* [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device
@ 2020-11-03 6:52 Wang Wensheng
2020-11-03 6:52 ` [PATCH -next v2 2/2] watchdog: Fix potential dereferencing of null pointer Wang Wensheng
2020-11-03 7:05 ` [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Christophe Leroy
0 siblings, 2 replies; 4+ messages in thread
From: Wang Wensheng @ 2020-11-03 6:52 UTC (permalink / raw)
To: wim, linux, linux-watchdog, linux-kernel; +Cc: rui.xiang, guohanjun
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
---
drivers/watchdog/watchdog_core.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index 423844757812..c73871f41142 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -252,10 +252,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
wdd->id = id;
ret = watchdog_dev_register(wdd);
- if (ret) {
- ida_simple_remove(&watchdog_ida, id);
- return ret;
- }
+ if (ret)
+ goto id_remove;
}
/* Module parameter to force watchdog policy on reboot. */
@@ -273,9 +271,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
if (ret) {
pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
wdd->id, ret);
- watchdog_dev_unregister(wdd);
- ida_simple_remove(&watchdog_ida, id);
- return ret;
+ goto dev_unregister;
}
}
@@ -289,6 +285,13 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
}
return 0;
+
+dev_unregister:
+ watchdog_dev_unregister(wdd);
+id_remove:
+ ida_simple_remove(&watchdog_ida, id);
+
+ return ret;
}
/**
--
2.25.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH -next v2 2/2] watchdog: Fix potential dereferencing of null pointer
2020-11-03 6:52 [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Wang Wensheng
@ 2020-11-03 6:52 ` Wang Wensheng
2020-11-03 7:05 ` [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Christophe Leroy
1 sibling, 0 replies; 4+ messages in thread
From: Wang Wensheng @ 2020-11-03 6:52 UTC (permalink / raw)
To: wim, linux, linux-watchdog, linux-kernel; +Cc: rui.xiang, guohanjun
A reboot notifier, which stops the WDT by calling the stop hook without
any check, would be registered when we set WDOG_STOP_ON_REBOOT flag.
Howerer we allow the WDT driver to omit the stop hook since commit
"d0684c8a93549" ("watchdog: Make stop function optional") and provide
a module parameter for user that controls the WDOG_STOP_ON_REBOOT flag
in commit 9232c80659e94 ("watchdog: Add stop_on_reboot parameter to
control reboot policy"). Together that commits make user potential to
insert a watchdog driver that don't provide a stop hook but with the
stop_on_reboot parameter set, then dereferencing of null pointer occurs
on system reboot.
Check the stop hook before registering the reboot notifier to fix the
issue.
Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
---
drivers/watchdog/watchdog_core.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
index c73871f41142..5269761ba072 100644
--- a/drivers/watchdog/watchdog_core.c
+++ b/drivers/watchdog/watchdog_core.c
@@ -265,8 +265,12 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
}
if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) {
- wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
+ if (!wdd->ops->stop) {
+ ret = -EINVAL;
+ goto dev_unregister;
+ }
+ wdd->reboot_nb.notifier_call = watchdog_reboot_notifier;
ret = register_reboot_notifier(&wdd->reboot_nb);
if (ret) {
pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
--
2.25.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device
2020-11-03 6:52 [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Wang Wensheng
2020-11-03 6:52 ` [PATCH -next v2 2/2] watchdog: Fix potential dereferencing of null pointer Wang Wensheng
@ 2020-11-03 7:05 ` Christophe Leroy
2020-11-03 13:05 ` Guenter Roeck
1 sibling, 1 reply; 4+ messages in thread
From: Christophe Leroy @ 2020-11-03 7:05 UTC (permalink / raw)
To: Wang Wensheng, wim, linux, linux-watchdog, linux-kernel
Cc: rui.xiang, guohanjun
Hi,
Can you provide in the commit a description of what you are doing and why ?
