When more than one GP timers are used as kernel system timers and the
corresponding nodes in device-tree are marked with the same "disabled"
property, then the "attr" field of the property will be initialized
more than once as the property being added to sys file system via
__of_add_property_sysfs().
In __of_add_property_sysfs(), the "name" field of pp->attr.attr is set
directly to the return value of safe_name(), without taking care of
whether it's already a valid pointer to a memory block. If it is, its
old value will always be overwritten by the new one and the memory block
allocated before will a "ghost", then a kmemleak happened.
That the same "disabled" property being added to different nodes of device
tree would cause that kind of kmemleak overhead, at leat once.
To fix it, allocate the property dynamically, and delete static one.
Signed-off-by: Qi Hou <[email protected]>
---
arch/arm/mach-omap2/timer.c | 19 +++++++++++--------
1 file changed, 11 insertions(+), 8 deletions(-)
diff --git a/arch/arm/mach-omap2/timer.c b/arch/arm/mach-omap2/timer.c
index ece09c9..0e6109b 100644
--- a/arch/arm/mach-omap2/timer.c
+++ b/arch/arm/mach-omap2/timer.c
@@ -156,12 +156,6 @@ static struct clock_event_device clockevent_gpt = {
.tick_resume = omap2_gp_timer_shutdown,
};
-static struct property device_disabled = {
- .name = "status",
- .length = sizeof("disabled"),
- .value = "disabled",
-};
-
static const struct of_device_id omap_timer_match[] __initconst = {
{ .compatible = "ti,omap2420-timer", },
{ .compatible = "ti,omap3430-timer", },
@@ -203,8 +197,17 @@ static struct device_node * __init omap_get_timer_dt(const struct of_device_id *
of_get_property(np, "ti,timer-secure", NULL)))
continue;
- if (!of_device_is_compatible(np, "ti,omap-counter32k"))
- of_add_property(np, &device_disabled);
+ if (!of_device_is_compatible(np, "ti,omap-counter32k")) {
+ struct property *prop;
+
+ prop = kzalloc(sizeof(*prop), GFP_KERNEL);
+ if (!prop)
+ return -ENOMEM;
+ prop->name = "status";
+ prop->length = sizeof("disabled");
+ prop->value = "disabled";
+ of_add_property(np, prop);
+ }
return np;
}
--
2.7.4
Hi Qi,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on omap/for-next]
[also build test WARNING on v4.15-rc7 next-20180108]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
url: https://github.com/0day-ci/linux/commits/Qi-Hou/arm-omap2-timer-fix-a-kmemleak-caused-in-omap_get_timer_dt/20180109-033316
base: https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git for-next
config: arm-omap2plus_defconfig (attached as .config)
compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm
All warnings (new ones prefixed by >>):
arch/arm/mach-omap2/timer.c: In function 'omap_get_timer_dt':
>> arch/arm/mach-omap2/timer.c:205:12: warning: return makes pointer from integer without a cast [-Wint-conversion]
return -ENOMEM;
^
vim +205 arch/arm/mach-omap2/timer.c
170
171 /**
172 * omap_get_timer_dt - get a timer using device-tree
173 * @match - device-tree match structure for matching a device type
174 * @property - optional timer property to match
175 *
176 * Helper function to get a timer during early boot using device-tree for use
177 * as kernel system timer. Optionally, the property argument can be used to
178 * select a timer with a specific property. Once a timer is found then mark
179 * the timer node in device-tree as disabled, to prevent the kernel from
180 * registering this timer as a platform device and so no one else can use it.
