Direct download:
Download the tool executable that matches your platform:
Platform
To use dotnet-dump on an x86 app, you need a corresponding x86 version of the tool.
Synopsis
dotnet-dump [-h|--help] [--version] <command>
Description
The dotnet-dump global tool is a way to collect and analyze dumps on Windows, Linux, and macOS without any native debugger involved. This tool is important on platforms like Alpine Linux where a fully working lldb isn't available. The dotnet-dump tool allows you to run SOS commands to analyze crashes and the garbage collector (GC), but it isn't a native debugger so things like displaying native stack frames aren't supported.
Options
--version
Displays the version of the dotnet-dump utility.
-h|--help
Shows command-line help.
Commands
Command
Captures a dump from a process.
Synopsis
dotnet-dump collect [-h|--help] [-p|--process-id] [-n|--name] [--type] [-o|--output] [--diag] [--crashreport]
Options
-h|--help
Shows command-line help.
-p|--process-id <PID>
Specifies the process ID number to collect a dump from.
-n|--name <name>
Specifies the name of the process to collect a dump from.
--type <Full|Heap|Mini>
Specifies the dump type, which determines the kinds of information that are collected from the process. There are three types:
Full - The largest dump containing all memory including the module images.
Heap - A large and relatively comprehensive dump containing module lists, thread lists, all stacks, exception information, handle information, and all memory except for mapped images.
Mini - A small dump containing module lists, thread lists, exception information, and all stacks.
If not specified, Full is the default.
-o|--output <output_dump_path>
The full path and file name where the collected dump should be written. Ensure that the user under which the dotnet process is running has write permissions to the specified directory.
If not specified:
Defaults to .\dump_YYYYMMDD_HHMMSS.dmp on Windows.
Defaults to ./core_YYYYMMDD_HHMMSS on Linux and macOS.
YYYYMMDD is Year/Month/Day and HHMMSS is Hour/Minute/Second.
--diag
Enables dump collection diagnostic logging.
--crashreport
Enables crash report generation.
On Linux and macOS, this command expects the target application and dotnet-dump to share the same TMPDIR environment variable. Otherwise, the command will time out.
To collect a dump using dotnet-dump, it needs to be run as the same user as the user running target process or as root. Otherwise, the tool will fail to establish a connection with the target process.
dotnet-dump analyze
Starts an interactive shell to explore a dump. The shell accepts various SOS commands.
Synopsis
dotnet-dump analyze <dump_path> [-h|--help] [-c|--command]
Arguments
<dump_path>
Specifies the path to the dump file to analyze.
Options
-c|--command <debug_command>
Specifies the command to run in the shell on start.
Analyze SOS commands
Command
Function
analyzeoom
Displays the info of the last OOM that occurred on an allocation request to the GC heap.
clrmodules
Lists the managed modules in the process.
clrstack
Provides a stack trace of managed code only.
clrthreads
Lists the managed threads that are running.
Displays an annotated disassembly of a managed method.
d or readmemory
Dumps memory contents.
dbgout
Enables/disables (-off) internal SOS logging.
Displays all managed objects found within the bounds of the current stack.
dumpalc
Displays details about a collectible AssemblyLoadContext to which the specified object is loaded.
dumparray
Displays details about a managed array.
dumpasync
Displays info about async state machines on the garbage-collected heap.
dumpassembly
Displays details about an assembly.
dumpclass
Displays information about the EEClass structure at the specified address.
dumpconcurrentdictionary
Displays concurrent dictionary content.
dumpconcurrentqueue
Displays concurrent queue content.
dumpdelegate
Displays information about a delegate.
dumpdomain
Displays information about the all assemblies within all the AppDomains or the specified one.
dumpgcdata
Displays information about the GC data.
dumpgen
Displays heap content for the specified generation.
dumpheap
Displays info about the garbage-collected heap and collection statistics about objects.
dumpil
Displays the Microsoft intermediate language (MSIL) that's associated with a managed method.
dumplog
Writes the contents of an in-memory stress log to the specified file.
dumpmd
Displays information about the MethodDesc structure at the specified address.
dumpmodule
Displays information about the module at the specified address.
dumpmt
Displays information about the method table at the specified address.
