On Wed, Sep 16, 2020 at 10:35 AM Greg Rose <[email protected]> wrote:
>
> From: Kees Cook <[email protected]>
>
> Upstream commit:
> commit 16a556eeb7ed2dc3709fe2c5be76accdfa4901ab
> Author: Kees Cook <[email protected]>
> Date: Wed Feb 19 22:23:09 2020 -0800
>
> openvswitch: Distribute switch variables for initialization
>
> 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.
>
> net/openvswitch/flow_netlink.c: In function ‘validate_set’:
> net/openvswitch/flow_netlink.c:2711:29: warning: statement will never be
> executed [-Wswitch-unreachable]
> 2711 | const struct ovs_key_ipv4 *ipv4_key;
> | ^~~~~~~~
>
> [1] https://bugs.llvm.org/show_bug.cgi?id=44916
>
> Signed-off-by: Kees Cook <[email protected]>
> Signed-off-by: David S. Miller <[email protected]>
>
> Cc: Kees Cook <[email protected]>
> Signed-off-by: Greg Rose <[email protected]>
> ---
Acked-by: Yi-Hung Wei <[email protected]>
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