[Bug 47812] New: Cygwin's strace.exe crashes due to custom TLS corruption

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=47812

Bug ID: 47812
           Summary: Cygwin's strace.exe crashes due to custom TLS
                    corruption
           Product: Wine
           Version: 4.16
          Hardware: x86
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: -unknown
          Assignee: [e-mail]
          Reporter: [e-mail]
      Distribution: ---

This is not (as far as I can see) a Wine bug, and it's certainly not worth
fixing, but I'm writing this down here so that someone doesn't go through the
same work to figure it out...

Cygwin, for whatever reason, reimplements TLS by storing things at a fixed
offset from the stack base (i.e. NtCurrentTeb()->Tib.StackBase). Somewhere
along the line this gets corrupted, specifically the _locale member.

I think the assumptions made at [1] with regard to alloca() are just bogus.
There's no guarantee that the returned memory will contain wholly the custom
TLS slot, and I'm not particularly sure why they expect it to remain untouched
after DLL_PROCESS_ATTACH returns.

[1] https://github.com/Alexpux/Cygwin/blob/master/winsup/cygwin/init.cc#L90

[Bug 47812] Cygwin's strace.exe crashes due to custom TLS corruption

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=47812

Zebediah Figura  changed:

What    |Removed                     |Added
----------------------------------------------------------------------------
      Fixed by SHA1|                            |25b093f3845a0ae1b2e2fe1c070
                   |                            |1e98064f8e8d6
          Component|-unknown                    |ntdll
                URL|                            |http://cygwin.com/setup-x86
                   |                            |_64.exe
         Resolution|---                         |FIXED
             Status|NEW                         |RESOLVED
           Keywords|                            |download

--- Comment #1 from Zebediah Figura  ---
Today, surprisingly enough, I believe this bug has been fixed. We now have a
separate kernel stack, which means that while Cygwin is still doing something
very fragile, we are no longer touching the stack between DLL attach and thread
initialization, and as a result Cygwin's custom TLS does not get corrupted.

Unfortunately I didn't save the original Cygwin version or command I used to
reproduce this, but I tested with the following and encountered no crashes,
with strace version 3.2.0, echo 8.26, and Cygwin version 2.908.

wine strace.exe --output hello-strace -f echo.exe 'world hello' > hello.out

Fixed by
https://source.winehq.org/git/wine.git/commitdiff/25b093f3845a0ae1b2e2fe1c0701e98064f8e8d6
for x86_64, and its parent for i386.

[Bug 47812] Cygwin's strace.exe crashes due to custom TLS corruption

[WineHQ Bugzilla]

https://bugs.winehq.org/show_bug.cgi?id=47812

Alexandre Julliard  changed:

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

--- Comment #2 from Alexandre Julliard  ---
Closing bugs fixed in 6.11.