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

[Jon Turney <jon.turney@dronecode.org.uk>]

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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.

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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