AM335x 添加4G模块 使用usb串口 内存泄漏

我使用的是am335x 的 Linux 4.14 内核，在移植移远4g模块EC20时出现了如下问题：

我能够在设备中发现ttyUSB0~3，并且可以使用ppp拨号成功拨号，但是在拨号成功一小段时间后系统就会发生内存泄漏之后死机，我搜索后发现是在内核driver/usb/core/urb.c文件中的usb_anchor_urb函数中的list_add_tail函数发生的问题，我不知道发生了什么，是系统的bug吗，我是安装模块安装说明书进行的配置，之前在4.1.18内核中可以正常加载4g模块，并不会发生这个问题，希望有人可以解答一下，附问题如下：

[ 99.259592] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[ 99.268187] pgd = db0d8000
[ 99.271068] [00000000] *pgd=00000000
[ 99.274892] Internal error: Oops: 805 [#1] PREEMPT ARM
[ 99.280356] Modules linked in:
[ 99.283632] CPU: 0 PID: 97 Comm: sd-resolve Tainted: G W 4.14.79-ge669d52447 #37
[ 99.292686] Hardware name: Generic AM33XX (Flattened Device Tree)
[ 99.299163] task: dc59de00 task.stack: db0c8000
[ 99.304012] PC is at usb_anchor_urb+0x9c/0x128
[ 99.308767] LR is at wake_up_klogd+0x5c/0x90
[ 99.313308] pc : [<c05fb148>] lr : [<c0168eec>] psr: 200e0093
[ 99.319966] sp : db0c9858 ip : 00000007 fp : db0c987c
[ 99.325519] r10: 00000043 r9 : c0d16680 r8 : db0c8000
[ 99.331074] r7 : 200e0093 r6 : dc5d8d9c r5 : dc554404 r4 : dc5d8d80
[ 99.338011] r3 : 00000000 r2 : 00000a05 r1 : 00000000 r0 : c0b0d47c
[ 99.344953] Flags: nzCv IRQs off FIQs on Mode SVC_32 ISA ARM Segment none
[ 99.352629] Control: 10c5387d Table: 9b0d8019 DAC: 00000051
[ 99.358735] Process sd-resolve (pid: 97, stack limit = 0xdb0c8210)
[ 99.365303] Stack: (0xdb0c9858 to 0xdb0ca000)
[ 99.369941] 9840: 00000000 db0c9868
[ 99.378644] 9860: 00000000 dc5543e0 dc5d8d80 00000043 db0c98d4 db0c9880 c0621814 c05fb0b8
[ 99.387343] 9880: db0c989c db0c9890 00000043 dc5543c0 a00e0013 01080020 dc5f4000 dc5df180
[ 99.396042] 98a0: db3e80b0 dc554400 00000040 c0621678 db1dd60e 00000040 00000001 c0924ff8
[ 99.404745] 98c0: db3e8000 00000001 db0c98ec db0c98d8 c061b654 c0621684 00000043 db1dd60e…

yongqing wang：

对比一下两个内核整个USB的目录下的文件看看

ping gong：

回复 yongqing wang:

我对比过了，是相同的，我使用gdb查看错误报告发现错误定位在/include/linux/compiler.h文件，具体如下：

root@gong:/opt/ti-am335x-20190514/board-support/linux# arm-linux-gnueabihf-gdb vmlinux

GNU gdb (GDB) 8.0

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License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>

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There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details.

This GDB was configured as "–host=x86_64-arago-linux –target=arm-linux-gnueabi".

Type "show configuration" for configuration details.

For bug reporting instructions, please see:<http://www.gnu.org/software/gdb/bugs/>.

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For help, type "help".

Type "apropos word" to search for commands related to "word"…

Reading symbols from vmlinux…done.

(gdb) l *(usb_anchor_urb+0x9c)

0xc05fb148 is in usb_anchor_urb (./include/linux/compiler.h:211).

206 static __always_inline void __write_once_size(volatile void *p, void *res, int size)

207 {

208 switch (size) {

209 case 1: *(volatile __u8 *)p = *(__u8 *)res; break;

210 case 2: *(volatile __u16 *)p = *(__u16 *)res; break;211 case 4: *(volatile __u32 *)p = *(__u32 *)res; break;

212 case 8: *(volatile __u64 *)p = *(__u64 *)res; break;

213 default:

214 barrier();

215 __builtin_memcpy((void *)p, (const void *)res, size);

(gdb)