Re: [PATCH 3/3] Cygwin: Add loaded module base address list to stackdump

[Corinna Vinschen <corinna-cygwin@cygwin.com>]

On Nov  3 17:02, Jon Turney wrote:
> On 29/10/2022 09:32, Corinna Vinschen wrote:
> > On Oct 28 16:05, Jon Turney wrote:
> > > This adds an extra section to the stackdump, which lists the loaded
> > > modules and their base address.  This is perhaps useful as it makes it
> > > immediately clear if RandomCrashInjectedDll.dll is loaded...
> > > 
> > > XXX: It seems like the 'InMemoryOrder' part of 'InMemoryOrderModuleList' is a lie?
> > 
> > Probably just an alternative fact...
> 
> Yeah.  I did stared a bit at the code wondering if the structure layouts
> were incorrect so we were somehow traversing one of the other module lists
> with a different ordering, but everything looks correct.
> 
> The attached might be a good idea, then, to ensure that module+offset is
> calculated correctly.

Good idea, please push.


Corinna

> From ea47826047e8bb175b1b0e0286d7d7b8cf15c7fe Mon Sep 17 00:00:00 2001
> From: Jon Turney <jon.turney@dronecode.org.uk>
> Date: Tue, 1 Nov 2022 14:01:08 +0000
> Subject: [PATCH] Cygwin: Handle out of order modules for module offsets in
>  stackdump
> 
> Improve address to module+offset conversion, to work correctly in the
> presence of out-of-order elements in InMemoryOrderModuleList.
> 
> Fixes: d59651d4
> ---
>  winsup/cygwin/exceptions.cc | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/winsup/cygwin/exceptions.cc b/winsup/cygwin/exceptions.cc
> index 8cc454c90..c3433ab94 100644
> --- a/winsup/cygwin/exceptions.cc
> +++ b/winsup/cygwin/exceptions.cc
> @@ -342,11 +342,13 @@ prettyprint_va (PVOID func_va)
>      {
>        PLDR_DATA_TABLE_ENTRY mod = CONTAINING_RECORD (x, LDR_DATA_TABLE_ENTRY,
>  						     InMemoryOrderLinks);
> -      if (mod->DllBase > func_va)
> +      if ((func_va < mod->DllBase) ||
> +	  (func_va > (PVOID)((DWORD_PTR)mod->DllBase + mod->SizeOfImage)))
>  	continue;
>  
>        __small_sprintf (buf, "%S+0x%x", &mod->BaseDllName,
>  		       (DWORD_PTR)func_va - (DWORD_PTR)mod->DllBase);
> +      break;
>      }
>  
>    return buf;
> -- 
> 2.38.1
>