(cc Kees) On Thu, 10 Feb 2022 at 18:36, Victor Erminpour <victor.erminpour@xxxxxxxxxx> wrote: > > > On 2/10/22 1:11 AM, Ard Biesheuvel wrote: > > On Thu, 10 Feb 2022 at 01:34, Victor Erminpour > > <victor.erminpour@xxxxxxxxxx> wrote: > >> When building with automatic stack variable initialization, GCC 12 > >> complains about variables defined outside of switch case statements. > >> Move the variable into the case that uses it, which silences the warning: > >> > >> ./drivers/acpi/arm64/iort.c:1670:59: error: statement will never be executed [-Werror=switch-unreachable] > >> 1670 | struct acpi_iort_named_component *ncomp; > >> | ^~~~~ > >> > >> Signed-off-by: Victor Erminpour <victor.erminpour@xxxxxxxxxx> > > GCC 12 is not released yet, and this is clearly a compiler bug (a > > declaration is not a statement, and the hidden offending statement > > [the zero-init] is emitted by the compiler itself), so please report > > this to the GCC folks instead. > > Hi Ard, > > Thanks for the reply. > This fix is similar to the following commits that have been integrated > upstream: > https://lore.kernel.org/linux-hardening/20211209043456.1377875-1-keescook@xxxxxxxxxxxx/ > https://lore.kernel.org/linux-hardening/20211209043915.1378393-1-keescook@xxxxxxxxxxxx/ > If GCC 12 rejects valid C with this feature enabled, the compiler is broken and needs to be fixed. Papering over this by making changes to perfectly valid C code is a slippery slope that we should avoid. Since GCC 12 is not released yet, there is time to get this fixed properly. > You're not obligated to integrate this commit, Why, thank you :-) > but you may run into this > issue once > upstream starts using GCC 12 (or a patched version of GCC 11 in my case) > with the > CONFIG_INIT_STACK_ALL_ZERO option enabled. > Yes, that part was perfectly clear.
