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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:#1F497D'>Valgrind meet containers.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Containers meet valgrind.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I’ve found what lxc doesn’t like when running valgrind.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>The lxc_start() checks to see if there are extra file descriptors open and won’t call __lxc_start().<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: inherited fd 1024 on /home/vallevand/trunk_s4m/s4m-appliance/src/vdrd/vgVdrTest<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: inherited fd 1025 on /tmp/valgrind_proc_24989_cmdline_4fbfb9a5 (deleted)VdrTest<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: inherited fd 1026 on /dev/pts/1ind_proc_24989_cmdline_4fbfb9a5 (deleted)VdrTest<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: inherited fd 1027 on pipe:[768863]_proc_24989_cmdline_4fbfb9a5 (deleted)VdrTest<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: inherited fd 1028 on pipe:[768863]_proc_24989_cmdline_4fbfb9a5 (deleted)VdrTest<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Vdr1 is the name of my container. All those open files in the child process are related to valgrind.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>If I call __lxc_start() rather than lxc_start(), I see this:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: sync wake failure : Broken pipe<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>vdr1: failed to spawn 'vdr1'<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>And, just before that there is some complaining from valgrind:<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086== Syscall param clone(child_tidptr) contains uninitialised byte(s)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086== at 0x56622E1: clone (clone.S:84)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086== by 0x4E3BD38: __lxc_start (in /usr/lib/lxc/liblxc.so.0.7.5)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086== by 0x4014C9: vgVdrStartClone (vgVdrTest.c:88)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086== by 0x400F0A: main (vgVdrTest.c:337)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==25086==<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Syscall param wait4(status) points to unaddressable byte(s)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== at 0x53607C4: wait (wait.c:32)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== by 0x4E3A400: ??? (in /usr/lib/lxc/liblxc.so.0.7.5)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== by 0x566231C: clone (clone.S:112)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Address 0xffffffffffffffd4 is not stack'd, malloc'd or (recently) free'd<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1==<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Invalid write of size 4<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== at 0x4E3A4FF: ??? (in /usr/lib/lxc/liblxc.so.0.7.5)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== by 0x566231C: clone (clone.S:112)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Address 0xffffffffffffffc0 is not stack'd, malloc'd or (recently) free'd<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1==<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1==<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Process terminating with default action of signal 11 (SIGSEGV)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== Access not within mapped region at address 0xFFFFFFFFFFFFFFC0<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== at 0x4E3A4FF: ??? (in /usr/lib/lxc/liblxc.so.0.7.5)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>==1== by 0x566231C: clone (clone.S:112)<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Our program is designed to close all open file descriptors in the child process before calling lxc_start(). That code can try to close all file descriptors to make sure something doesn’t sneak through. However, closing the file descriptors associated with valgrind does not work. I get errno=0 Bad File Descriptor. Valgrind really has them held open. I am running as root in all these tests.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>I’ve also reproduced the problem using the ‘lxc-‘ programs. If you do something like ‘lxc-create –n XXX’ and then something like ‘valgrind lxc-start –n XXX -- ls’ you’ll see it. Well, the flavor of the error with open file descriptors.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>My hopes aren’t high, but any ideas are very welcome.<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><div><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Regards.</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'> <br></span><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>Mark K Vallevand</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'> <o:p></o:p></span></p></div><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:#1F497D'>"If there are no dogs in Heaven, then when I die I want to go where they went."<br>-Will Rogers<br></span><span style='font-size:12.0pt;font-family:"Times New Roman","serif";color:#1F497D'><br></span><span style='font-size:10.0pt;font-family:"Times New Roman","serif";color:#1F497D'>THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.</span><span style='color:#1F497D'><o:p></o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> lxc-users [mailto:lxc-users-bounces@lists.linuxcontainers.org] <b>On Behalf Of </b>Vallevand, Mark K<br><b>Sent:</b> Thursday, September 25, 2014 09:19 AM<br><b>To:</b> lxc-users@lists.linuxcontainers.org<br><b>Subject:</b> [lxc-users] Using valgrind with lxc<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>In our program, we do a fork() and in the child process the lxc library is called to start a program in a container using lxc_start().<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>We don’t care about valgrind in the child process. You can disable valgrind messages from child processes, but you cannot detach valgrind unless you exec() a new binary on top. However, valgrind and lxc do not play nicely, at least with the versions in Ubuntu 12.04 LTS. I’m getting an error back from lxc_start(). I’m having trouble getting logs to see why its failing, so I don’t know exactly what’s failing, yet.<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>But, I’m looking for any ideas for getting valgrind to work with programs that use lxc_start().<o:p></o:p></p><p class=MsoNormal>Any suggestions will be welcome. And, thanks!<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Regards.</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <br></span><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>Mark K Vallevand</span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'> <o:p></o:p></span></p><p class=MsoNormal><span style='font-size:10.0pt;font-family:"Arial","sans-serif"'>"If there are no dogs in Heaven, then when I die I want to go where they went."<br>-Will Rogers<br></span><span style='font-size:12.0pt;font-family:"Times New Roman","serif"'><br></span><span style='font-size:10.0pt;font-family:"Times New Roman","serif"'>THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.</span><o:p></o:p></p></div></body></html>