Bug 21532 - When the app's standard input has been redirected, lldb does not quit after printing native stack trace
Summary: When the app's standard input has been redirected, lldb does not quit after p...
Status: RESOLVED FIXED
Alias: None
Product: Runtime
Classification: Mono
Component: Debugger ()
Version: unspecified
Hardware: PC Mac OS
: --- normal
Target Milestone: ---
Assignee: Zoltan Varga
URL:
Depends on:
Blocks:
 
Reported: 2014-07-23 01:01 UTC by Brendan Zagaeski (Xamarin Team, assistant)
Modified: 2015-05-15 19:50 UTC (History)
2 users (show)

Tags:
Is this bug a regression?: ---
Last known good build:


Attachments
Example app and lldb output (5.98 KB, text/plain)
2014-07-23 01:01 UTC, Brendan Zagaeski (Xamarin Team, assistant)
Details


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Status:
RESOLVED FIXED

Description Brendan Zagaeski (Xamarin Team, assistant) 2014-07-23 01:01:23 UTC
Created attachment 7465 [details]
Example app and lldb output

When an app is being debugged via the soft debugger and has redirected standard input, if it crashes in native code, lldb will print a native stack trace and then never quit.

This problem happens for Xamarin.Mac apps, and also console C# apps when "Run on external console" is switched OFF.


This is a follow-up to https://bugzilla.xamarin.com/show_bug.cgi?id=19732.


## Steps to reproduce (Xamarin Studio)

1. Build `test.exe` from bug #19732.

2. Launch Xamarin Studio.

3. Choose "Run -> Debug Application", and select `test.exe`.


## Steps to reproduce (sdb)

1. Build `test.exe` from bug #19732.

2. Run `sdb`, and then run "listen 127.0.0.1 57664" at the `sdb` prompt.

4. In a separate terminal, run `test.exe`, connecting it to `sdb`:
> echo "foo" | /Library/Frameworks/Mono.framework/Versions/3.6.0/bin/mono --debug --debugger-agent=transport=dt_socket,address=127.0.0.1:57664 test.exe

5. Once the `lldb` output from the app ends, type Ctrl-C in the `sdb` window.

6. Run "kill" at the `sdb` prompt, and then "quit".


## Result
Example app output (including lldb output) is attached.


### /var/log/system.log

> 7/22/14 11:27:35.424 PM com.apple.debugserver-310.2[64033]: debugserver-310.2 for x86_64.
> 7/22/14 11:27:35.425 PM com.apple.debugserver-310.2[64033]: Got a connection, waiting for process information for launching or attaching.
> 7/22/14 11:27:35.707 PM com.apple.debugserver-310.2[64033]: Attach succeeded, ready to debug.
> 7/22/14 11:27:36.068 PM com.apple.debugserver-310.2[64033]: 1 +0.000000 sec [fa21/0303]: error: ::ptrace (request = PT_THUPDATE, pid = 0xfa1f, tid = 0x1a03, signal = -1) err = Invalid argument (0x00000016)
> 7/22/14 11:27:36.068 PM com.apple.debugserver-310.2[64033]: Exiting.


### ps ajx | grep lldb | grep Xcode

> username      66915     1 66913      0    0 S    s002    0:00.40 /Applications/Xcode.app/Contents/Developer/usr/bin/lldb --source /tmp/mono-gdb-commands.uyO9Ko


## Version Information
Xamarin Studio 5.2 (build 384)
Mono 3.6.0 ((no/f540f8a)
sdb 1.4.5316.43108 (1b62183)
Comment 1 Brendan Zagaeski (Xamarin Team, assistant) 2014-07-23 01:05:02 UTC
## Xcode and Mac version information
Xcode 5.1 (5084) Build 5B130a
OS X 10.9.4
Comment 2 Brendan Zagaeski (Xamarin Team, assistant) 2014-07-23 01:31:22 UTC
Ah. Of course now I notice that the soft debugger isn't actually required.


## Simpler steps to reproduce

1. Build `test.exe` from bug #19732.

2. Run `test.exe` with redirected standard input:
echo "foo" | mono test.exe

3. After the app outputs the "(lldb) quit" line, type Ctrl-C.


`lldb` is still running after these steps.
Comment 3 Zoltan Varga 2014-07-29 18:39:09 UTC
The current lldb version is beta quality, it has a ton of problems. Until those are solved, it might be better to use the old gdb from xcode 4.
Comment 4 Zoltan Varga 2015-05-15 19:50:34 UTC
Disabled spawning lldb for the time being.