Messages in this thread Patch in this message | | | From | Krzysztof Kozlowski <> | Subject | [PATCH v2] HID: hid-input: Fix accessing freed memory during device disconnect | Date | Mon, 03 Aug 2015 09:01:21 +0900 |
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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 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..460faaebaa2c 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) { + 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
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