[Bug uprobes/16662] New: return probe breaks functionality of rsync

[Bug uprobes/16662] New: return probe breaks functionality of rsync

[c.bezemer at tudelft dot nl]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

            Bug ID: 16662
           Summary: return probe breaks functionality of rsync
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: uprobes
          Assignee: systemtap at sourceware dot org
          Reporter: c.bezemer at tudelft dot nl

When I try to run the following probe:

    probe
process("/home/jenkins/workspace/test_systemtap_rsync_unittests/rsync/rsync").function("*")
?
    {
            printf("IN %s\n", probefunc());
    }

    probe
process("/home/jenkins/workspace/test_systemtap_rsync_unittests/rsync/rsync").function("*").return
    {
            printf("OUT %s\n", probefunc());
    }

The functionality of rsync breaks if the return probe is enabled. When the
return probe is disabled, there is no problem.

dmesg contains '[3021183.636783] rsync[10263]: segfault at 7fffffffe000 ip
00007fffffffe000 sp 00007fff32f44130 error 14'

Kernel version: kernel 3.12-trunk-amd64
Systemtap version: 2.4/0.157

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[Bug uprobes/16662] return probe breaks functionality of rsync

[c.bezemer at tudelft dot nl]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

--- Comment #1 from c.bezemer at tudelft dot nl <c.bezemer at tudelft dot nl> ---
I noticed similar behaviour for the git unit test as well:

git clone https://github.com/git/git.git
cd git
make

'make test' without a probe runs fine.

Now when I run 'make test'  with the following probe:

probe
process("/home/jenkins/workspace/test_systemtap_git_unittests/git/git").function("*")
{
        printf("in %s\n", probefunc());
}

The output of the first unit test is:
*** t0000-basic.sh ***
error: cannot run git init -- have you built things yet?

and dmesg shows:
[3107980.105350] traps: git-init[3268] general protection ip:7fffffffe080
sp:7fff53de4390 error:0

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[Bug uprobes/16662] return probe breaks functionality of rsync

[jlebon at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

Jonathan Lebon <jlebon at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jlebon at redhat dot com

--- Comment #2 from Jonathan Lebon <jlebon at redhat dot com> ---
(In reply to c.bezemer@tudelft.nl from comment #0)
> When I try to run the following probe:
> 
>     probe
> process("/home/jenkins/workspace/test_systemtap_rsync_unittests/rsync/
> rsync").function("*") ?
>     {
>             printf("IN %s\n", probefunc());
>     }
>      
>     probe
> process("/home/jenkins/workspace/test_systemtap_rsync_unittests/rsync/
> rsync").function("*").return
>     {
>             printf("OUT %s\n", probefunc());
>     }
> 
> The functionality of rsync breaks if the return probe is enabled. When the
> return probe is disabled, there is no problem.
> 
> dmesg contains '[3021183.636783] rsync[10263]: segfault at 7fffffffe000 ip
> 00007fffffffe000 sp 00007fff32f44130 error 14'
> 
> Kernel version: kernel 3.12-trunk-amd64
> Systemtap version: 2.4/0.157

Thanks for the report. More specifically, this occurs when placing a uretprobe
on the _start function.

Fedora BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1073605
RHEL7 BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1073627

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[Bug uprobes/16662] return probe breaks functionality of rsync

[jlebon at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

--- Comment #3 from Jonathan Lebon <jlebon at redhat dot com> ---
(In reply to c.bezemer@tudelft.nl from comment #1)
> I noticed similar behaviour for the git unit test as well:
> 
> git clone https://github.com/git/git.git
> cd git
> make
> 
> 'make test' without a probe runs fine.
> 
> Now when I run 'make test'  with the following probe:
> 
> probe
> process("/home/jenkins/workspace/test_systemtap_git_unittests/git/git").
> function("*")
> {
>         printf("in %s\n", probefunc());
> }
> 
> The output of the first unit test is:
> *** t0000-basic.sh ***
> error: cannot run git init -- have you built things yet?
> 
> and dmesg shows:
> [3107980.105350] traps: git-init[3268] general protection ip:7fffffffe080
> sp:7fff53de4390 error:0

This seems like an issue with SystemTap. It occurs when probing the
create_object_directory() function, which causes 'git init' to get SIGSEGV. It
occurs with the Fedora packaged git as well:

$ uname -r
3.13.5-101.fc19.x86_64
$ stap -V
Systemtap translator/driver (version 2.5/0.156, commit
release-2.4-313-g7f991c982def)
Copyright (C) 2005-2014 Red Hat, Inc. and others
This is free software; see the source for copying conditions.
enabled features: AVAHI LIBRPM LIBSQLITE3 NSS BOOST_SHARED_PTR
TR1_UNORDERED_MAP NLS DYNINST JAVA LIBVIRT LIBXML2
$ git --version
git version 1.8.3.1
$ git init
Reinitialized existing Git repository in /tmp/.git/
$ stap -e 'probe process("/usr/bin/git").function("main") { next }' -c 'git
init'
Reinitialized existing Git repository in /tmp/.git/
$ stap -e 'probe process("/usr/bin/git").function("create_object_directory") {
next }' -c 'git init'
WARNING: Child process exited with signal 11 (Segmentation fault)
WARNING: /home/yyz/jlebon/codebase/systemtap/install/bin/staprun exited with
status: 1
Pass 5: run failed.  [man error::pass5]
$

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[Bug uprobes/16662] return probe breaks functionality of rsync

[jlebon at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

--- Comment #4 from Jonathan Lebon <jlebon at redhat dot com> ---
(In reply to Jonathan Lebon from comment #3)
> This seems like an issue with SystemTap. It occurs when probing the
> create_object_directory() function, which causes 'git init' to get SIGSEGV.

Looks like it might be a kernel issue after all. Using perf to place the probe
also causes the SIGSEGV. I updated the kernel BZs with the information:

Fedora: https://bugzilla.redhat.com/show_bug.cgi?id=1073605#c1
RHEL7: https://bugzilla.redhat.com/show_bug.cgi?id=1073627#c2

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[Bug uprobes/16662] return probe breaks functionality of rsync

[fche at redhat dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=16662

Frank Ch. Eigler <fche at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |fche at redhat dot com
         Resolution|---                         |DUPLICATE

--- Comment #5 from Frank Ch. Eigler <fche at redhat dot com> ---
kernel uprobes bug indicated, already tracked elsewhere

*** This bug has been marked as a duplicate of bug 15972 ***

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