Crash Dump Analysis Patterns (Part 291)
Thursday, March 14th, 2024Generative AI LLM models such as GPT-4 are very good at producing Annotated Stack Traces. This is similar to Message Annotations trace and log analysis pattern. Below are two examples from ChatGPT:
Explain this stack trace fragment line by line:
06 ffffa784`8ee7db20 fffff804`0516bbf2 nt!IofCallDriver+0x55
07 ffffa784`8ee7db60 fffff804`0516b9d2 nt!IopSynchronousServiceTail+0x1d2
08 ffffa784`8ee7dc10 fffff804`0516ad36 nt!IopXxxControlFile+0xc82
09 ffffa784`8ee7dd40 fffff804`04e28775 nt!NtDeviceIoControlFile+0x56
0a ffffa784`8ee7ddb0 00007ffe`4d263834 nt!KiSystemServiceCopyEnd+0x25
0b 0000009b`cc0fedd8 00007ffe`4a893ffb ntdll!NtDeviceIoControlFile+0x14
0c 0000009b`cc0fede0 00007ffe`4bb95f91 KERNELBASE!DeviceIoControl+0x6b
0d 0000009b`cc0fee50 00007ff7`6544342f KERNEL32!DeviceIoControlImplementation+0x81
This stack trace appears to be from the Windows operating system, showing a series of function calls related to an I/O operation, specifically a device I/O control operation (DeviceIoControl). The stack trace is displayed in reverse chronological order, meaning the most recent call is shown first. Here’s a line-by-line explanation:
Lines 06 to 09 (nt!…): These lines are part of the Windows kernel (ntoskrnl.exe), which is the core of the Windows operating system. The prefix nt! indicates functions within the kernel.
IofCallDriver (line 06): A kernel function that forwards an I/O request packet (IRP) to a driver. The +0×55 indicates the offset within the function where the call occurred.
IopSynchronousServiceTail (line 07): A function that handles synchronous I/O operations. The +0×1d2 offset shows where in the function the operation occurred, indicating further processing of the IRP.
IopXxxControlFile (line 08): Likely a function that processes control operations (like IOCTL calls) on files. The +0xc82 is the offset where the call happened.
NtDeviceIoControlFile (line 09): A system service function that applications can call to execute device I/O control operations. The +0×56 offset indicates the point of execution within the function.
Line 0a (nt!KiSystemServiceCopyEnd): This is part of the system call dispatch mechanism, which is responsible for transitioning from user mode to kernel mode. +0×25 is the offset within this function.
Line 0b (ntdll!NtDeviceIoControlFile): This represents a call made from a user-mode application into the Windows Native API (NTDLL.dll) to perform a device I/O control operation. The +0×14 offset indicates the execution point within the function.
Line 0c (KERNELBASE!DeviceIoControl): This call originates from the KERNELBASE.dll, a Windows DLL that provides the base-level functionality for high-level APIs. The DeviceIoControl function is a wrapper that applications can use to send control codes to drivers. The +0×6b offset indicates where the function proceeds with the operation.
Line 0d (KERNEL32!DeviceIoControlImplementation): This is the implementation of the DeviceIoControl function in KERNEL32.dll, which is another layer of abstraction that eventually calls into the kernel-mode function to perform the operation. The +0×81 offset indicates the execution point within this implementation.
This stack trace illustrates how a device I/O control operation initiated by an application flows through various layers of the Windows operating system, from high-level APIs down to kernel-mode functions, to interact with a device driver. Each step in the process is crucial for understanding how the operating system processes I/O requests, handles system calls, and communicates with hardware.
