From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <systemtap-return-24403-listarch-systemtap=sources.redhat.com@sourceware.org>
Received: (qmail 123995 invoked by alias); 11 May 2016 01:24:12 -0000
Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm
Precedence: bulk
List-Id: <systemtap.sourceware.org>
List-Subscribe: <mailto:systemtap-subscribe@sourceware.org>
List-Post: <mailto:systemtap@sourceware.org>
List-Help: <mailto:systemtap-help@sourceware.org>, <http://sourceware.org/lists.html#faqs>
Sender: systemtap-owner@sourceware.org
Received: (qmail 123722 invoked by uid 48); 11 May 2016 01:23:59 -0000
From: "mysecondaccountabc at gmail dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug tapsets/20075] New: target_set_pid() returns False when execve() syscall is successful
Date: Wed, 11 May 2016 01:24:00 -0000
X-Bugzilla-Reason: AssignedTo
X-Bugzilla-Type: new
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: systemtap
X-Bugzilla-Component: tapsets
X-Bugzilla-Version: unspecified
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: mysecondaccountabc at gmail dot com
X-Bugzilla-Status: NEW
X-Bugzilla-Resolution:
X-Bugzilla-Priority: P2
X-Bugzilla-Assigned-To: systemtap at sourceware dot org
X-Bugzilla-Target-Milestone: ---
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields: bug_id short_desc product version bug_status bug_severity priority component assigned_to reporter target_milestone attachments.created
Message-ID: <bug-20075-6586@http.sourceware.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
X-Bugzilla-URL: http://sourceware.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2016-q2/txt/msg00094.txt.bz2

https://sourceware.org/bugzilla/show_bug.cgi?id=3D20075

            Bug ID: 20075
           Summary: target_set_pid() returns False when execve() syscall
                    is successful
           Product: systemtap
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: tapsets
          Assignee: systemtap at sourceware dot org
          Reporter: mysecondaccountabc at gmail dot com
  Target Milestone: ---

Created attachment 9250
  --> https://sourceware.org/bugzilla/attachment.cgi?id=3D9250&action=3Dedit
Script to show the issue

When execve() is called and it returns without error, for some reason a cal=
l to
target_set_pid(pid()) in this context returns "False", wrongly indicating t=
hat
the pid doesn't descend from the target process. It causes that syscall be
discarded from the syscall trace.

I'm using a slightly modified version of "strace.stp" to show the issue, see
the attachment.

sudo stap my_strace.stp -w -c "sh -c /bin/ls"=20

=3D=3D=3D=3D
...

||OK_CALL 3||: target_set_pid(12701):1 target:12701
||OK_RETURN 3||: target_set_pid(12701):1 target:12701
Wed May 11 00:49:14 2016.822339 rt_sigprocmask(SIG_SETMASK, [EMPTY], 0x0, 8=
) =3D
0

||OK_CALL 3||: target_set_pid(12701):1 target:12701
||OK_RETURN 3||: target_set_pid(12701):1 target:12701
Wed May 11 00:49:14 2016.822364 execve("/usr/local/sbin/sh", ["sh", "-c",
"/bin/ls"], [/* 18 vars */]) =3D -2 (ENOENT)

...

||OK_CALL 3||: target_set_pid(12701):1 target:12701
||FILTERED_RETURN 2||: target_set_pid(12701):0
>>FILTERED_RETURN<<: sh[12701] execve("/bin/sh", ["sh", "-c", "/bin/ls"], [=
/* 18 vars */]) =3D 0

...=20
=3D=3D=3D=3D

As you can see above in the last three lines, when the successful execve is
called, the target_set_pid(pid()) call in the nd_syscall.*.return probe ret=
urns
False "target_set_pid(12701):0", causing the syscall to be dropped.

--=20
You are receiving this mail because:
You are the assignee for the bug.