Bad Command alignment #291
Description
Lines 95 to 102 in 38bd9b3
This function moves prev size along which can and will cause unalignment and potential errors.
On ARM devices this causes a SIGBUS.
The people who helped me figure this out suggested this fix
static Command* push_command(int type, int size) {
+ size_t alignment = alignof(max_align_t) - 1;
+ size = (size + alignment) & ~alignment; // forward align to 4
Command *cmd = (Command*) (command_buf + command_buf_idx);
int n = command_buf_idx + size;
if (n > COMMAND_BUF_SIZE) {
fprintf(stderr, "Warning: (" __FILE__ "): exhausted command buffer\n");
return NULL;
}
command_buf_idx = n;
memset(cmd, 0, sizeof(Command));
cmd->type = type;
cmd->size = size;
return cmd;
}But alignof and max_align_t have been introduced with C11 so it might be of interest to replace the alignof with a static alignment of either 4 or 16 to be safe