dumpobj
Displays info the object at the specified address.
dumpruntimetypes
Finds all System.RuntimeType objects in the GC heap and prints the type name and MethodTable they refer too.
dumpsig
Dumps the signature of a method or field specified by <sigaddr> <moduleaddr>.
dumpsigelem
Dumps a single element of a signature object.
dumpstack
Displays a native and managed stack trace.
dumpstackobjects
Displays all managed objects found within the bounds of the current stack.
dumpvc
Displays info about the fields of a value class.
eeheap
Displays info about process memory consumed by internal runtime data structures.
eestack
Runs dumpstack on all threads in the process.
eeversion
Displays information about the runtime and SOS versions.
ehinfo
Displays the exception handling blocks in a JIT-ed method.
exit or quit
Exits interactive mode.
finalizequeue
Displays all objects registered for finalization.
findappdomain
Attempts to resolve the AppDomain of a GC object.
gchandles
Displays statistics about garbage collector handles in the process.
gcheapstat
Displays statistics about garbage collector.
gcinfo
Displays the JIT GC encoding for a method.
gcroot
Displays info about references (or roots) to the object at the specified address.
gcwhere
Displays the location in the GC heap of the specified address.
histclear
Releases any resources used by the family of Hist commands.
histinit
Initializes the SOS structures from the stress log saved in the debuggee.
histobj
Examines all stress log relocation records and displays the chain of garbage collection relocations that may have led to the address passed in as an argument.
histobjfind
Displays all the log entries that reference the object at the specified address.
histroot
Displays information related to both promotions and relocations of the specified root.
histstats
Displays stress log stats.
ip2md
Displays the MethodDesc structure at the specified address in code that has been JIT-compiled.
listnearobj
Displays the object preceding and succeeding the specified address.
logopen
Enables console file logging.
logclose
Disables console file logging.
logging
Enables/disables internal SOS logging.
lm or modules
Displays the native modules in the process.
name2ee
Displays the MethodTable and EEClass structures for the specified type or method in the specified module.
objsize
Displays the size of the specified object.
parallelstacks
Displays the merged threads stack similarly to the Visual Studio 'Parallel Stacks' panel.
pathto
Displays the GC path from <root> to <target>.
pe or printexception
Displays and formats fields of any object derived from the Exception class at the specified address.
r or registers
Displays the thread's registers.
runtimes
Lists the runtimes in the target or changes the default runtime.
setclrpath
Sets the path to load coreclr dac/dbi files using setclrpath <path>.
setsymbolserver
Enables the symbol server support.
Executes various coreclr debugging commands. Use the syntax sos <command-name> <args>. For more information, see 'soshelp'.
soshelp or help
Displays all available commands.
soshelp <command> or help <command>
Displays the specified command.
syncblk
Displays the SyncBlock holder info.
taskstate
Displays a Task state in a human readable format.
threadpool
Displays info about the runtime thread pool.
threadpoolqueue
Displays queued thread pool work items.
threadstate
Pretty prints the meaning of a threads state.
threads <threadid> or setthread <threadid>
Sets or displays the current thread ID for the SOS commands.
timerinfo
Displays information about running timers.
token2ee
Displays the MethodTable structure and MethodDesc structure for the specified token and module.
traverseheap
Writes out heap information to a file in a format understood by the CLR Profiler.
verifyheap
Checks the GC heap for signs of corruption.
verifyobj
Checks the object that is passed as an argument for signs of corruption.
dotnet-dump ps
Lists the dotnet processes that dumps can be collected from.
dotnet-dump version 6.0.320703 and later versions also display the command-line arguments that each process was started with, if available.
Synopsis
dotnet-dump ps [-h|--help]
Example
Suppose you start a long-running app using the command dotnet run --configuration Release. In another window, you run the dotnet-dump ps command. The output you'll see is as follows. The command-line arguments, if any, are shown in dotnet-dump version 6.0.320703 and later.
> dotnet-dump ps
21932 dotnet C:\Program Files\dotnet\dotnet.exe run --configuration Release
36656 dotnet C:\Program Files\dotnet\dotnet.exe
Using dotnet-dump
The first step is to collect a dump. This step can be skipped if a core dump has already been generated. The operating system or the .NET Core runtime's built-in dump generation feature can each create core dumps.
