[Bug 39570] New: Multiple application crash handlers fail to load symbol information using 'dbghelp.SymLoadModule64', reporting 'dbghelp:validate_addr64 Unsupported address 0xfffffffffxxxxxxx'

[wine-bugs at winehq.org]

https://bugs.winehq.org/show_bug.cgi?id=39570

            Bug ID: 39570
           Summary: Multiple application crash handlers fail to load
                    symbol information using 'dbghelp.SymLoadModule64',
                    reporting 'dbghelp:validate_addr64 Unsupported address
                    0xfffffffffxxxxxxx'
           Product: Wine
           Version: 1.7.54
          Hardware: x86-64
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P2
         Component: dbghelp
          Assignee: wine-bugs at winehq.org
          Reporter: focht at gmx.net
      Distribution: ---

Hello folks,

the issue/question was raised in
https://bugs.winehq.org/show_bug.cgi?id=32237#c15

--- quote ---
I did try 2012 this time and I end up crashing

fixme:dbghelp:validate_addr64 Unsupported address fffffffff33a0000
err:seh:raise_exception Unhandled exception code c0000005 flags 0 addr
0x7bc3db51

What's wrong with the address?
--- quote ---

Searching the Internet reveals this pattern/message many times - also in Wine
Bugzilla - but no or even incorrect explanation - until now ;-)

On 64-bit Linux machines, the Wine loader allows 32-bit dlls being mapped at
high >2GB, >3GB address ranges in 32-bit processes, not having certain (design)
restrictions of 32-bit process address space layout on 64-bit Windows machines
(even with /LARGEADDRESSWARE).

Good case, 32-bit Wine builtin dll mapped < 2 GiB virtual address space range:

--- snip ---
...
0009:Call PE DLL (proc=0x7e1b6838,module=0x7e1b0000
L"wsock32.dll",reason=PROCESS_ATTACH,res=0x1) 
...
0027:Call dbghelp.SymLoadModule64(ffffffff,00000000,0b36a960
"C:\\windows\\system32\\wsock32.dll",0b36a988
"wsock32.dll",7e1b0000,00000000,0000e000) ret=005eff32
0027:trace:dbghelp:SymLoadModuleEx (0xffffffff (nil)
"C:\\windows\\system32\\wsock32.dll" "wsock32.dll" 7e1b0000 0000e000 (nil)
00000000) 
...
0027:trace:dbghelp:SymLoadModuleExW (0xffffffff (nil)
L"C:\\windows\\system32\\wsock32.dll" L"wsock32.dll" 7e1b0000 0000e000 (nil)
00000000) 
...
0027:trace:dbghelp:elf_load_file Processing elf file
'L"/home/focht/projects/wine/wine.repo/install/bin/../lib/wine/wsock32.dll.so"'
at 7e1a2000 
...
0027:Ret  dbghelp.SymLoadModule64() retval=7e1b0000 ret=005eff32 
--- snip ---

Bad case, 32-bit Wine builtin dll mapped near end of 4 GiB virtual address
space range:

--- snip ---
...
0009:Call PE DLL (proc=0xf734e3fc,module=0xf72f0000
L"winex11.drv",reason=PROCESS_ATTACH,res=(nil)) 
...
0027:Call dbghelp.SymLoadModule64(ffffffff,00000000,0b36a960
"C:\\windows\\system32\\winex11.drv",0b36a988
"winex11.drv",f72f0000,ffffffff,00090000) ret=005eff32
0027:trace:dbghelp:SymLoadModuleEx (0xffffffff (nil)
"C:\\windows\\system32\\winex11.drv" "winex11.drv" fffffffff72f0000 00090000
(nil) 00000000)
"winex11.drv",ffffffff,2d053b40,0000000c) ret=edbc2fa6
...
0027:trace:dbghelp:SymLoadModuleExW (0xffffffff (nil)
L"C:\\windows\\system32\\winex11.drv" L"winex11.drv" fffffffff72f0000 00090000
(nil) 00000000)
0027:fixme:dbghelp:validate_addr64 Unsupported address fffffffff72f0000  
...
0027:Ret  dbghelp.SymLoadModule64() retval=00000000 ret=005eff32 
--- snip ---

In this specific case, the game registered an own crash handler which dumps
various debugging information in case of a crash.

'dbghelp.SymLoadModule64' is called by the custom crash handler.

Source:
https://source.winehq.org/git/wine.git/blob/1fa7710ff92dd9555b2b4753e22ce5fc7629cab9:/dlls/dbghelp/module.c#l656

--- snip ---
 656 DWORD64 WINAPI SymLoadModule64(HANDLE hProcess, HANDLE hFile, PCSTR
ImageName,
 657                                PCSTR ModuleName, DWORD64 BaseOfDll, DWORD
SizeOfDll)
 658 {
 659     return SymLoadModuleEx(hProcess, hFile, ImageName, ModuleName,
BaseOfDll, SizeOfDll,
 660                            NULL, 0);
 661 }
--- snip ---

So how does high DWORD of 'BaseOfDll' parameter get the 0xffffffff value?

A few caller frames up in the app crash handler:

--- snip ---
...
005F06D6   8B55 D0          MOV EDX,DWORD PTR SS:[EBP-30]
005F06D9   8B45 CC          MOV EAX,DWORD PTR SS:[EBP-34]
005F06DC   8B4D F8          MOV ECX,DWORD PTR SS:[EBP-8]
005F06DF   52               PUSH EDX
005F06E0   99               CDQ
005F06E1   52               PUSH EDX            ; high DWORD BaseOfDll
005F06E2   50               PUSH EAX            ; low DWORD BaseOfDll
005F06E3   8B45 FC          MOV EAX,DWORD PTR SS:[EBP-4]
005F06E6   50               PUSH EAX
005F06E7   51               PUSH ECX
005F06E8   8B4D E8          MOV ECX,DWORD PTR SS:[EBP-18]
005F06EB   56               PUSH ESI
005F06EC   E8 EFF7FFFF      CALL A_Slower.005EFEE0
...
--- snip ---

'winex11.drv' -> 0xf72f0000

Since the highest bit in low 32-bit 'BaseOfDll' DWORD is set, the 'CDQ'
instruction copies the sign (bit 31) of the value in the EAX register into
every bit position in the EDX register.

Voila - you get the 0xffffffff EDX value which is then propagated through the
caller chain as high 32-bit 'BaseOfDll' DWORD to 'dbghelp.SymLoadModule64',
leading to symbol load failure and fixme/warning messages.

This should be fixed, allowing symbol information even for dlls mapped in high
address range to be loaded.

$ wine --version
wine-1.7.54-261-g61c49bd

Regards

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