Bug#826646: Incorrect handling with initial_cwd variable

[Серж ИвановЪ]

I would like to point out that this bug also affects current debian stable
exim package.
To verify one would need to examine exim source package for debian jessie

apt-get source exim4
grep -A 8 "To be safe: change the working directory to"
./exim4-4.84.2/src/exim.c

"""
/* To be safe: change the working directory to /. */
if (Uchdir("/") < 0)
  {
    perror("exim: chdir `/': ");
    exit(EXIT_FAILURE);
  }

/* Store the initial cwd before we change directories */
if ((initial_cwd = getcwd(NULL, 0)) == NULL)
"""

This is exactly the same error as in oldstable, we are doing chroot BEFORE
initial_cwd handling

​So this upstream patch is also applicable
https://github.com/Exim/exim/commit/3de973a29de6852d61ba9bf1845835d08ca5a5ab#diff-6e46fb11179cb7da978360d317a92ee0

Do I need to file a bug report for debian jessie (exim4-4.84) version?

Thanks