181 */
182 static struct device_node * __init omap_get_timer_dt(const struct of_device_id *match,
183 const char *property)
184 {
185 struct device_node *np;
186
187 for_each_matching_node(np, match) {
188 if (!of_device_is_available(np))
189 continue;
190
191 if (property && !of_get_property(np, property, NULL))
192 continue;
193
194 if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
195 of_get_property(np, "ti,timer-dsp", NULL) ||
196 of_get_property(np, "ti,timer-pwm", NULL) ||
197 of_get_property(np, "ti,timer-secure", NULL)))
198 continue;
199
200 if (!of_device_is_compatible(np, "ti,omap-counter32k")) {
201 struct property *prop;
202
203 prop = kzalloc(sizeof(*prop), GFP_KERNEL);
204 if (!prop)
> 205 return -ENOMEM;
206 prop->name = "status";
207 prop->length = sizeof("disabled");
208 prop->value = "disabled";
209 of_add_property(np, prop);
210 }
211 return np;
212 }
213
214 return NULL;
215 }
216
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
On 2018年01月09日 07:13, kbuild test robot wrote:
> Hi Qi,
>
> Thank you for the patch! Perhaps something to improve:
>
> [auto build test WARNING on omap/for-next]
> [also build test WARNING on v4.15-rc7 next-20180108]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Qi-Hou/arm-omap2-timer-fix-a-kmemleak-caused-in-omap_get_timer_dt/20180109-033316
> base: https://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git for-next
> config: arm-omap2plus_defconfig (attached as .config)
> compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=arm
>
> All warnings (new ones prefixed by >>):
>
> arch/arm/mach-omap2/timer.c: In function 'omap_get_timer_dt':
> >> arch/arm/mach-omap2/timer.c:205:12: warning: return makes pointer from integer without a cast [-Wint-conversion]
> return -ENOMEM;
Yes, it's problem.
I will correct it to "return NULL;".
As omap_get_timer_dt() is called in early time during booting up kernel,
that allocating a little size of memory should
always be alright. Return NULL just in case that it fails.
--
best regards,
Qi Hou
> ^
>
> vim +205 arch/arm/mach-omap2/timer.c
>
> 170
> 171 /**
> 172 * omap_get_timer_dt - get a timer using device-tree
> 173 * @match - device-tree match structure for matching a device type
> 174 * @property - optional timer property to match
> 175 *
> 176 * Helper function to get a timer during early boot using device-tree for use
> 177 * as kernel system timer. Optionally, the property argument can be used to
> 178 * select a timer with a specific property. Once a timer is found then mark
> 179 * the timer node in device-tree as disabled, to prevent the kernel from
> 180 * registering this timer as a platform device and so no one else can use it.
> 181 */
> 182 static struct device_node * __init omap_get_timer_dt(const struct of_device_id *match,
> 183 const char *property)
> 184 {
> 185 struct device_node *np;
> 186
> 187 for_each_matching_node(np, match) {
> 188 if (!of_device_is_available(np))
> 189 continue;
> 190
> 191 if (property && !of_get_property(np, property, NULL))
> 192 continue;
> 193
> 194 if (!property && (of_get_property(np, "ti,timer-alwon", NULL) ||
> 195 of_get_property(np, "ti,timer-dsp", NULL) ||
> 196 of_get_property(np, "ti,timer-pwm", NULL) ||
> 197 of_get_property(np, "ti,timer-secure", NULL)))
> 198 continue;
> 199
> 200 if (!of_device_is_compatible(np, "ti,omap-counter32k")) {
> 201 struct property *prop;
> 202
> 203 prop = kzalloc(sizeof(*prop), GFP_KERNEL);
> 204 if (!prop)
> > 205 return -ENOMEM;
Correct "return -ENOMEM" to "return NULL;" in case that it fails to
allocate a new memory block.
--
Qi Hou
> 206 prop->name = "status";
> 207 prop->length = sizeof("disabled");
> 208 prop->value = "disabled";
> 209 of_add_property(np, prop);
> 210 }
> 211 return np;
> 212 }
> 213
> 214 return NULL;
> 215 }
> 216
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
--
Best regards,
Qi Hou
Phone number: +86-10-8477-8608
Address: Floor 15, Building B, Wangjing Plaza, No.9 Zhong-Huan Nanlu, Chaoyang District