DebuginfoFS
Summary
A read-only, internet-mountable filesystem that provides debuginfo (for use with 
gdb
a client service to mount the debuginfo filesystem when needed.
Owner
- Name: Will Woods
- email: wwoods@redhat.com
Current status
- Targeted release: Fedora 11
- Last updated: January 28, 2009
- Percentage of completion: 30%
Detailed Description
When a program crashes or is otherwise misbehaving, one of the most helpful things to put in a bug report is a traceback of the offending process, gathered by using
debuginfo-install can be used to install the needed debuginfo packages, but this takes a long time (2-5 minutes) and 95% of the installed data is unused.
This Feature will provide scripts and tools to provide a WebDAV filesystem containing all the debuginfo needed for everything in Fedora, and a service to allow users (or automatic crash-reporting processes - like Features/CrashCatcher) to mount the filesystem when needed.
Benefit to Fedora
By simplifying the process of getting debugging info, we can improve the quality of bug reports, which should make it easier (and faster) to get bugs fixed.
Scope
There will be two main parts to this feature:
- A
debuginfofs-serverpackage, which provides- A
debuginfofs-serverservice, - Configuration files to specify which distributions (version/arch) to support, and
- Some documentation on setting up / maintaining the server.
- A
- A
debuginfofspackage, which provides- A
debuginfofsservice, - Configuration files to specify the location of the server
- A
We should also provide a public debuginfofs server for Fedora users, and pre-configure the service to use that.
How To Test
1. Prepare a debuginfo server
- Instructions / public instance coming soon
2. Install debuginfofs
- git repo / packages coming soon
3. Mount debuginfofs
sudo service debuginfofs start
4. Crash a program in gdb
[wwoods@metroid debuginfofs]$ gdb $(which sleep) GNU gdb Fedora (6.8-29.fc10) Copyright (C) 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "i386-redhat-linux-gnu"... (gdb) set args 999 (gdb) run Starting program: /bin/sleep 999 [Hit Ctrl-C] Program received signal SIGINT, Interrupt. __kernel_vsyscall () at arch/x86/vdso/vdso32/int80.S:16 16 arch/x86/vdso/vdso32/int80.S: No such file or directory. in arch/x86/vdso/vdso32/int80.S Current language: auto; currently asm (gdb) bt #0 __kernel_vsyscall () at arch/x86/vdso/vdso32/int80.S:16 #1 0x008ac430 in __nanosleep_nocancel () from /lib/libc.so.6 #2 0x0804abd3 in xnanosleep (seconds=999) at xnanosleep.c:112 #3 0x080490f6 in main (argc=2, argv=0xbffff514) at sleep.c:150 (gdb)
If everything is working as expected, you will see the function/file names, as above.
User Experience
Getting debuginfo to get a backtrace for a bug report will become much, much easier (and faster), but the process will change slightly.
Dependencies
- A public debuginfofs server will require somewhere around 40GB of disk per Fedora version/arch - a total of 500GB for Fedora (8,9,10) * (i386,x86_64,ppc).
- Some further work could be done to drastically reduce the amount of disk space needed by only unpacking debuginfo when it is needed - this may be required if the Fedora infrastructure can't spare that much disk space.
- If we need access to the source files as well as the debugging symbols, there will need to be an additional layer on the client-side to find the source files and put them in a place where
gdbcan find them.
Contingency Plan
None needed - things stay as they are.
Documentation
The gdb info pages and Releases/FeatureBuildId give some background on the Build-Id feature that makes this possible.
Release Notes
There is a new debuginfofs service, which provides debuginfo for all Fedora packages over the Internet.