Explain this stack trace fragment line by line:
00 msvcrt!vsnwprintf
01 wdscore!StringCchPrintfW
02 wdscore!CLogManager::LogA
03 wdscore!WdsSetupLogMessageA
04 cbscore!CBSWdsLog
05 cbscore!CCbsExecutionObject::AddPackage
06 cbscore!CCbsExecutionObject::AddPackage
07 cbscore!CCbsExecutionObject::AddPackage
08 cbscore!CCbsExecutionObject::RecallOrSupersedLowerVersion
09 cbscore!CCbsExecutionObject::ProcessMumServicing
0a cbscore!CCbsExecutionObject::AddPackage
0b cbscore!CCbsExecutionObject::Plan
0c cbscore!CCbsExecutionObject::GenerateExpressFileList
0d cbscore!CCbsSession::ActionListGenerateMissingFileList
0e cbscore!CCbsPublicSession::WritePackageFileList
0f RPCRT4!Invoke
10 RPCRT4!Ndr64StubWorker
11 RPCRT4!NdrStubCall3
12 combase!CStdStubBuffer_Invoke
13 RPCRT4!CStdStubBuffer_Invoke
14 combase!InvokeStubWithExceptionPolicyAndTracing::__l6::<lambda_ c9f3956a20c9da92a64affc24fdd69ec>::operator()
15 combase!ObjectMethodExceptionHandlingAction<<lambda_ c9f3956a20c9da92a64affc24fdd69ec> >
16 combase!InvokeStubWithExceptionPolicyAndTracing
17 combase!DefaultStubInvoke
18 combase!SyncServerCall::StubInvoke
19 combase!StubInvoke
1a combase!ServerCall::ContextInvoke
1b combase!CServerChannel::ContextInvoke
1c combase!DefaultInvokeInApartment
1d combase!ComInvokeWithLockAndIPID
1e combase!ThreadInvokeReturnHresult
1f combase!ThreadInvoke
20 RPCRT4!DispatchToStubInCNoAvrf
21 RPCRT4!RPC_INTERFACE::DispatchToStubWorker
22 RPCRT4!RPC_INTERFACE::DispatchToStubWithObject
23 RPCRT4!LRPC_SCALL::DispatchRequest
24 RPCRT4!LRPC_SCALL::HandleRequest
25 RPCRT4!LRPC_SASSOCIATION::HandleRequest
26 RPCRT4!LRPC_ADDRESS::HandleRequest
27 RPCRT4!LRPC_ADDRESS::ProcessIO
28 RPCRT4!LrpcIoComplete
29 ntdll!TppAlpcpExecuteCallback
2a ntdll!TppWorkerThread
2b KERNEL32!BaseThreadInitThunk
2c ntdll!RtlUserThreadStart
This stack trace seems to come from a Windows environment, and it illustrates the flow of a specific operation—likely a component-based servicing action (related to Windows Updates or system component management) that involves logging, package addition, and possibly dealing with an RPC (Remote Procedure Call) request. Let’s break down the stack trace line by line:
msvcrt!vsnwprintf: This function is part of the Microsoft Visual C Runtime Library. It’s a variant of snprintf that works with wide (Unicode) strings, used for formatted string operations.
wdscore!StringCchPrintfW: A function likely related to Windows Deployment Services (WDS) for secure string formatting into a buffer. StringCchPrintfW is a safer version of sprintf for wide strings.
wdscore!CLogManager::LogA: A method in the WDS core library for logging messages. This method suggests the operation involves ASCII string logging.
wdscore!WdsSetupLogMessageA: Another logging-related function in WDS, focused on setup log messages.
cbscore!CBSWdsLog: Indicates a function within the Component-Based Servicing (CBS) core library, specifically for logging in the context of WDS.
6-0a. cbscore!CCbsExecutionObject::AddPackage (lines 05 to 0a): Repeated calls to a method that adds a package to the CBS execution object. This could be part of an update or system component management operation.
cbscore!CCbsExecutionObject::RecallOrSupersedLowerVersion: A method that deals with recalling or superseding lower versions of a package or component.
cbscore!CCbsExecutionObject::ProcessMumServicing: A method likely involved in servicing manifest updates (MUM files), which are used in Windows servicing to describe updates.
cbscore!CCbsExecutionObject::Plan: Part of the planning phase in a CBS operation, where the system determines what actions to take with the packages.
cbscore!CCbsExecutionObject::GenerateExpressFileList: Generates a list of files for an express installation, which is a faster update method that only downloads necessary components.
cbscore!CCbsSession::ActionListGenerateMissingFileList: A method to generate a list of missing files based on the planned actions.
cbscore!CCbsPublicSession::WritePackageFileList: Writes out the list of files associated with the packages being serviced.
13-1e. RPCRT4 and combase (lines 0f to 1e): These lines involve the RPC runtime and COM base libraries, indicating that part of the operation was invoked over RPC, a mechanism that allows a program to execute code on another machine or process.
1f-2c. The stack trace concludes with system and thread initialization functions, like TppWorkerThread and BaseThreadInitThunk, which are part of the thread pool and thread startup routines in Windows. These functions are standard for threads executing in the Windows environment.
This trace is a deep dive into how Windows manages system components, specifically around updating or managing packages, and involves various subsystems like WDS, CBS, and RPC communications.
- Dmitry Vostokov @ DumpAnalysis.org + TraceAnalysis.org -