From: Tycho Andersen <tycho@tycho.ws>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jiri Slaby <jslaby@suse.com>,
"open list:SERIAL DRIVERS" <linux-serial@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
"Serge E . Hallyn" <serge@hallyn.com>
Subject: Re: [PATCH v3] uart: fix race between uart_put_char() and uart_shutdown()
Date: Fri, 6 Jul 2018 15:22:20 -0600 [thread overview]
Message-ID: <20180706212220.GC3583@cisco.lan> (raw)
In-Reply-To: <CAHp75VeAoL9aN4pX4G9WGPS4Oxi=G6PyF7qCCyZ1fNH=gKHYiw@mail.gmail.com>
On Fri, Jul 06, 2018 at 11:48:58PM +0300, Andy Shevchenko wrote:
> On Fri, Jul 6, 2018 at 9:39 PM, Tycho Andersen <tycho@tycho.ws> wrote:
> > On Fri, Jul 06, 2018 at 07:49:09PM +0300, Andy Shevchenko wrote:
> >> On Fri, Jul 6, 2018 at 7:24 PM, Tycho Andersen <tycho@tycho.ws> wrote:
>
> > but without the initialization I get,
> >
> > CC drivers/tty/serial/serial_core.o
> > In file included from ./include/linux/seqlock.h:36:0,
> > from ./include/linux/time.h:6,
> > from ./include/linux/stat.h:19,
> > from ./include/linux/module.h:10,
> > from drivers/tty/serial/serial_core.c:10:
> > drivers/tty/serial/serial_core.c: In function ‘uart_startup.part.20’:
> > ./include/linux/spinlock.h:260:3: warning: ‘flags’ may be used uninitialized in this function -Wmaybe-uninitialized]
> > _raw_spin_unlock_irqrestore(lock, flags); \
> > ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> > drivers/tty/serial/serial_core.c:184:22: note: ‘flags’ was declared here
> > unsigned long page, flags;
> > ^~~~~
>
> Hmm... I didn't see such warning. How you run make?
Just with `make`, although using the specific object file works too.
Perhaps it's gcc versions?
~/packages/linux uart-fix-v4 make drivers/tty/serial/serial_core.o
CALL scripts/checksyscalls.sh
DESCEND objtool
CC drivers/tty/serial/serial_core.o
In file included from ./include/linux/seqlock.h:36:0,
from ./include/linux/time.h:6,
from ./include/linux/stat.h:19,
from ./include/linux/module.h:10,
from drivers/tty/serial/serial_core.c:10:
drivers/tty/serial/serial_core.c: In function ‘uart_startup.part.20’:
./include/linux/spinlock.h:260:3: warning: ‘flags’ may be used uninitialized in this function -Wmaybe-uninitialized]
_raw_spin_unlock_irqrestore(lock, flags); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/serial_core.c:184:22: note: ‘flags’ was declared here
unsigned long page, flags;
^~~~~
In file included from ./include/linux/seqlock.h:36:0,
from ./include/linux/time.h:6,
from ./include/linux/stat.h:19,
from ./include/linux/module.h:10,
from drivers/tty/serial/serial_core.c:10:
drivers/tty/serial/serial_core.c: In function ‘uart_shutdown’:
./include/linux/spinlock.h:260:3: warning: ‘flags’ may be used uninitialized in this function -Wmaybe-uninitialized]
_raw_spin_unlock_irqrestore(lock, flags); \
^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/tty/serial/serial_core.c:269:16: note: ‘flags’ was declared here
unsigned long flags;
^~~~~
~/packages/linux uart-fix-v4 gcc --version
gcc (Ubuntu 7.3.0-16ubuntu3) 7.3.0
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
> Btw, you adding the only places with such assignments in this file.
> So, I would not do in your case, until entire file would be fixed.
>
> (But warning looks bogus, or you have some patches on top of current
> vanilla / next)
I don't have any patches, but I do admit to not thinking about it very hard and
adding initializations. I'll see if I can figure out what's going on.
Thanks,
Tycho
next prev parent reply other threads:[~2018-07-06 21:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-05 0:01 [PATCH] uart: fix race between uart_put_char() and uart_shutdown() Tycho Andersen
2018-06-05 3:59 ` Serge E. Hallyn
2018-06-06 21:42 ` Tycho Andersen
2018-06-28 12:05 ` Greg Kroah-Hartman
2018-06-29 10:24 ` [PATCH v2] " Tycho Andersen
2018-06-29 16:43 ` Tycho Andersen
2018-07-06 14:39 ` Greg Kroah-Hartman
2018-07-06 16:24 ` [PATCH v3] " Tycho Andersen
2018-07-06 16:49 ` Andy Shevchenko
2018-07-06 18:39 ` Tycho Andersen
2018-07-06 20:48 ` Andy Shevchenko
2018-07-06 21:22 ` Tycho Andersen [this message]
2018-07-11 16:07 ` [PATCH v4] " Tycho Andersen
2018-07-11 19:24 ` Serge E. Hallyn
2018-07-11 19:49 ` Serge E. Hallyn
2018-07-11 20:00 ` Tycho Andersen
2018-07-12 15:05 ` Greg Kroah-Hartman
2018-07-12 9:03 ` Andy Shevchenko
2018-07-12 14:13 ` Tycho Andersen
2018-07-12 15:04 ` Greg Kroah-Hartman
2018-07-12 15:08 ` Tycho Andersen
2018-07-12 15:40 ` Greg Kroah-Hartman
2018-07-12 18:18 ` Tycho Andersen
2018-07-12 18:25 ` Greg Kroah-Hartman
2018-07-12 18:30 ` Tycho Andersen
2018-07-13 9:28 ` Greg Kroah-Hartman
2018-07-13 14:01 ` Tycho Andersen
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