diff options
authorKees Cook <keescook@chromium.org>2020-02-19 22:22:43 -0800
committerJeff Layton <jlayton@kernel.org>2020-03-03 10:55:06 -0500
commit0a68ff5e2e7cf2263674b7f0418b31e10b2a497f (patch)
parentLinux 5.6-rc4 (diff)
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=44916 Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Jeff Layton <jlayton@kernel.org>
1 files changed, 4 insertions, 2 deletions
diff --git a/fs/fcntl.c b/fs/fcntl.c
index 9bc167562ee8..2e4c0fa2074b 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -735,8 +735,9 @@ static void send_sigio_to_task(struct task_struct *p,
switch (signum) {
- kernel_siginfo_t si;
- default:
+ default: {
+ kernel_siginfo_t si;
/* 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))
+ }
/* fall-through - fall back on the old plain SIGIO signal */
case 0:
do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, type);