Re: [PATCH 0/1] MR2794: ntdll: add attribute "force_align_arg_pointer" to hanlder of signal on i386 & x86_64

[Fan WenJie (＠fanwenjie)]

On Thu May 11 16:09:42 2023 +0000, Alexandre Julliard wrote:
> > But initilize value of sp on signal stack is 16n instead of 16n-8.
> > Where are you seeing that? It sounds like a bug in your kernel/emulator.
> > dlls\ntdll\unix\server.c
static int init_thread_pipe(void)
{
    int reply_pipe[2];
    stack_t ss;

    ss.ss_sp    = get_signal_stack();
    ss.ss_size  = signal_stack_size;
    ss.ss_flags = 0;
    sigaltstack( &ss, NULL );

    if (server_pipe( reply_pipe ) == -1) server_protocol_perror( "pipe" );
    if (server_pipe( ntdll_get_thread_data()->wait_fd ) == -1) server_protocol_perror( "pipe" );
    wine_server_send_fd( reply_pipe[1] );
    wine_server_send_fd( ntdll_get_thread_data()->wait_fd[1] );
    ntdll_get_thread_data()->reply_fd = reply_pipe[0];
    return reply_pipe[1];
}

get_signal_stack() return a value of 16n

signal_stack_size = 0x10000 - 0x3800 is also 16n

so value of stack top is 16n

but on x86_64, value of sp at begin of signal handler must be 16n-8

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/2794#note_32531