<html><body><div style="font-family: arial, helvetica, sans-serif; font-size: 12pt; color: #000000"><div><span id="zwchr" data-marker="__DIVIDER__">----- On Jul 12, 2016, at 7:05 AM, Aravind HT <aravind.ht@gmail.com> wrote:<br></span></div><div data-marker="__QUOTED_TEXT__"><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><div dir="ltr">Hi,<br><div>Below is a recent core that I saw. Unfortunately the code is optimized, but still it points to a call to free(lttng_chan);</div><br><div><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black">(gdb) bt
#0 0x00007f3cbb0df367 in __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:55
#1 0x00007f3cbb0e233a in __GI_abort () at abort.c:89
#2 0x00007f3cbb11928c in __libc_message (do_abort=do_abort@entry=2, fmt=fmt@entry=0x7f3cbb2158c8 "*** Error in `%s': %s: 0x%s ***\n") at ../sysdeps/posix/libc_fatal.c:175
#3 0x00007f3cbb122cbe in malloc_printerr (action=3, str=0x7f3cbb211a87 "free(): invalid pointer", ptr=<optimized out>) at malloc.c:4960
#4 0x00007f3cbb12349b in _int_free (av=<optimized out>, p=<optimized out>, have_lock=0) at malloc.c:3831
#5 0x00007f3cb79551c5 in lttng_abi_map_channel () from /var/tmp/iso-path.24284/altroot/usr/lib64/liblttng-ust.so.0
#6 0x00007f3cb79554c8 in ?? () from /var/tmp/iso-path.24284/altroot/usr/lib64/liblttng-ust.so.0
#7 0x00007f3cb7952846 in ?? () from /var/tmp/iso-path.24284/altroot/usr/lib64/liblttng-ust.so.0
#8 0x00007f3cb8974294 in start_thread (arg=0x7f3cb1ad7700) at pthread_create.c:336
#9 0x00007f3cbb19413d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:109</pre><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black"><br></pre><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black">Think we should not be freeing lttng_chan here.</pre><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black"><span style="font-family:arial,sans-serif"><br></span></pre><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black"><span style="font-family:arial,sans-serif"><a href="https://github.com/dgoulet/lttng-ust-dev/blob/master/liblttng-ust/lttng-ust-abi.c#L516" target="_blank">https://github.com/dgoulet/lttng-ust-dev/blob/master/liblttng-ust/lttng-ust-abi.c#L516</a></span><br data-mce-bogus="1"></pre></div></div></blockquote><div>By the way, this is an old repository. You should refer to https://github.com/lttng/lttng-ust/<br></div><div>instead.<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>There is indeed an issue there. I pushed the following fix into master,<br data-mce-bogus="1"></div><div>cherry-picked into stable 2.7 and 2.8:<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>commit 3eae1fb99c6821530888b470528299ff187021a8<br>Author: Mathieu Desnoyers <mathieu.desnoyers@efficios.com><br>Date: Tue Jul 12 09:51:40 2016 -0400<br><br> Fix: remove invalid free<br> <br> On this error path, we should not free lttng_chan, because it is located<br> within an allocated shm memory area associated with the channel now. It<br> is invalid to free this pointer.<br> <br> This is invoked on a channel creation error path.<br> <br> Reported-by: Aravind HT <aravind.ht@gmail.com><br> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com></div><div><br data-mce-bogus="1"></div><div>Thanks,<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div>Mathieu<br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><div><br data-mce-bogus="1"></div><blockquote style="border-left:2px solid #1010FF;margin-left:5px;padding-left:5px;color:#000;font-weight:normal;font-style:normal;text-decoration:none;font-family:Helvetica,Arial,sans-serif;font-size:12pt;"><div dir="ltr"><div><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black"><br></pre><pre style="margin-top:0px;margin-bottom:0px;padding:0px;white-space:pre-wrap;word-wrap:break-word;font-size:13px;color:black">Regards,
Aravind.</pre></div></div><br>_______________________________________________<br>lttng-dev mailing list<br>lttng-dev@lists.lttng.org<br>https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev<br></blockquote></div><div><br></div><div data-marker="__SIG_POST__">-- <br></div><div>Mathieu Desnoyers<br>EfficiOS Inc.<br>http://www.efficios.com</div></div></body></html>