On Wed, Jun 03, 2020 at 04:31:53PM -0700, Kees Cook wrote:
Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.
As recommended[2] by[3] Linus[4], remove the macro.
Most of the 300 uses don't cause any warnings on gcc 9.3.0, so they're in
a single treewide commit in this series. A few others needed to actually
get cleaned up, and I broke those out into individual patches.
-Kees
[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/ (local)
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/ (local)
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/ (local)
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/ (local)
Kees Cook (10):
x86/mm/numa: Remove uninitialized_var() usage
drbd: Remove uninitialized_var() usage
b43: Remove uninitialized_var() usage
rtlwifi: rtl8192cu: Remove uninitialized_var() usage
ide: Remove uninitialized_var() usage
clk: st: Remove uninitialized_var() usage
spi: davinci: Remove uninitialized_var() usage
checkpatch: Remove awareness of uninitialized_var() macro
treewide: Remove uninitialized_var() usage
compiler: Remove uninitialized_var() macro
I applied all of these on top of cb8e59cc8720 and ran a variety of
builds with clang for arm32, arm64, mips, powerpc, s390, and x86_64 [1]
and only saw one warning pop up (which was about a variable being
unused, commented on patch 9 about it). No warnings about uninitialized
variables came up; clang's -Wuninitialized was not impacted by
78a5255ffb6a ("Stop the ad-hoc games with -Wno-maybe-initialized") so it
should have caught anything egregious.
[1]: https://github.com/nathanchance/llvm-kernel-testing
For the series, consider it:
Tested-by: Nathan Chancellor <redacted> [build]