Thanks Luke for your response. This is good information. According to the man page for backtrace, it indicates that "backtrace(), backtrace_symbols(), and backtrace_symbols_fd() are provided in glibc since version 2.1". Sorry for any confusion on this. Unfortunately, my glibc is apparently older than 2.1. I am not sure exactly how to tell how old... the usual method to try to run the libc.so.1 to get the version number results in a segmentation fault. Ldd --version is not understood by ldd as well. I also tried to use the gnu_get_libc_version() function that is supposed to always work, but it does not exist on my system. I think my glibc is very old... libc-so.1 vs libc-so.6 I am seeing commonly referenced. Sigh.
So to summarize, my linux kernel is 3.14.77, glibc is old (version ????), and gcc is 4.8.3. Anyhow, I am being unsuccessful at getting libunwind working too. It prints one stack backtrace step for __clone + 80 and then exits. I know there is one function call from the signal handler to get to the backtrace() function, so this looks bogus. I just need a backtrace capability that works. This is an embedded linux environment and I am restricted as to software updates I can do, so I think I am between a rock and a hard place. John -----Original Message----- From: Luke Diamand <l...@diamand.org> Sent: Tuesday, May 22, 2018 1:50 AM To: John Knight <john.kni...@belkin.com> Cc: libunwind-devel@nongnu.org Subject: Re: [Libunwind-devel] Minimum Linux Version requirements for libunwind? On 22 May 2018 at 00:55, John Knight <john.kni...@belkin.com> wrote: > Hi, > > > > I am trying to get libunwind to work on an ARM processor running an > older version of linx (version 3.14.77). I am wondering if there are > any particular requirements of the Linux kernel or supporting > libraries that would prohibit me from running on this older kernel? > If so, what is the minimum kernel version required for libunwind? I don't think it has any special kernel dependencies unless you're going to a really old kernel version (?). I'm using libunwind with 3.10. > > This kernel does NOT have support of backtrace()… my understanding is > that support came with glibc in version 3.2 which had kernel support > for it. The lack of a backtrace has led me to try and use libunwind > as an alternative to give me a stack backtrace when my program SEG faults. I didn't think backtrace was a kernel feature - doesn't it live in glibc? And uses unwind tables generated by gcc/g++ together with the unwinding code in libstdc++ (as per the ABI). If you're using glibc's backtrace() with unwind tables rather than frame pointer unwinding then you'll need a gcc that's new enough to generate it (and enable generation). That's been mostly there for a decade or more, but I think a bug was fixed recently (gcc 4.9.4/5.2 timeframe) for some obscure corner-cases. But back to your question, I think the oldest kernel version I've used libunwind with is 3.0 with glibc=2.18 and gcc=4.9. Luke __________________________________________________________________ Confidential This e-mail and any files transmitted with it are the property of Belkin International, Inc. and/or its affiliates, are confidential, and are intended solely for the use of the individual or entity to whom this e-mail is addressed. If you are not one of the named recipients or otherwise have reason to believe that you have received this e-mail in error, please notify the sender and delete this message immediately from your computer. Any other use, retention, dissemination, forwarding, printing or copying of this e-mail is strictly prohibited. Pour la version française: http://www.belkin.com/email-notice/French.html Für die deutsche Übersetzung: http://www.belkin.com/email-notice/German.html __________________________________________________________________ _______________________________________________ Libunwind-devel mailing list Libunwind-devel@nongnu.org https://lists.nongnu.org/mailman/listinfo/libunwind-devel
