Messages in this thread | | | Date | Mon, 24 Feb 2020 12:34:12 +0000 | From | Sudip Mukherjee <> | Subject | Re: [PATCH] ppdev: Distribute switch variables for initialization |
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On Wed, Feb 19, 2020 at 10:23:11PM -0800, Kees Cook wrote: > Variables declared in a switch statement before any case statements > cannot be automatically initialized with compiler instrumentation (as > they are not part of any execution flow). With GCC's proposed automatic > stack variable initialization feature, this triggers a warning (and they > don't get initialized). Clang's automatic stack variable initialization > (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also > doesn't initialize such variables[1]. Note that these warnings (or silent > skipping) happen before the dead-store elimination optimization phase, > so even when the automatic initializations are later elided in favor of > direct initializations, the warnings remain. > > To avoid these problems, move such variables into the "case" where > they're used or lift them up into the main function body. > > drivers/char/ppdev.c: In function ‘pp_do_ioctl’: > drivers/char/ppdev.c:516:25: warning: statement will never be executed [-Wswitch-unreachable] > 516 | struct ieee1284_info *info; > | ^~~~ > > [1] https://bugs.llvm.org/show_bug.cgi?id=44916 > > Signed-off-by: Kees Cook <keescook@chromium.org>
Acked-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Greg, Can you please take it in your tree...
-- Regards Sudip
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