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authorKees Cook <keescook@chromium.org>2020-02-19 22:23:13 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-02-23 20:14:50 +0100
commite24cd4e6d6aa3ca741cdfdfc01118c4016acebea (patch)
tree907c0834a1fc76d73ceec9244f33cf6d254d25b8 /drivers/tty/n_tty.c
parente587e8f17433ddb26954f0edf5b2f95c42155ae9 (diff)
downloadlinux-e24cd4e6d6aa3ca741cdfdfc01118c4016acebea.tar.bz2
n_tty: 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. drivers/tty/n_tty.c: In function ‘__process_echoes’: drivers/tty/n_tty.c:657:18: warning: statement will never be executed [-Wswitch-unreachable] 657 | unsigned int num_chars, num_bs; | ^~~~~~~~~ [1] https://bugs.llvm.org/show_bug.cgi?id=44916 Reviewed-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20200220062313.69209-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/n_tty.c')
-rw-r--r--drivers/tty/n_tty.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index 640fdd1e4c1d..1794d84e7bf6 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -654,9 +654,9 @@ static size_t __process_echoes(struct tty_struct *tty)
op = echo_buf(ldata, tail + 1);
switch (op) {
+ case ECHO_OP_ERASE_TAB: {
unsigned int num_chars, num_bs;
- case ECHO_OP_ERASE_TAB:
if (MASK(ldata->echo_commit) == MASK(tail + 2))
goto not_yet_stored;
num_chars = echo_buf(ldata, tail + 2);
@@ -687,7 +687,7 @@ static size_t __process_echoes(struct tty_struct *tty)
}
tail += 3;
break;
-
+ }
case ECHO_OP_SET_CANON_COL:
ldata->canon_column = ldata->column;
tail += 2;