printk bug

[YWHyuk]

printk %s format dosen't print correct string

[YWHyuk]

/kernel/vsprintf.c

165             len = strlen(s); <------------------------- Buggy
166             if (precision < 0)
167                 precision = len;
168             else if (len > precision)
169                 len = precision;
170
171             if (!(flags & LEFT))
172                 while (len < field_width--)
173                     *str++ = ' ';
174             for (i = 0; i < len; ++i)
175                 *str++ = *s++;
176             while (len < field_width--)
177                 *str++ = ' ';
178             break;

/kernel/vsprintf.dis

01 mov    (%edi),%edi
02 mov    $0xffffffff,%ecx
03 mov    $0x0,%eax
04 cld 
05 repnz scas %es:(%edi),%al 
06 not    %ecx
07 dec    %ecx 
08 mov    0x8(%esp),%eax
09 test   %eax,%eax
10 js     3da <vsprintf+0x1cd>
11 cmp    %eax,%ecx
12 jle    3da <vsprintf+0x1cd>
13 mov    %eax,%ecx
14 test   $0x10,%dl
15 je     416 <vsprintf+0x209>
16 test   %ecx,%ecx
17 jle    3f6 <vsprintf+0x1e9>
18 mov    $0x0,%eax
19 mov    (%edi,%eax,1),%dl

1. In line 4, strlen inline function starts.
2. In line 7, strlen inline function ends.

In line 5, edi register's value is changed. But edi(corrupted) is used in line 19