Douglas Anderson 1b8f1ab088 nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us ... [ Upstream commit 87ed1405ef ] In commit ca04d9d3e1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") you can see a call like: devm_nvmem_cell_get(dev, NULL); Note that the cell ID passed to the function is NULL. This is because the qcom-qusb2 driver is expected to work only on systems where the PHY node is hooked up via device-tree and is nameless. This works OK for the most part. The first thing nvmem_cell_get() does is to call of_nvmem_cell_get() and there it's documented that a NULL name is fine. The problem happens when the call to of_nvmem_cell_get() returns -EINVAL. In such a case we'll fall back to nvmem_cell_get_from_list() and eventually might (if nvmem_cells isn't an empty list) crash with something that looks like: strcmp nvmem_find_cell __nvmem_device_get nvmem_cell_get_from_list nvmem_cell_get devm_nvmem_cell_get qusb2_phy_probe There are several different ways we could fix this problem: One could argue that perhaps the qcom-qusb2 driver should be changed to use of_nvmem_cell_get() which is allowed to have a NULL name. In that case, we'd need to add a patche to introduce devm_of_nvmem_cell_get() since the qcom-qusb2 driver is using devm managed resources. One could also argue that perhaps we could just add a name to qcom-qusb2. That would be OK but I believe it effectively changes the device tree bindings, so maybe it's a no-go. In this patch I have chosen to fix the problem by simply not crashing when a NULL cell_id is passed to nvmem_cell_get(). NOTE: that for the qcom-qusb2 driver the "nvmem-cells" property is defined to be optional and thus it's expected to be a common case that we would hit this crash and this is more than just a theoretical fix. Fixes: ca04d9d3e1 ("phy: qcom-qusb2: New driver for QUSB2 PHY on Qcom chips") Signed-off-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-08-24 13:09:14 +02:00
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Kconfig	nvmem: Add driver for the i.MX IIM	2017-04-08 17:51:48 +02:00
Makefile	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
bcm-ocotp.c	nvmem: correct Broadcom OTP controller driver writes	2017-06-09 12:08:27 +02:00
core.c	nvmem: Don't let a NULL cell_id for nvmem_cell_get() crash us	2018-08-24 13:09:14 +02:00
imx-iim.c	nvmem: Add driver for the i.MX IIM	2017-04-08 17:51:48 +02:00
imx-ocotp.c	nvmem: imx-ocotp: add write support	2017-04-08 17:51:48 +02:00
lpc18xx_eeprom.c	nvmem: lpc18xx-eeprom: explicitly request exclusive reset control	2017-08-28 17:33:22 +02:00
lpc18xx_otp.c	nvmem: add NXP LPC18xx OTP driver	2016-11-10 15:34:55 +01:00
meson-efuse.c	firmware: meson-sm: Check for buffer output size	2017-03-23 12:22:32 -07:00
mtk-efuse.c	nvmem: mtk-efuse: remove nvmem regmap dependency	2016-06-25 07:42:55 -07:00
mxs-ocotp.c	nvmem: mxs-ocotp: remove nvmem regmap dependency	2016-06-25 07:42:55 -07:00
qfprom.c	nvmem: qfprom: Allow single byte accesses for read/write	2017-01-04 18:22:47 +01:00
rockchip-efuse.c	nvmem: rockchip-efuse: amend compatible rk322x-efuse to rk3228-efuse	2017-07-17 16:15:57 +02:00
sunxi_sid.c	nvmem: sunxi-sid: add support for H3's SID controller	2017-04-08 17:51:48 +02:00
vf610-ocotp.c	nvmem: vif610-ocotp: remove nvmem regmap dependency	2016-05-01 14:01:00 -07:00