[Bug 27929] New: Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

Summary: Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion
                    with Xcode 4.1
           Product: Wine
           Version: 1.3.25
          Platform: x86-64
        OS/Version: other
            Status: UNCONFIRMED
          Severity: major
          Priority: P2
         Component: -unknown
        AssignedTo: [e-mail]
        ReportedBy: [e-mail]

I have compiled Wine 1.3.25 on Mac OS X 10.7, with the latest developer tools
installed (Xcode 4.1).
Trying to launch any wine program, even winemine, results in it crashing with
the message "Bus error: 10".
Running wine inside gdb, and with WINEDEBUG=+relay, shows that the crash occurs
while doing:

0045:Call user32.LoadIconA(403b0000,403b5a84 "WINEMINE") ret=403b1899

Specifically, it crashes inside create_alpha_bitmap, soon after the call to
StretchDIBits returns, inside the loop that does alpha premultiplication. By
disassembling I found that the crash occurs in the line

ptr[0] = ptr[0] * alpha / 255;

when attempting to write back the value into ptr[0]. It occurs on the very
first iterations of the loop.

I tried googling a bit, and this seems to be the same problem that was
discussed here:
http://www.winehq.org/pipermail/wine-devel/2011-January/088553.html

But that conversation was back in January, and it's unclear if any resolution
was reached.
Anyway, since this problem seems to make Wine completely unusable on Lion, and
can be reproduced entirely within wine, I think it should be considered both
easy to reproduce (as long as you have access to a Mac) and very urgent to fix

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

[e-mail] changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|-unknown                    |user32

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #1 from Alexandre Julliard  2011-07-28 10:08:43 CDT ---
That's a DIB section exception, it should be caught and handled. It sounds like
your signal handlers are broken, probably a compiler issue. Building Wine on
Lion is not recommended at this point unless you know what you are doing.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #2 from [e-mail] 2011-07-28 10:54:00 CDT ---
(In reply to comment #1)
> That's a DIB section exception, it should be caught and handled. It sounds like
> your signal handlers are broken, probably a compiler issue. Building Wine on
> Lion is not recommended at this point unless you know what you are doing.

And if you knew what you were doing, what would you do? Is this problem being
discussed anywhere? I might be able to help.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #3 from Alexandre Julliard  2011-07-28 11:00:23 CDT ---
(In reply to comment #2)
> And if you knew what you were doing, what would you do? Is this problem being
> discussed anywhere? I might be able to help.

Not really. I played a little with the developer preview but other priorities
interfered. Essentially you'll have to debug it and figure out what's wrong
with the signal handling.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #4 from [e-mail] 2011-07-28 11:16:13 CDT ---
(In reply to comment #3)
> (In reply to comment #2)
> > And if you knew what you were doing, what would you do? Is this problem being
> > discussed anywhere? I might be able to help.
>
> Not really. I played a little with the developer preview but other priorities
> interfered. Essentially you'll have to debug it and figure out what's wrong
> with the signal handling.

signal_init_process is called, and the disassembly looks right: it seems to be
calling sigaction with the the correct pointer to segv_handler. However,
segv_handler is not called when the signal is received. I'll keep
investigating.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #5 from [e-mail] 2011-07-28 15:11:30 CDT ---
(In reply to comment #4)
> signal_init_process is called, and the disassembly looks right: it seems to be
> calling sigaction with the the correct pointer to segv_handler. However,
> segv_handler is not called when the signal is received. I'll keep
> investigating.

Actually, the signal handler is probably getting called, but gdb on OS X messes
us the translation between mach exceptions (EXC_BAD_ACCESS in this case) and
UNIX signals (SIGBUS), so it cannot be used to step into signal handlers.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #6 from [e-mail] 2011-07-28 23:04:07 CDT ---
(In reply to comment #5)
> (In reply to comment #4)
> > signal_init_process is called, and the disassembly looks right: it seems to be
> > calling sigaction with the the correct pointer to segv_handler. However,
> > segv_handler is not called when the signal is received. I'll keep
> > investigating.
>
> Actually, the signal handler is probably getting called, but gdb on OS X messes
> us the translation between mach exceptions (EXC_BAD_ACCESS in this case) and
> UNIX signals (SIGBUS), so it cannot be used to step into signal handlers.

