Bug 442330 - [patch] x86_64 VDSO has no debug info
Summary: [patch] x86_64 VDSO has no debug info
Alias: None
Product: Fedora
Classification: Fedora
Component: kernel
Version: 9
Hardware: x86_64
OS: Linux
Target Milestone: ---
Assignee: Kernel Maintainer List
QA Contact: Fedora Extras Quality Assurance
Depends On:
TreeView+ depends on / blocked
Reported: 2008-04-14 13:27 UTC by Jan Kratochvil
Modified: 2009-07-14 15:44 UTC (History)
1 user (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2009-07-14 15:44:31 UTC

Attachments (Terms of Use)
Fix. (536 bytes, patch)
2008-04-14 13:27 UTC, Jan Kratochvil
no flags Details | Diff

Description Jan Kratochvil 2008-04-14 13:27:24 UTC
Description of problem:
With recent Rawhide kernels Fedora GDB started to complain on VDSO:
The separate debug info file has no debug info

Version-Release number of selected component (if applicable):
kernel-debuginfo-2.6.25-0.172.rc7.git4.fc9.x86_64 (broken)
kernel-debuginfo-2.6.25-0.218.rc8.git7.fc9.x86_64 (broken)
(but F-8 kernel-debuginfo- is still OK)
gdb-6.6-45.fc8.x86_64 OR gdb-6.8-1.fc9.x86_64

How reproducible:

Steps to Reproduce:
1. yum install kernel-debuginfo
2. gdb -q /bin/true

Actual results:
Using host libthread_db library "/lib64/libthread_db.so.1".
(gdb) run
Starting program: /bin/true 
The separate debug info file has no debug info

Program exited normally.
(gdb) q

Expected results:
Using host libthread_db library "/lib64/libthread_db.so.1".
(gdb) run
Starting program: /bin/true 

Program exited normally.
(gdb) q

Additional info:
In fact it makes no difference on i686 where it is used for the backtraces and I
admit I did not check how the VDSO is currently used on x86_64.

Still the fix is IMO clear.

Test build was prepared at:

/usr/lib/debug/lib/modules/*/vdso/vdso.so.debug has more symbols in .symtab than
/lib/modules/*/vdso/vdso.so but none of them has .debug_info while VDSO was
assembled from .c files.

i686 does not seem to have VDSO from .c files so it makes no difference there.

Comment 1 Jan Kratochvil 2008-04-14 13:27:24 UTC
Created attachment 302334 [details]

Comment 2 Roland McGrath 2008-04-14 19:40:34 UTC
Similar fix posted upstream: http://marc.info/?l=linux-kernel&m=120820101915033&w=4

The x86_64 vDSO is used far less than the 32-bit x86 vDSO (it's not necessary
for backtraces from syscalls or signals, for example).  So I think the only
trouble for most users is the pesky message from gdb.  If that is enough of a
concern, we can put the patch in rawhide/f9.  If not, just close as UPSTREAM.

Comment 3 Jan Kratochvil 2008-04-14 20:11:15 UTC
(In reply to comment #2)
> So I think the only trouble for most users is the pesky message from gdb.

It is a message from the so-far Fedora-only build-id files-locating patch.

In fact there should be IMO a sanity check in `find-debuginfo.sh' that any
.debug file has some `.debug_info' section (at least with just

Comment 4 Roland McGrath 2008-04-14 20:23:33 UTC
They're still valid if they just have a symtab and no DWARF, technically.
And if that's not the case, the file output won't have "not stripped" and so
they won't be processed.

Still, I think a sanity check of some sort, and even just a warning about no
DWARF, might be reasonable.

Comment 5 Chuck Ebbert 2008-04-29 19:06:38 UTC
Patch is merged in 2.6.26-rc

commit 8705a49c35be088a50b8d5fc5e1aa24d6711fd5b
x86 vDSO: compile with -g, 64-bit

Do we want this in F9?

Comment 6 Jan Kratochvil 2008-04-29 20:10:58 UTC
Yes, it would be nice in F9 just because of that annoying GDB warning, thanks:
warning: "/usr/lib/debug/lib/modules/2.6.25-8.fc9.x86_64/vdso/vdso.so.debug":
The separate debug info file has no debug info
I could patch it in GDB but probably a kernel fix is better.

Comment 7 Bug Zapper 2008-05-14 09:23:44 UTC
Changing version to '9' as part of upcoming Fedora 9 GA.
More information and reason for this action is here:

Comment 8 Bug Zapper 2009-06-10 00:10:00 UTC
This message is a reminder that Fedora 9 is nearing its end of life.
Approximately 30 (thirty) days from now Fedora will stop maintaining
and issuing updates for Fedora 9.  It is Fedora's policy to close all
bug reports from releases that are no longer maintained.  At that time
this bug will be closed as WONTFIX if it remains open with a Fedora 
'version' of '9'.

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Comment 9 Bug Zapper 2009-07-14 15:44:31 UTC
Fedora 9 changed to end-of-life (EOL) status on 2009-07-10. Fedora 9 is 
no longer maintained, which means that it will not receive any further 
security or bug fix updates. As a result we are closing this bug.

If you can reproduce this bug against a currently maintained version of 
Fedora please feel free to reopen this bug against that version.

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