| Message ID | 1438581450-20728-1-git-send-email-k.kozlowski@samsung.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Jiri Kosina |
| Headers | show |
On Mon, Aug 03, 2015 at 02:57:30PM +0900, Krzysztof Kozlowski wrote: > During unbinding the driver was dereferencing a pointer to memory > already freed by power_supply_unregister(). > > Driver was freeing its internal description of battery through pointers > stored in power_supply structure. However, because the core owns the > power supply instance, after calling power_supply_unregister() this > memory is freed and the driver cannot access these members. > > Fix this by storing the pointer to internal description of battery in a > local variable before calling power_supply_unregister(), so the pointer > remains valid. > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Reported-by: H.J. Lu <hjl.tools@gmail.com> > Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") > Cc: <stable@vger.kernel.org> > FWIW: Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> > --- > Changes since v2: > 1. Add missing 'const'. > > Changes since v1: > 1. Re-work idea, use local variable instead of devm-like functions > (pointed out by Dmitry Torokhov). > 2. Adjusted subject and commit message. > --- > drivers/hid/hid-input.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c > index 14aebe483219..53aeaf6252c7 100644 > --- a/drivers/hid/hid-input.c > +++ b/drivers/hid/hid-input.c > @@ -462,12 +462,15 @@ out: > > static void hidinput_cleanup_battery(struct hid_device *dev) > { > + const struct power_supply_desc *psy_desc; > + > if (!dev->battery) > return; > > + psy_desc = dev->battery->desc; > power_supply_unregister(dev->battery); > - kfree(dev->battery->desc->name); > - kfree(dev->battery->desc); > + kfree(psy_desc->name); > + kfree(psy_desc); > dev->battery = NULL; > } > #else /* !CONFIG_HID_BATTERY_STRENGTH */ > -- > 1.9.1 >
On Mon, 3 Aug 2015, Krzysztof Kozlowski wrote: > During unbinding the driver was dereferencing a pointer to memory > already freed by power_supply_unregister(). > > Driver was freeing its internal description of battery through pointers > stored in power_supply structure. However, because the core owns the > power supply instance, after calling power_supply_unregister() this > memory is freed and the driver cannot access these members. > > Fix this by storing the pointer to internal description of battery in a > local variable before calling power_supply_unregister(), so the pointer > remains valid. > > Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> > Reported-by: H.J. Lu <hjl.tools@gmail.com> > Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") > Cc: <stable@vger.kernel.org> Applied to for-4.2/upstream-fixes-devm-fixed, and thanks again Dmitry for catching my mistake.
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c index 14aebe483219..53aeaf6252c7 100644 --- a/drivers/hid/hid-input.c +++ b/drivers/hid/hid-input.c @@ -462,12 +462,15 @@ out: static void hidinput_cleanup_battery(struct hid_device *dev) { + const struct power_supply_desc *psy_desc; + if (!dev->battery) return; + psy_desc = dev->battery->desc; power_supply_unregister(dev->battery); - kfree(dev->battery->desc->name); - kfree(dev->battery->desc); + kfree(psy_desc->name); + kfree(psy_desc); dev->battery = NULL; } #else /* !CONFIG_HID_BATTERY_STRENGTH */
During unbinding the driver was dereferencing a pointer to memory already freed by power_supply_unregister(). Driver was freeing its internal description of battery through pointers stored in power_supply structure. However, because the core owns the power supply instance, after calling power_supply_unregister() this memory is freed and the driver cannot access these members. Fix this by storing the pointer to internal description of battery in a local variable before calling power_supply_unregister(), so the pointer remains valid. Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com> Reported-by: H.J. Lu <hjl.tools@gmail.com> Fixes: 297d716f6260 ("power_supply: Change ownership from driver to core") Cc: <stable@vger.kernel.org> --- Changes since v2: 1. Add missing 'const'. Changes since v1: 1. Re-work idea, use local variable instead of devm-like functions (pointed out by Dmitry Torokhov). 2. Adjusted subject and commit message. --- drivers/hid/hid-input.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)