Commit 30161f6b2e7d1 (Input: gpio_keys - clean up device tree parser) introduced the following kernel crash for a dt based kernel: .. Unable to handle kernel NULL pointer dereference at virtual address 00000004 pgd = 80004000 [00000004] *pgd=00000000 Internal error: Oops: 805 [#1] ARM Modules linked in: CPU: 0 Not tainted (3.5.0-next-20120802+ #1366) PC is at gpio_keys_probe+0x154/0x8c0 LR is at of_gpiochip_find_and_xlate+0x54/0x70 pc : [<803ddbac>] lr : [<801ed2f4>] psr: 60000013 sp : 9f851df8 ip : 00000002 fp : 9f851e5c r10: 9f873d00 r9 : 00000001 r8 : 9fa2f900 r7 : 809c0920 r6 : 9f873d08 r5 : 00000000 r4 : 809c09d4 r3 : 805af10c r2 : 000000c0 r1 : 9f851db4 r0 : 000000d5 Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment kernel Control: 10c5387d Table: 90004019 DAC: 00000015 Process swapper (pid: 1, stack limit = 0x9f8502e8) Stack: (0x9f851df8 to 0x9f852000) ....
The reason for the crash was due to 'button = &pdata->buttons[i++];' returning a NULL pointer, and then 'button' was accessed afterwards without checking for NULL. Fix this by correctly assigning 'pdata->buttons' and also add a NULL pointer check for 'button' pointer. Signed-off-by: Fabio Estevam <[email protected]> Acked-by: Alexandre Pereira da Silva <[email protected]> --- drivers/input/keyboard/gpio_keys.c | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff --git a/drivers/input/keyboard/gpio_keys.c b/drivers/input/keyboard/gpio_keys.c index 6ee68ec..620ef24 100644 --- a/drivers/input/keyboard/gpio_keys.c +++ b/drivers/input/keyboard/gpio_keys.c @@ -559,7 +559,6 @@ gpio_keys_get_devtree_pdata(struct device *dev) struct gpio_keys_button *button; int error; int nbuttons; - int i; node = dev->of_node; if (!node) { @@ -580,9 +579,11 @@ gpio_keys_get_devtree_pdata(struct device *dev) goto err_out; } + pdata->buttons = (struct gpio_keys_button *) (pdata + 1); + pdata->nbuttons = nbuttons; + pdata->rep = !!of_get_property(node, "autorepeat", NULL); - i = 0; for_each_child_of_node(node, pp) { enum of_gpio_flags flags; @@ -592,8 +593,13 @@ gpio_keys_get_devtree_pdata(struct device *dev) continue; } - button = &pdata->buttons[i++]; - + button = pdata->buttons; + + if (!button) { + error = -ENOMEM; + goto err_free_pdata; + } + button->gpio = of_get_gpio_flags(pp, 0, &flags); button->active_low = flags & OF_GPIO_ACTIVE_LOW; @@ -614,6 +620,8 @@ gpio_keys_get_devtree_pdata(struct device *dev) if (of_property_read_u32(pp, "debounce-interval", &button->debounce_interval)) button->debounce_interval = 5; + + button++; } if (pdata->nbuttons == 0) { -- 1.7.1 -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
