libbluetooth.so (alarm_queue_ready(fixed_queue_t*, void*)+112) (BuildId: 3fae33ca1eda89f10865aeb654a96422)
05-20 03:40:23.756 2098 2098 F DEBUG : #04 pc 000000000033c090 /system/lib64/libbluetooth.so (internal_dequeue_ready(void*)+88) (BuildId: 3fae33ca1eda89f10865aeb654a96422)
05-20 03:40:23.756 2098 2098 F DEBUG : #05 pc 000000000033d714 /system/lib64/libbluetooth.so (run_reactor(reactor_t*, int)+388) (BuildId: 3fae33ca1eda89f10865aeb654a96422)
05-20 03:40:23.756 2098 2098 F DEBUG : #06 pc 000000000033d560 /system/lib64/libbluetooth.so (reactor_start(reactor_t*)+88) (BuildId: 3fae33ca1eda89f10865aeb654a96422)
05-20 03:40:23.756 2098 2098 F DEBUG : #07 pc 000000000033f088 /system/lib64/libbluetooth.so
反编译：
out/target/product/mek_8q$ addr2line -e symbols/system/lib64/libbluetooth.so 0000000000265434
system/bt/hci/src/hci_layer.cc:389
