Re: [PATCH] ide-cd: fix kernel crash on hppa regression

From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
To: petkovbb@gmail.com
Cc: Helge Deller <deller@gmx.de>,
	Linus <torvalds@linux-foundation.org>,
	Borislav Petkov <petkovbb@googlemail.com>,
	Kyle McMartin <kyle@mcmartin.ca>,
	"linux-parisc" <linux-parisc@vger.kernel.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>
Subject: Re: [PATCH] ide-cd: fix kernel crash on hppa regression
Date: Wed, 22 Apr 2009 20:27:43 +0200	[thread overview]
Message-ID: <200904222027.44319.bzolnier@gmail.com> (raw)
In-Reply-To: <20090422061046.GA22451@liondog.tnic>

On Wednesday 22 April 2009 08:10:46 Borislav Petkov wrote:
> Hi,
> 
> On Thu, Apr 16, 2009 at 12:45:31AM +0200, Helge Deller wrote:
> > With 2.6.30-rc2 I face a kernel crash on the 32bit hppa architecture 
> > due to ide-cd when udev creates the device nodes at startup:
> > 
> > Kernel Fault: Code=26 regs=8ed34c40 (Addr=00000024)
> > IASQ: 00000000 00000000 IAOQ: 1034b5ac 1034b5b0
> >  IIR: 4ab30048    ISR: 00000000  IOR: 00000024
> >  CPU:        0   CR30: 8ed34000 CR31: ffff55ff
> >  ORIG_R28: 00000000
> >  IAOQ[0]: ide_complete_rq+0x2c/0x70
> >  IAOQ[1]: ide_complete_rq+0x30/0x70
> >  RP(r2): cdrom_newpc_intr+0x178/0x46c
> > Backtrace:
> >  [<1035c608>] cdrom_newpc_intr+0x178/0x46c
> >  [<1034c494>] ide_intr+0x1b0/0x214
> >  [<1016d284>] handle_IRQ_event+0x70/0x150
> >  [<1016d4b0>] __do_IRQ+0x14c/0x1cc
> >  [<102f7864>] superio_interrupt+0x88/0xbc
> >  [<1016d284>] handle_IRQ_event+0x70/0x150
> >  [<1016d4b0>] __do_IRQ+0x14c/0x1cc
> >  [<10112efc>] do_cpu_irq_mask+0x9c/0xd0
> >  [<10116068>] intr_return+0x0/0x4
> > 
> > This crash seems to happen due to an uninitialized variable "rc".
> > The compiler even warns about that:
> >   CC      drivers/ide/ide-cd.o                                                         
> > /mnt/sda4/home/cvs/parisc/git-kernel/linus-linux-2.6/drivers/ide/ide-cd.c: In function `cdrom_newpc_intr':
> > /mnt/sda4/home/cvs/parisc/git-kernel/linus-linux-2.6/drivers/ide/ide-cd.c:612: warning: `rc' might be used uninitialized in this function
> > 
> > After applying the trivial patch below, which just initializes 
> > the variable to zero, the kernel doesn't crash any longer:
> > 
> > Starting the hotplug events dispatcher: udevd.
> > Synthesizing the initial hotplug events...
> > hda: command error: status=0x51 { DriveReady SeekComplete Error }
> > hda: command error: error=0x54 <3>{ AbortedCommand LastFailedSense=0x05 }
> > ide: failed opcode was: unknown
> > done.
> > 
> > Signed-off-by: Helge Deller <deller@gmx.de>
> Acked-by: Borislav Petkov <petkovbb@gmail.com>
> 
> The original fix was correct. Helge, sorry for the delay but I wanted to
> make sure that this wasn't caused by recent rewrite in another area of
> ide-cd, thanks.
> 
> Bart, please apply.

Ok, done!