| Message ID | 1562574721-125584-1-git-send-email-mine260309@gmail.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [linux,dev-5.1] hwmon (occ): Fix division by zero issue | expand |
On 7/8/19 3:32 AM, Lei YU wrote: > The code in occ_get_powr_avg() invokes div64_u64() without checking the > divisor. In case the divisor is zero, kernel gets an "Division by zero > in kernel" error. > > Check the divisor and make it return 0 if the divisor is 0. Thanks! Reviewed-by: Eddie James <eajames@linux.ibm.com> > > Signed-off-by: Lei YU <mine260309@gmail.com> > --- > drivers/hwmon/occ/common.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c > index e9d7167..15c5d43 100644 > --- a/drivers/hwmon/occ/common.c > +++ b/drivers/hwmon/occ/common.c > @@ -406,8 +406,10 @@ static ssize_t occ_show_power_1(struct device *dev, > > static u64 occ_get_powr_avg(u64 *accum, u32 *samples) > { > - return div64_u64(get_unaligned_be64(accum) * 1000000ULL, > - get_unaligned_be32(samples)); > + u64 divisor = get_unaligned_be32(samples); > + > + return (divisor == 0) ? 0 : > + div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor); > } > > static ssize_t occ_show_power_2(struct device *dev,
On Mon, 8 Jul 2019 at 15:19, Eddie James <eajames@linux.vnet.ibm.com> wrote: > > > On 7/8/19 3:32 AM, Lei YU wrote: > > The code in occ_get_powr_avg() invokes div64_u64() without checking the > > divisor. In case the divisor is zero, kernel gets an "Division by zero > > in kernel" error. > > > > Check the divisor and make it return 0 if the divisor is 0. > > > Thanks! > > Reviewed-by: Eddie James <eajames@linux.ibm.com> Merged into dev-5.2. Lei, can you please submit this to upstream? Please add Eddie's r-b to the commit message. Cheers, Joel > > > > > > Signed-off-by: Lei YU <mine260309@gmail.com> > > --- > > drivers/hwmon/occ/common.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c > > index e9d7167..15c5d43 100644 > > --- a/drivers/hwmon/occ/common.c > > +++ b/drivers/hwmon/occ/common.c > > @@ -406,8 +406,10 @@ static ssize_t occ_show_power_1(struct device *dev, > > > > static u64 occ_get_powr_avg(u64 *accum, u32 *samples) > > { > > - return div64_u64(get_unaligned_be64(accum) * 1000000ULL, > > - get_unaligned_be32(samples)); > > + u64 divisor = get_unaligned_be32(samples); > > + > > + return (divisor == 0) ? 0 : > > + div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor); > > } > > > > static ssize_t occ_show_power_2(struct device *dev, >
Sure, will do. On Thu, Jul 11, 2019 at 9:51 AM Joel Stanley <joel@jms.id.au> wrote: > > On Mon, 8 Jul 2019 at 15:19, Eddie James <eajames@linux.vnet.ibm.com> wrote: > > > > > > On 7/8/19 3:32 AM, Lei YU wrote: > > > The code in occ_get_powr_avg() invokes div64_u64() without checking the > > > divisor. In case the divisor is zero, kernel gets an "Division by zero > > > in kernel" error. > > > > > > Check the divisor and make it return 0 if the divisor is 0. > > > > > > Thanks! > > > > Reviewed-by: Eddie James <eajames@linux.ibm.com> > > Merged into dev-5.2. > > Lei, can you please submit this to upstream? Please add Eddie's r-b to > the commit message. > > Cheers, > > Joel > > > > > > > > > > > Signed-off-by: Lei YU <mine260309@gmail.com> > > > --- > > > drivers/hwmon/occ/common.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c > > > index e9d7167..15c5d43 100644 > > > --- a/drivers/hwmon/occ/common.c > > > +++ b/drivers/hwmon/occ/common.c > > > @@ -406,8 +406,10 @@ static ssize_t occ_show_power_1(struct device *dev, > > > > > > static u64 occ_get_powr_avg(u64 *accum, u32 *samples) > > > { > > > - return div64_u64(get_unaligned_be64(accum) * 1000000ULL, > > > - get_unaligned_be32(samples)); > > > + u64 divisor = get_unaligned_be32(samples); > > > + > > > + return (divisor == 0) ? 0 : > > > + div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor); > > > } > > > > > > static ssize_t occ_show_power_2(struct device *dev, > >
diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c index e9d7167..15c5d43 100644 --- a/drivers/hwmon/occ/common.c +++ b/drivers/hwmon/occ/common.c @@ -406,8 +406,10 @@ static ssize_t occ_show_power_1(struct device *dev, static u64 occ_get_powr_avg(u64 *accum, u32 *samples) { - return div64_u64(get_unaligned_be64(accum) * 1000000ULL, - get_unaligned_be32(samples)); + u64 divisor = get_unaligned_be32(samples); + + return (divisor == 0) ? 0 : + div64_u64(get_unaligned_be64(accum) * 1000000ULL, divisor); } static ssize_t occ_show_power_2(struct device *dev,
The code in occ_get_powr_avg() invokes div64_u64() without checking the divisor. In case the divisor is zero, kernel gets an "Division by zero in kernel" error. Check the divisor and make it return 0 if the divisor is 0. Signed-off-by: Lei YU <mine260309@gmail.com> --- drivers/hwmon/occ/common.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)