[ Upstream commit 54a58185bfafb5af5045fb8388c45daa373f90f3 ]
Some drivers, for example, QCOM's qdf2xxx, set groups[gpio].name only when gpio is valid, and leave invalid gpio names as null. If we want to access the sys node "pinconf-groups", pinctrl_get_group_selector() -> get_group_name() may return a null pointer if group_selector is invalid, then the below Kernel panic would happen since strcmp() uses this null pointer to do comparison.
Unable to handle kernel NULL pointer dereference at ss 00000000 el:Internal error: Oops: 9600000[ 143.080279] SMP CPU: 19 PID: 2493 Comm: read_all Tainted: G O .aarch64 #1 Hardware name: HXT Semiconductor HXT REP-2 System PC is at strcmp+0x18/0x154 LR is at pinctrl_get_group_selector+0x6c/0xe8 Process read_all (pid: 2493, stack limit = Call trace: Exception stack strcmp+0x18/0x154 pin_config_group_get+0x64/0xd8 pinconf_generic_dump_one+0xd8/0x1c0 pinconf_generic_dump_pins+0x94/0xc8 pinconf_groups_show+0xb4/0x104 seq_read+0x178/0x464 full_proxy_read+0x6c/0xac __vfs_read+0x58/0x178 vfs_read+0x94/0x164 SyS_read+0x60/0xc0 __sys_trace_return+0x0/0x4 --[ end trace]-- Kernel panic - not syncing: Fatal exception
Signed-off-by: Yanjiang Jin yanjiang.jin@hxt-semitech.com Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pinctrl/core.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index a3dd777e3ce8..c6ff4d5fa482 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -627,7 +627,7 @@ static int pinctrl_generic_group_name_to_selector(struct pinctrl_dev *pctldev, while (selector < ngroups) { const char *gname = ops->get_group_name(pctldev, selector);
- if (!strcmp(function, gname)) + if (gname && !strcmp(function, gname)) return selector;
selector++; @@ -743,7 +743,7 @@ int pinctrl_get_group_selector(struct pinctrl_dev *pctldev, while (group_selector < ngroups) { const char *gname = pctlops->get_group_name(pctldev, group_selector); - if (!strcmp(gname, pin_group)) { + if (gname && !strcmp(gname, pin_group)) { dev_dbg(pctldev->dev, "found group selector %u for %s\n", group_selector,