Christophe
Le 03/11/2020 à 07:52, Wang Wensheng a écrit :
> Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
> ---
> drivers/watchdog/watchdog_core.c | 17 ++++++++++-------
> 1 file changed, 10 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
> index 423844757812..c73871f41142 100644
> --- a/drivers/watchdog/watchdog_core.c
> +++ b/drivers/watchdog/watchdog_core.c
> @@ -252,10 +252,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
> wdd->id = id;
>
> ret = watchdog_dev_register(wdd);
> - if (ret) {
> - ida_simple_remove(&watchdog_ida, id);
> - return ret;
> - }
> + if (ret)
> + goto id_remove;
> }
>
> /* Module parameter to force watchdog policy on reboot. */
> @@ -273,9 +271,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
> if (ret) {
> pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
> wdd->id, ret);
> - watchdog_dev_unregister(wdd);
> - ida_simple_remove(&watchdog_ida, id);
> - return ret;
> + goto dev_unregister;
> }
> }
>
> @@ -289,6 +285,13 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
> }
>
> return 0;
> +
> +dev_unregister:
> + watchdog_dev_unregister(wdd);
> +id_remove:
> + ida_simple_remove(&watchdog_ida, id);
> +
> + return ret;
> }
>
> /**
>
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device
2020-11-03 7:05 ` [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Christophe Leroy
@ 2020-11-03 13:05 ` Guenter Roeck
0 siblings, 0 replies; 4+ messages in thread
From: Guenter Roeck @ 2020-11-03 13:05 UTC (permalink / raw)
To: Christophe Leroy, Wang Wensheng, wim, linux-watchdog, linux-kernel
Cc: rui.xiang, guohanjun
On 11/2/20 11:05 PM, Christophe Leroy wrote:
> Hi,
>
> Can you provide in the commit a description of what you are doing and why ?
>
Also, I'd rather have this as second patch to make it easier (possible, actually)
to apply the first patch to -stable.
Guenter
> Christophe
>
> Le 03/11/2020 à 07:52, Wang Wensheng a écrit :
>> Signed-off-by: Wang Wensheng <wangwensheng4@huawei.com>
>> ---
>> drivers/watchdog/watchdog_core.c | 17 ++++++++++-------
>> 1 file changed, 10 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/watchdog/watchdog_core.c b/drivers/watchdog/watchdog_core.c
>> index 423844757812..c73871f41142 100644
>> --- a/drivers/watchdog/watchdog_core.c
>> +++ b/drivers/watchdog/watchdog_core.c
>> @@ -252,10 +252,8 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
>> wdd->id = id;
>> ret = watchdog_dev_register(wdd);
>> - if (ret) {
>> - ida_simple_remove(&watchdog_ida, id);
>> - return ret;
>> - }
>> + if (ret)
>> + goto id_remove;
>> }
>> /* Module parameter to force watchdog policy on reboot. */
>> @@ -273,9 +271,7 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
>> if (ret) {
>> pr_err("watchdog%d: Cannot register reboot notifier (%d)\n",
>> wdd->id, ret);
>> - watchdog_dev_unregister(wdd);
>> - ida_simple_remove(&watchdog_ida, id);
>> - return ret;
>> + goto dev_unregister;
>> }
>> }
>> @@ -289,6 +285,13 @@ static int __watchdog_register_device(struct watchdog_device *wdd)
>> }
>> return 0;
>> +
>> +dev_unregister:
>> + watchdog_dev_unregister(wdd);
>> +id_remove:
>> + ida_simple_remove(&watchdog_ida, id);
>> +
>> + return ret;
>> }
>> /**
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-11-03 6:52 [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Wang Wensheng
2020-11-03 6:52 ` [PATCH -next v2 2/2] watchdog: Fix potential dereferencing of null pointer Wang Wensheng
2020-11-03 7:05 ` [PATCH -next v2 1/2] watchdog: Clean up error handlings of __watchdog_register_device Christophe Leroy
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