$ dotnet-dump collect --process-id 1902
Writing minidump to file ./core_20190226_135837
Written 98983936 bytes (24166 pages) to core file
Complete
Now analyze the core dump with the analyze command:
$ dotnet-dump analyze ./core_20190226_135850
Loading core dump: ./core_20190226_135850
Ready to process analysis commands. Type 'help' to list available commands or 'help [command]' to get detailed help on a command.
Type 'quit' or 'exit' to exit the session.
This action brings up an interactive session that accepts commands like:
> clrstack
OS Thread Id: 0x573d (0)
Child SP IP Call Site
00007FFD28B42C58 00007fb22c1a8ed9 [HelperMethodFrame_PROTECTOBJ: 00007ffd28b42c58] System.RuntimeMethodHandle.InvokeMethod(System.Object, System.Object[], System.Signature, Boolean, Boolean)
00007FFD28B42DD0 00007FB1B1334F67 System.Reflection.RuntimeMethodInfo.Invoke(System.Object, System.Reflection.BindingFlags, System.Reflection.Binder, System.Object[], System.Globalization.CultureInfo) [/root/coreclr/src/mscorlib/src/System/Reflection/RuntimeMethodInfo.cs @ 472]
00007FFD28B42E20 00007FB1B18D33ED SymbolTestApp.Program.Foo4(System.String) [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 54]
00007FFD28B42ED0 00007FB1B18D2FC4 SymbolTestApp.Program.Foo2(Int32, System.String) [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 29]
00007FFD28B42F00 00007FB1B18D2F5A SymbolTestApp.Program.Foo1(Int32, System.String) [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 24]
00007FFD28B42F30 00007FB1B18D168E SymbolTestApp.Program.Main(System.String[]) [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 19]
00007FFD28B43210 00007fb22aa9cedf [GCFrame: 00007ffd28b43210]
00007FFD28B43610 00007fb22aa9cedf [GCFrame: 00007ffd28b43610]
To see an unhandled exception that killed your app:
> pe -lines
Exception object: 00007fb18c038590
Exception type: System.Reflection.TargetInvocationException
Message: Exception has been thrown by the target of an invocation.
InnerException: System.Exception, Use !PrintException 00007FB18C038368 to see more.
StackTrace (generated):
SP IP Function
00007FFD28B42DD0 0000000000000000 System.Private.CoreLib.dll!System.RuntimeMethodHandle.InvokeMethod(System.Object, System.Object[], System.Signature, Boolean, Boolean)
00007FFD28B42DD0 00007FB1B1334F67 System.Private.CoreLib.dll!System.Reflection.RuntimeMethodInfo.Invoke(System.Object, System.Reflection.BindingFlags, System.Reflection.Binder, System.Object[], System.Globalization.CultureInfo)+0xa7 [/root/coreclr/src/mscorlib/src/System/Reflection/RuntimeMethodInfo.cs @ 472]
00007FFD28B42E20 00007FB1B18D33ED SymbolTestApp.dll!SymbolTestApp.Program.Foo4(System.String)+0x15d [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 54]
00007FFD28B42ED0 00007FB1B18D2FC4 SymbolTestApp.dll!SymbolTestApp.Program.Foo2(Int32, System.String)+0x34 [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 29]
00007FFD28B42F00 00007FB1B18D2F5A SymbolTestApp.dll!SymbolTestApp.Program.Foo1(Int32, System.String)+0x3a [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 24]
00007FFD28B42F30 00007FB1B18D168E SymbolTestApp.dll!SymbolTestApp.Program.Main(System.String[])+0x6e [/home/mikem/builds/SymbolTestApp/SymbolTestApp/SymbolTestApp.cs @ 19]
StackTraceString: <none>
HResult: 80131604
Troubleshooting dump collection issues
Dump collection requires the process to be able to call ptrace. If you are facing issues collecting dumps, the environment you are running on may be configured to restrict such calls. See our Dumps: FAQ for troubleshooting tips and potential solutions to common issues.
See also
Collecting and analyzing memory dumps blog
Heap analysis tool (dotnet-gcdump)
