On Fri, Jul 06, 2018 at 11:48:58PM +0300, Andy Shevchenko wrote:

On Fri, Jul 6, 2018 at 9:39 PM, Tycho Andersen [off-list ref] wrote:

quoted

On Fri, Jul 06, 2018 at 07:49:09PM +0300, Andy Shevchenko wrote:

quoted

On Fri, Jul 6, 2018 at 7:24 PM, Tycho Andersen [off-list ref] wrote:

quoted

 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