kconfig: Don't leak main menus during parsing
authorUlf Magnusson <ulfalizer@gmail.com>
Sun, 8 Oct 2017 17:11:21 +0000 (19:11 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 26 Apr 2018 09:02:08 +0000 (11:02 +0200)
commit8bf116b258c286137635542a752ec68ffebd809b
treee2a0e5ca3dbb9712abd19631eef501adf9e991e9
parent9f2df99f9eb020a1fa4fceb460d9a494c3b33341
kconfig: Don't leak main menus during parsing

[ Upstream commit 0724a7c32a54e3e50d28e19e30c59014f61d4e2c ]

If a 'mainmenu' entry appeared in the Kconfig files, two things would
leak:

- The 'struct property' allocated for the default "Linux Kernel
  Configuration" prompt.

- The string for the T_WORD/T_WORD_QUOTE prompt after the
  T_MAINMENU token, allocated on the heap in zconf.l.

To fix it, introduce a new 'no_mainmenu_stmt' nonterminal that matches
if there's no 'mainmenu' and adds the default prompt. That means the
prompt only gets allocated once regardless of whether there's a
'mainmenu' statement or not, and managing it becomes simple.

Summary from Valgrind on 'menuconfig' (ARCH=x86) before the fix:

LEAK SUMMARY:
   definitely lost: 344,568 bytes in 14,352 blocks
   ...

Summary after the fix:

LEAK SUMMARY:
   definitely lost: 344,440 bytes in 14,350 blocks
   ...

Signed-off-by: Ulf Magnusson <ulfalizer@gmail.com>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
scripts/kconfig/zconf.y