kernel patch needed for wine?

[Garrett Cooper]

2010/6/30 Alexander Kabaev <kabaev at gmail.com>:
> On Wed, 30 Jun 2010 14:42:47 -0700
> Garrett Cooper <yanefbsd at gmail.com> wrote:
>
>> On Wed, Jun 30, 2010 at 2:22 PM, Sam Fourman Jr. <sfourman at gmail.com>
>> wrote:
>> > On Wed, Jun 30, 2010 at 11:26 AM, Garrett Cooper
>> > <yanefbsd at gmail.com> wrote:
>> >> On Wed, Jun 30, 2010 at 8:43 AM, Sam Fourman Jr.
>> >> <sfourman at gmail.com> wrote:
>> >>>> Which patch ? icebp generates the SIGTRAP on latest 8-stable,
>> >>>> verified by the following trivival assembler program:
>> >>>>        .text
>> >>>>        .globl  main
>> >>>> main:
>> >>>>        .byte   0xf1
>> >>>>        xorl    %edi,%edi
>> >>>>        call    exit
>> >>>>
>> >>>
>> >
>> > Here is the C program that the linux people used as a test case.
>> >
>> > ***************************************************************
>> > #include <stdio.h>
>> > #include <signal.h>
>> >
>> >
>> >
>> > void trap_handler(int sig)
>> > {
>> >        printf("trapped\n");
>> > }
>> >
>> >
>> > /*
>> >  * icebp
>> >  * ret
>> >  */
>> > char icebp_func[] = "\xf1\xc3";
>> > typedef void (*icebp_call)(void);
>> >
>> > int main(int argc, char **argv)
>> > {
>> >        icebp_call func = (icebp_call)icebp_func;
>> >
>> >        signal(SIGTRAP, trap_handler);
>> >
>> >        func();
>> >
>> >        return 0;
>> > }
>> >
>> > ***************************************************************
>> >
>> > My question is why doe the above code not print trapped on amd64?
>> >
>> > FreeBSD 8.1 i386 this code prints "Trapped" as intended
>> > FreeBSD 8.1 amd64 this code prints "Segmentation fault: 11"
>> > FreeBSD 8.1 amd64 chrooted to 32bit prints "Segmentation fault"
>> >
>> > I did verify that from Linux amd64 this works and prints "Trapped"
>> > uname -a
>> > Linux workstation 2.6.32-23-generic #37-Ubuntu SMP Fri Jun 11
>> > 08:03:28 UTC 2010 x86_64 GNU/Linux
>>
>> Hmmm... I've seen similar whackiness with Linux and signals, but
>> that's a different thing entirely (it was rt signals vs non-rt
>> signals).
>>
>> Here's a modified version of the testcase (wanted to make sure that
>> things were sane):
>>
>> $ cat test_sigtrap.c
>> #include <err.h>
>> #include <signal.h>
>> #include <stdio.h>
>>
>> int trapped = 0;
>>
>> void trap_handler(int sig)
>> {
>>       trapped = 1;
>> }
>>
>>
>> /*
>>  * icebp
>>  * ret
>>  */
>> char icebp_func[] = "\xf1\xc3";
>> typedef void (*icebp_call)(void);
>>
>> int main(int argc, char **argv)
>> {
>>       icebp_call func = (icebp_call)icebp_func;
>>
>>       if (signal(SIGTRAP, trap_handler) == SIG_ERR)
>>               err(1, "signal");
>>
>>       func();
>>
>>       if (trapped)
>>               printf("Admiral Ackbar: it's a trap!\n");
>>
>>       return 0;
>> }
>>
>> Ran it and it segfaulted on CURRENT:
>>
>
> Now make icebp_func const and observe the program start working. The
> test case is broken as written, because icebp_func array is writable,
> so in ends up in a non-const part of .bss, which is not marked as
> executable and rightfully causes SIGSEGV when jumped to.

Which means that Linux is broken in this regard because it's loading
data as text, not data as data and text as text?
Thanks,
-Garrett