[PATCH] drivers/tty/serial: deal with 8250_core.c uninitialized warning for good

From: Paul Gortmaker
Date: Wed Feb 19 2014 - 15:02:15 EST


Every couple of months, someone sends a patch to fix:

drivers/tty/serial/8250/8250_core.c: In function 'serial_unlink_irq_chain':
drivers/tty/serial/8250/8250_core.c:1712:2: warning: 'i' may be used uninitialized in this function [-Wuninitialized]

and they in turn get a NACK for their efforts, and are told that
their compiler is broken. This has been going on since at least
the year 2008: https://lkml.org/lkml/2008/11/24/433

Lets add a comment, so that subsequent patches don't get as far as
the maintainers or the mailing lists.

Cc: Alan Cox <alan@xxxxxxxxxxxxxxx>
Signed-off-by: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>

diff --git a/drivers/tty/serial/8250/8250_core.c b/drivers/tty/serial/8250/8250_core.c
index 69932b7556cf..747073b8c38a 100644
--- a/drivers/tty/serial/8250/8250_core.c
+++ b/drivers/tty/serial/8250/8250_core.c
@@ -1694,6 +1694,10 @@ static int serial_link_irq_chain(struct uart_8250_port *up)

static void serial_unlink_irq_chain(struct uart_8250_port *up)
{
+ /*
+ * yes, some broken gcc emit "warning: 'i' may be used uninitialized"
+ * but no, we are not going to take a patch that assigns NULL below.
+ */
struct irq_info *i;
struct hlist_node *n;
struct hlist_head *h;
--
1.8.5.2

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