• Yanjiang Jin's avatar
    pinctrl: core: make sure strcmp() doesn't get a null parameter · 54a58185
    Yanjiang Jin authored
    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: 's avatarYanjiang Jin <yanjiang.jin@hxt-semitech.com>
    Signed-off-by: 's avatarLinus Walleij <linus.walleij@linaro.org>
    54a58185
core.c 56.2 KB