[ 116/135] kobject: fix oops with "input0: bad kobj_uevent_env content in show_uevent()"
3.2-stable review patch. If anyone has any objections, please let me know.
--
From: Bjørn Mork
commit 60e233a56609fd963c59e99bd75c663d63fa91b6 upstream.
Fengguang Wu writes:
> After the __devinit* removal series, I can still get kernel panic in
> show_uevent(). So there are more sources of bug..
>
> Debug patch:
>
> @@ -343,8 +343,11 @@ static ssize_t show_uevent(struct device
> goto out;
>
> /* copy keys to file */
> - for (i = 0; i < env->envp_idx; i++)
> + dev_err(dev, "uevent %d env[%d]: %s/.../%s\n", env->buflen,
> env->envp_idx, top_kobj->name, dev->kobj.name);
> + for (i = 0; i < env->envp_idx; i++) {
> + printk(KERN_ERR "uevent %d env[%d]: %s\n", (int)count, i,
> env->envp[i]);
> count += sprintf([count], "%s\n", env->envp[i]);
> + }
>
> Oops message, the env[] is again not properly initilized:
>
> [ 44.068623] input input0: uevent 61 env[805306368]: input0/.../input0
> [ 44.069552] uevent 0 env[0]: (null)
This is a completely different CONFIG_HOTPLUG problem, only
demonstrating another reason why CONFIG_HOTPLUG should go away. I had a
hard time trying to disable it anyway ;-)
The problem this time is lots of code assuming that a call to
add_uevent_var() will guarantee that env->buflen > 0. This is not true
if CONFIG_HOTPLUG is unset. So things like this end up overwriting
env->envp_idx because the array index is -1:
if (add_uevent_var(env, "MODALIAS="))
return -ENOMEM;
len = input_print_modalias(>buf[env->buflen - 1],
sizeof(env->buf) - env->buflen,
dev, 0);
Don't know what the best action is, given that there seem to be a *lot*
of this around the kernel. This patch "fixes" the problem for me, but I
don't know if it can be considered an appropriate fix.
[ It is the correct fix for now, for 3.7 forcing CONFIG_HOTPLUG to
always be on is the longterm fix, but it's too late for 3.6 and older
kernels to resolve this that way - gregkh ]
Reported-by: Fengguang Wu
Signed-off-by: Bjørn Mork
Tested-by: Fengguang Wu
Signed-off-by: Greg Kroah-Hartman
Signed-off-by: Ben Hutchings
---
include/linux/kobject.h |2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index fc615a9..1e57449 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -224,7 +224,7 @@ static inline int kobject_uevent_env(struct kobject *kobj,
static inline __printf(2, 3)
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
-{ return 0; }
+{ return -ENOMEM; }
static inline int kobject_action_type(const char *buf, size_t count,
enum kobject_action *type)
--
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[ 116/135] kobject: fix oops with input0: bad kobj_uevent_env content in show_uevent()
3.2-stable review patch. If anyone has any objections, please let me know.
--
From: Bjørn Mork bj...@mork.no
commit 60e233a56609fd963c59e99bd75c663d63fa91b6 upstream.
Fengguang Wu fengguang...@intel.com writes:
After the __devinit* removal series, I can still get kernel panic in
show_uevent(). So there are more sources of bug..
Debug patch:
@@ -343,8 +343,11 @@ static ssize_t show_uevent(struct device
goto out;
/* copy keys to file */
- for (i = 0; i env-envp_idx; i++)
+ dev_err(dev, uevent %d env[%d]: %s/.../%s\n, env-buflen,
env-envp_idx, top_kobj-name, dev-kobj.name);
+ for (i = 0; i env-envp_idx; i++) {
+ printk(KERN_ERR uevent %d env[%d]: %s\n, (int)count, i,
env-envp[i]);
count += sprintf(buf[count], %s\n, env-envp[i]);
+ }
Oops message, the env[] is again not properly initilized:
[ 44.068623] input input0: uevent 61 env[805306368]: input0/.../input0
[ 44.069552] uevent 0 env[0]: (null)
This is a completely different CONFIG_HOTPLUG problem, only
demonstrating another reason why CONFIG_HOTPLUG should go away. I had a
hard time trying to disable it anyway ;-)
The problem this time is lots of code assuming that a call to
add_uevent_var() will guarantee that env-buflen 0. This is not true
if CONFIG_HOTPLUG is unset. So things like this end up overwriting
env-envp_idx because the array index is -1:
if (add_uevent_var(env, MODALIAS=))
return -ENOMEM;
len = input_print_modalias(env-buf[env-buflen - 1],
sizeof(env-buf) - env-buflen,
dev, 0);
Don't know what the best action is, given that there seem to be a *lot*
of this around the kernel. This patch fixes the problem for me, but I
don't know if it can be considered an appropriate fix.
[ It is the correct fix for now, for 3.7 forcing CONFIG_HOTPLUG to
always be on is the longterm fix, but it's too late for 3.6 and older
kernels to resolve this that way - gregkh ]
Reported-by: Fengguang Wu fengguang...@intel.com
Signed-off-by: Bjørn Mork bj...@mork.no
Tested-by: Fengguang Wu fengguang...@intel.com
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
Signed-off-by: Ben Hutchings b...@decadent.org.uk
---
include/linux/kobject.h |2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/kobject.h b/include/linux/kobject.h
index fc615a9..1e57449 100644
--- a/include/linux/kobject.h
+++ b/include/linux/kobject.h
@@ -224,7 +224,7 @@ static inline int kobject_uevent_env(struct kobject *kobj,
static inline __printf(2, 3)
int add_uevent_var(struct kobj_uevent_env *env, const char *format, ...)
-{ return 0; }
+{ return -ENOMEM; }
static inline int kobject_action_type(const char *buf, size_t count,
enum kobject_action *type)
--
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