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+[[!meta copyright="Copyright © 2010, 2012 Free Software Foundation, Inc."]]
+
+[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
+id="license" text="Permission is granted to copy, distribute and/or modify this
+document under the terms of the GNU Free Documentation License, Version 1.2 or
+any later version published by the Free Software Foundation; with no Invariant
+Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
+is included in the section entitled [[GNU Free Documentation
+License|/fdl]]."]]"""]]
+
+[[!tag open_issue_glibc]]
+
+
+# IRC, unknown channel, unknown date
+
+    <azeem> tschwinge: ext2fs.static: thread-cancel.c:55: hurd_thread_cancel: Assertion `! __spin_lock_locked (&ss->critical_section_lock)' failed.
+    <youpi> it'd be great if we could have backtraces in such case
+    <youpi> at least just the function names
+    <youpi> and in this case (static), just addresses would be enough
+
+
+# IRC, freenode, #hurd, 2012-07-19
+
+In context of the [[ext2fs_libports_reference_counting_assertion]].
+
+    <braunr> pinotree: tschwinge: do you know if our packages are built with
+      -rdynamic ?
+    <pinotree> braunr: debian's cflags don't include it, so unless the upstream
+      build systems do, -rdynamic is not added
+    <braunr> i doubt glibc' backtrace() is able to find debugging symbol files
+      on its own
+    <pinotree> what do you mean?
+    <braunr> the port reference bug youpi noticed is rare
+    <pinotree> even on linux, a program compiled with normal optimizations (eg
+      -O2 -g) can give just pointer values in backtrace()'s output
+    <braunr> core dumps are unreliable at best
+
+[[crash_server]].
+
+    <braunr> uh, no, backtrace does give names
+    <braunr> but not with -fomit-frame-pointer
+    <braunr> unless the binary is built with -rdynamic
+    <braunr> at least it used to
+    <pinotree> not really, when being optimized some steps can be optimized
+      away (eg inlines)
+    <braunr> that's ok
+    <braunr> anyway, the point is i'd like a way that can give us as much
+      information as possible when the problem happens
+    <braunr> the stack trace being the most useful imo
+    <pinotree> do you face issues currently with backtrace()?
+    <braunr> not tried yet
+    <braunr> i guess i could make the application trap in the kernel, and fault
+      there, so we can attach gdb while still in the pager address space :>
+    <pinotree> that would imply the need for interactivity when the fault
+      happens, wouldn't it?
+    <braunr> no
+    <braunr> it would remain this way until someone comes, hours, days later
+    <braunr> pinotree: well ok, it would require interactivity, but not *when*
+      it happens ;p
+    <braunr> pinotree: right, it needs -rdynamic
+
+
+## IRC, freenode, #hurd, 2012-07-21
+
+    <braunr> tschwinge: my current "approach" is to introduce an infinite loop
+    <braunr> it makes the faulting task mapped in often enough to use gdb
+      through qemu
+    <braunr> ... :)
+    <tschwinge> My understanding is that glibc already does have some mechanism
+      for that: I have seen it print backtraces whendetecting malloc
+      inconsistencies (double free and the lite).
+    <braunr> yes, i thought it used the backtrace functions internally though
+    <braunr> that is, execinfo
+    <braunr> but this does require -rdynamic
+
+
+# GCC's libbacktrace
+
+Introduced in GCC commit ecd3459e7bb829202601e3274411135a15c64dde.