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1475ce4ff9
[ Upstream commit 54a58185bf ]
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>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.