Both %pE and %ph are unusable in kasprintf(), since the occurrence of
either will trigger an oops during the first vsnprintf call where
kasprintf tries to find the correct size to allocate. These oopses
could be papered over with somewhat smaller patches than these, but
then the return value from vsnprintf would still not reflect the
actual size needed. For %pE, this requires a change of semantics of
string_escape_mem and hence an annoyingly large diffstat.

Whether this is 3.20, 3.21 and/or -stable material (or /dev/null
material, for that matter ;-)) I'll leave to others to decide.

v2: Suggestions from Andy Shevchenko:

* Simpler fix of hex_string().

* The string_escape_mem change is split in two, 2/3 updating the
  internal helpers and 3/3 then changing the external interface.

Rasmus Villemoes (3):
  lib/vsprintf.c: Fix potential NULL deref in hex_string
  lib/string_helpers.c: Refactor string_escape_mem
  lib/string_helpers.c: Change semantics of string_escape_mem

 include/linux/string_helpers.h |  10 +--
 lib/string_helpers.c           | 191 ++++++++++++++++-------------------------
 lib/test-string_helpers.c      |  37 ++++----
 lib/vsprintf.c                 |  18 ++--
 net/sunrpc/cache.c             |   8 +-
 5 files changed, 111 insertions(+), 153 deletions(-)

-- 
2.1.3