Re: 2.5.73-mm1 Uninitialised timer warnings

[Shane Shrybman]

Thanks for the patch. Sorry for the repost.

On Fri, 2003-06-27 at 15:58, Mikael Pettersson wrote:
> On 27 Jun 2003 11:23:59 -0400, Shane Shrybman wrote:
> >Below is my dmesg output which contains several uninitialized timer
> >warnings. I assume someone wants to see them or else why print the
> >warning. :-)
> >
> >BTW: Only three warnings during the compile of this kernel!
> >
> >Linux version 2.5.73-mm1 ([e-mail]) (gcc version 2.96
> >20000731 (Mandrake Linux 8.2 2.96-0.76mdk)) #1 Fri Jun 27 10:47:16 EDT
> >2003
> ...
> >Uninitialised timer!
> >This is just a warning.  Your computer is OK
> >function=0xc01e9d60, data=0x0
> >Call Trace:
> > [<c0123a6e>] check_timer_failed+0x3e/0x50
> > [<c01e9d60>] floppy_shutdown+0x0/0xb0
> > [<c0123de8>] del_timer+0x18/0xb0
> > [<c01e0321>] blk_init_queue+0x111/0x130
> > [<c01e7ac1>] reschedule_timeout+0x21/0xa0
> > [<c0304274>] floppy_init+0x144/0x530
> > [<c01ec080>] do_fd_request+0x0/0x90
> > [<c02f2789>] do_initcalls+0x39/0x90
> > [<c0105098>] init+0x38/0x1a0
> > [<c0105060>] init+0x0/0x1a0
> > [<c0108a19>] kernel_thread_helper+0x5/0xc
> >
> >Floppy drive(s): fd0 is 1.44M
> 
> These warnings as the same as those resulting from building
> 2.5.73 with gcc-2.95, i.e., they are the result of gcc miscompiling
> the empty structs that spinlocks reduce to on UP.
> 
> It's interesting to note that your Mandrake gcc-2.96 has this bug,
> which previously was thought to be limited to gcc-2.95 and older.
> 
> Anyway, the fix is to revert patch-2.5.73's change to linux/spinlock.h.
> The latest 2.5.73-bk includes the fix, or apply the patch below.
> 
> /Mikael
> 
> --- linux-2.5.73/include/linux/spinlock.h.~1~	2003-06-23 13:07:39.000000000 +0200
> +++ linux-2.5.73/include/linux/spinlock.h	2003-06-23 22:58:29.000000000 +0200
> @@ -146,8 +146,13 @@
>  /*
>   * gcc versions before ~2.95 have a nasty bug with empty initializers.
>   */
> -typedef struct { } spinlock_t;
> -#define SPIN_LOCK_UNLOCKED (spinlock_t) { }
> +#if (__GNUC__ > 2)
> +  typedef struct { } spinlock_t;
> +  #define SPIN_LOCK_UNLOCKED (spinlock_t) { }
> +#else
> +  typedef struct { int gcc_is_buggy; } spinlock_t;
> +  #define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
> +#endif
>  
>  /*
>   * If CONFIG_SMP is unset, declare the _raw_* definitions as nops