Hi,
From what is visible in the code excerpt you added, you don't allocate any memory where the variable res points to.
If this is the reason, replacing 'char *res;' by 'char res[20];' or adding the line
'res = (char *) malloc(20;' will solve the problem.
Israel Fernandez wrote:
> Hi:
> I have a LKM with a /proc file to communicate a user land process with.
> this is the read function in my LKM:
> _____________________________________
> copy_to_user(buf, strBuf, len);
> put_user(0, &buf[len]);
> ...
> return len
>
> and this is what i do in the userland:
>
> int fd = open("/proc/my_proc", O_RDONLY);
> char *res;
> read(fd, res, 20);
> close(fd);
> _____________________________________
> it can read ok, but i get the following messages:
>
> 01913: symbol=exit; lookup in file=/home/..././savld /*This is my user
> land proc*/
> 01913: symbol=exit; lookup in file=/usr/lib/libstdc++-libc6.2-2.so.3
> ...
> lookup 0x080048000 0x00000238 -> 0x40092000 0x000e04f0 /1 close
> 01913: symbol=exit; lookup in file=/home/..././savld /*This is my user
> land proc*/
> 01913: symbol=exit; lookup in file=/usr/lib/libstdc++-libc6.2-2.so.3
> ...
> Segmentation Fault
>
> can somebody tell what's wrong?
>
> --
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