Commit 0a68ff5e authored by Kees Cook's avatar Kees Cook Committed by Jeff Layton

fcntl: 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.

fs/fcntl.c: In function ‘send_sigio_to_task’:
fs/fcntl.c:738:20: warning: statement will never be executed [-Wswitch-unreachable]
  738 |   kernel_siginfo_t si;
      |                    ^~

[1] https://bugs.llvm.org/show_bug.cgi?id=44916Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarJeff Layton <jlayton@kernel.org>
parent 98d54f81
......@@ -735,8 +735,9 @@ static void send_sigio_to_task(struct task_struct *p,
return;
switch (signum) {
default: {
kernel_siginfo_t si;
default:
/* Queue a rt signal with the appropriate fd as its
value. We use SI_SIGIO as the source, not
SI_KERNEL, since kernel signals always get
......@@ -769,6 +770,7 @@ static void send_sigio_to_task(struct task_struct *p,
si.si_fd = fd;
if (!do_send_sig_info(signum, &si, p, type))
break;
}
/* fall-through - fall back on the old plain SIGIO signal */
case 0:
do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);
......
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