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SubjectRe: [PATCH] hwmon: (w83627ehf): fix broken driver init
On Sat, Nov 05, 2011 at 04:13:51AM -0400, Jean Delvare wrote:
> Hi Alexander, Guenter,
>
> On Fri, 4 Nov 2011 21:51:56 -0700, Guenter Roeck wrote:
> > On Fri, Nov 04, 2011 at 08:54:10PM -0400, Alexander Beregalov wrote:
> > > Commit 2265cef2 (hwmon: (w83627ehf) Properly report PECI and AMD-SI
> > > sensor types) results in kernel panic if data->temp_label was not
> > > initialized.
> > > The problem was found with chip W83627DHG-P.
> > >
> > > backtrace:
> > > page_fault()
> > > w83627ehf_probe() 0x8e2
> > >
> > > w83627ehf_init_device:
> > > 1837: for (i = 0; i < 3; i++) {
> > > const char *label = data->temp_label[data->temp_src[i]];
> > >
> > > /* Digital source overrides analog type */
> > > if (strncmp(label, "PECI", 4) == 0)
> > > data->temp_type[i] = 6;
> > >
> > > movzbl 128(%r14), %edx # data->temp_src, tmp737
> > > movq 144(%r13), %rax # data_32->temp_label, data_32->temp_label
> > > movq $.LC18, %rsi #,
> > > movl %r14d, %r15d #, i
> > > subl %r13d, %r15d # D.29277, i
> > > 0x928 movq (%rax,%rdx,8), %rcx #* data_32->temp_label, label
> > > movl $4, %edx #,
> > > movq %rcx, %rdi # label,
> > > movq %rcx, -96(%rbp) #,
> > > call strncmp #
> > >
> > > page_fault() is called at 0x928 (0x8e2+0x46).
>
> Oops, my bad. I forgot that not all chips have temperature labels,
> sorry :( Thanks for reporting so quickly!
>
> > >
> > > Add check if data->temp->label was set before use.
> > >
> > > Cc: Jean Delvare <khali@linux-fr.org>
> > > Cc: Guenter Roeck <guenter.roeck@ericsson.com>
> > > Cc: stable@kernel.org
> > > Signed-off-by: Alexander Beregalov <a.beregalov@gmail.com>
> > > ---
> > > drivers/hwmon/w83627ehf.c | 17 +++++++++--------
> > > 1 files changed, 9 insertions(+), 8 deletions(-)
> > >
> > > diff --git a/drivers/hwmon/w83627ehf.c b/drivers/hwmon/w83627ehf.c
> > > index 483cb26..70f1c73 100644
> > > --- a/drivers/hwmon/w83627ehf.c
> > > +++ b/drivers/hwmon/w83627ehf.c
> > > @@ -1835,14 +1835,15 @@ static inline void __devinit w83627ehf_init_device(struct w83627ehf_data *data,
> > > diode = 0x70;
> > > }
> > > for (i = 0; i < 3; i++) {
> > > - const char *label = data->temp_label[data->temp_src[i]];
> > > -
> > > - /* Digital source overrides analog type */
> > > - if (strncmp(label, "PECI", 4) == 0)
> > > - data->temp_type[i] = 6;
> > > - else if (strncmp(label, "AMD", 3) == 0)
> > > - data->temp_type[i] = 5;
> > > - else if ((tmp & (0x02 << i)))
> > > + if (data->temp_label) {
> > > + const char *label = data->temp_label[data->temp_src[i]];
> > > +
> > > + /* Digital source overrides analog type */
> > > + if (strncmp(label, "PECI", 4) == 0)
> > > + data->temp_type[i] = 6;
> > > + else if (strncmp(label, "AMD", 3) == 0)
> > > + data->temp_type[i] = 5;
> > > + } else if ((tmp & (0x02 << i)))
> >
> > Followup - something like
> > const char *label = NULL;
> >
> > if (data->temp_label)
> > label = data->temp_label[data->temp_src[i]];
> >
> > /* Digital source overrides analog type */
> > if (label && strncmp(label, "PECI", 4) == 0)
> > data->temp_type[i] = 6;
> > else if (label && strncmp(label, "AMD", 3) == 0)
> > data->temp_type[i] = 5;
> > else if ((tmp & (0x02 << i)))
> >
> > should do it. I am open to better ideas...
>
> Looks good enough to me, this is one-time initialization code, it
> doesn't need to be lightning fast. Will you send a formal patch, or do
> you want me to do it?
>
I'll send one in a minute.

Guenter


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