| Issue |
170291
|
| Summary |
stack 64 bit num misalignment caused by -fstack-protector-strong
|
| Labels |
|
| Assignees |
|
| Reporter |
dongwei123wh
|
I used clang on armv7 arch(little endian), when I add compiler option -fstack-protector-strong, the sprinf_s for uint64_t num is abnormal, demo as below:
sprintf_s(buffer, bufferLen, formar, 0x3c6ULL);
..
void sprintf_s(buffer, bufferLen, formar, ...)
{
...
va_list args;
va_start(args, format);
u64val = va_arg(args, long long int); // get wrong num 0x0000036c 00000015, not 0x00000000 000003c6，
....
}
The reason is 0x3c6 address is not 64 bit aligned address， so va_arg get wrong address
stack data like： 00000015 0000036c 00000000
so, Why does this happen? and how can it be resolved?
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