Comment 14 for bug 1325503

Hi Maxim,

On Wed, Jun 25, 2014 at 11:51:51PM -0000, Maxim Kuvyrkov wrote:
> How was "sleep" and system glibc compiled?

> To get reliable stack traces GDB has to have access to either frame
> pointer (-fno-omit-frame-pointer compiler flag) or to unwind tables
> (-funwind-tables). In the absence of either of these, GDB has to guess
> where stack frame boundaries are. In this case GDB guesses wrong.

These binaries are built using the stock compiler flags in Ubuntu.

[...]
arm-linux-gnueabihf-gcc -std=gnu99 -g -O2 -fstack-protector -param=ssp-buffer-size=4 -Wformat -Werror=format-security -DSYSLOG_SUCCESS -DSYSLOG_FAILURE -DSYSLOG_NON_ROOT -Wl,--as-needed -Wl,-Bsymbolic-functions -Wl,-z,relro -o src/sleep src/sleep.o src/libver.a lib/libcoreutils.a lib/libcoreutils.a
[...]

  https://launchpad.net/ubuntu/+source/coreutils/8.21-1ubuntu5/+build/5843130
  https://launchpad.net/ubuntu/+source/coreutils/8.21-1ubuntu5/+build/5843130/+files/buildlog_ubuntu-trusty-armhf.coreutils_8.21-1ubuntu5_UPLOADING.txt.gz

> The recommended way to get reliable stack traces is to use -funwind-
> tables, which does not have performance penalty (like -fno-omit-frame-
> pointer), and only increases disk footprint of binaries by several
> percent.

If this is recommended, should it be turned on by default in gcc upstream?

Barring that, should we turn it on by default in our gcc build in Ubuntu, or
in our common distro compiler flags?

From Michael, I understand that "several percent" here is "on the order of
5%".

Thanks,
--
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Debian Developer to set it on, and I can move the world.
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