Ok, the solution to this problem is to give gdb the obscure command "set
dont-handle-bad-access 1" before running the program. This stops gdb from
intercepting the Mach exception, allowing the normal translation into a UNIX
signal to work, and then the signal handler is called.

This does not solve the crash, but at least should make it much easier to
debug.
After doing this and setting a breakpoint at the beginning of segv_handler, I
was able to step through its assembly. It seems to be working correctly.
Indeed, I can just give the "continue" command a few times, to go through the
page faults, and eventually the program runs correctly!

In fact, I can set "handle SIGBUS nostop", delete the breakpoint, and the
program runs correctly in gdb. Strange.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #7 from [e-mail] 2011-08-01 07:21:22 CDT ---
create_alpha_bitmap is a red herring, it seems. The real crash occurs while
loading libraries, and the signal handlers is not called because it has not
even been installed at that point. Unfortunately, this crash does not occur
when running with gdb, so it's hard to debug.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #8 from [e-mail] 2011-08-01 07:54:46 CDT ---
(In reply to comment #7)
> create_alpha_bitmap is a red herring, it seems. The real crash occurs while
> loading libraries, and the signal handlers is not called because it has not
> even been installed at that point. Unfortunately, this crash does not occur
> when running with gdb, so it's hard to debug.

Using DYLD_PRINT_LIBRARIES and export DYLD_PRINT_INITIALIZERS, wine built on
10.7 behaves like this:

----8<----
dyld: loaded: /usr/X11/lib/libXdmcp.6.dylib
dyld: calling initializer function 0x95667700 in /usr/lib/libSystem.B.dylib
Bus error: 10
----8<----

The one build on 10.6 (but run on the same 10.7 machine) does:

----8<----
dyld: loaded: /usr/X11/lib/libXdmcp.6.dylib
dyld: calling initializer function 0x95667700 in /usr/lib/libSystem.B.dylib
dyld: calling initializer function 0x957090c0 in /usr/lib/libc++.1.dylib
----8<----

and continues with the other initializers. So it seems that the crash really
occurs inside libSystem's initializer, which is the first to be called.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #9 from [e-mail] 2011-08-01 07:58:33 CDT ---
Using the wine executable built on 10.6 with the libraries built on 10.7
doesn't crash. This reduces the target enormously!

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #10 from [e-mail] 2011-08-01 13:29:48 CDT ---
Created an attachment (id=35775)
 --> (http://bugs.winehq.org/attachment.cgi?id=35775)
makes wine link correctly on lion

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #11 from [e-mail] 2011-08-01 13:30:48 CDT ---
This fixes the problem. Can I change the bug directly from unconfirmed to
fixed? When can I expect this patch to make it into a dev release?

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #12 from Alexandre Julliard  2011-08-01 13:47:55 CDT ---
A bug is not fixed until the patch is committed, and patches have to be sent to
wine-patches to be applied. Of course it would really need a configure check to
determine if the flag is necessary (or even supported).

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

--- Comment #13 from [e-mail] 2011-08-02 08:18:47 CDT ---
(In reply to comment #12)
> A bug is not fixed until the patch is committed, and patches have to be sent to
> wine-patches to be applied. Of course it would really need a configure check to
> determine if the flag is necessary (or even supported).

Done.

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

Austin English  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED

--- Comment #14 from Austin English  2011-08-02 14:29:52 CDT ---
(In reply to comment #13)
> (In reply to comment #12)
> > A bug is not fixed until the patch is committed, and patches have to be sent to
> > wine-patches to be applied. Of course it would really need a configure check to
> > determine if the flag is necessary (or even supported).
>
> Done.

Fixed by
http://source.winehq.org/git/wine.git/commitdiff/0b5dcbafea44bf68ec72494cc9f...

[Bug 27929] Bus error in create_alpha_bitmap on Mac OS X 10.7 Lion with Xcode 4.1

http://bugs.winehq.org/show_bug.cgi?id=27929

Alexandre Julliard  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |CLOSED

--- Comment #15 from Alexandre Julliard  2011-08-05 12:38:10 CDT ---
Closing bugs fixed in 1.3.26.