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从我的previsou问题为什么模块无法加载？（/dev/scull0：没有这样的设备或地址）我设法通过加载模块/sbin/insmod，但在那之后，我已经注销了 dmesg：

[ 2765.707018] scull: loading out-of-tree module taints kernel.
[ 2765.707106] scull: module verification failed: signature and/or required key missing - tainting kernel
[ 2765.707929] Passed scull_init_module at 41 (debug info - successful load of init module)
[ 6027.843914] acer_wmi: Unknown function number - 8 - 1
[ 7347.683312] stack segment: 0000 [#1] SMP PTI
[ 7347.683323] CPU: 3 PID: 15280 Comm: rmmod Tainted: G           OE     4.19.0-9-amd64 #1 Debian 4.19.118-2
[ 7347.683326] Hardware name: Acer Swift SF314-52/Suntory_KL, BIOS V1.08 11/28/2017
/* start of the problem: */
[ 7347.683335] RIP: 0010:scull_trim+0x3a/0xa0 [scull]
[ 7347.683339] Code: 44 8b 77 0c 48 8b 2f 45 8d 66 ff 49 c1 e4 03 48 85 ed 75 16 eb 4b 48 8b 5d 08 48 89 ef e8 7e 38 f1 e1 48 89 dd 48 85 db 74 37 <48> 8b 7d 00 48 85 ff 74 e3 45 85 f6 7e 1a 31 db eb 04 48 83 c3 08

/*... output of all registers ...*/

[ 7347.683372] Call Trace:
[ 7347.683382]  cleanup_module+0x44/0x80 [scull]
[ 7347.683391]  __x64_sys_delete_module+0x190/0x2e0
[ 7347.683399]  do_syscall_64+0x53/0x110
[ 7347.683405]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 7347.683530] ---[ end trace c4b4a1cdb428d4b3 ]---
[ 7347.885914] RIP: 0010:scull_trim+0x3a/0xa0 [scull]
... /* again */ ...

在这里我可以观察到，混乱是由scull_trim（下面的源代码）引起的，内核触发strace来解决它（或者当内核Call Trace:出现问题时内核调用？）。

scull_trim：

 /*main structure */
 struct scull_dev {
 struct scull_qset *data; /*quantum repre*/
 int quantum; /*in bytes*/
 int qset; /*array size*/
 unsigned long size; /*total bytes in device*/
 struct cdev cdev; /*Char device structure*/
 };

/*representation of quantum*/
struct scull_qset {
void **data;
struct scull_qset *next;
};

/*-------------------------------------------------------------------------------------*/
int scull_trim(struct scull_dev *dev) {
    struct scull_qset *next, *dptr; /* next for loop, dptr = data pointer (index in loop) */
    int qset = dev->qset; /* get size of arrat */
    int i; /*index for second loop for quantum bytes */

    for(dptr = dev->data /*struct scull_qset*/; dptr ; dptr = next){
        if (dptr->data /*array of quantum*/) {
            for(i=0; i<qset; i++){
                kfree(dptr->data[i]); /*free each byte of array data[i]*/
            }
            kfree(dptr->data); /*free array pointer itself*/
            dptr->data = NULL; /*set array pointer to null pointer to avoid garbage*/
        }
        next = dptr->next;
        kfree(dptr); /* free pointer itself */
    }
    //setting new attributes for cleared dev
    dev->size = 0;
    dev->quantum = scull_quantum;
    dev->qset = scull_qset;
    dev->data = NULL;

    return 0;
}

该函数scull_trim基本上来自linux device driver, 3 edition，并且该函数的目的是在调用方法之前从设备中删除所有字节open。但是为什么它会导致dmesg错误，内核必须调用 strace 来解决它？

编辑：因为几乎不可能解决问题，所以我从 github 添加源（以及 dmesg 转储）： repo:scull device。请访问它以解决问题。

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